This document provides information on plantation forestry globally and in Nepal. Key points include: - Plantation forestry has expanded globally over the past century and a half, with new plantations established at a rate of 4.5 million hectares per year. - Asia accounts for over 60% of the world's planted forests, with plantations concentrated in countries like China, India, and Malaysia. - Plantation forestry in Nepal began in the 1950s and has increased forest cover in the country by 14% between 1937-1947. - Challenges to expanding natural forests like degradation and lack of regeneration have driven the growth of plantation forestry worldwide.

1. Silviculture Note
Unit: 1 Plantation forestry
Forest stands established by planting/seeding in the process of afforestation or reforestation
either of introduced (exotic) or indigenous species with minimum area of 0.5 ha, tree crown
cover of at least 10% of land cover, and total height of adult trees above 5 m (FAO)
 Rubber plantation (for fibre) , previously under agri. Plantation, is now under forest
plantation
 New forest plantation are established globally at the rate of 4.5 million ha/yr
 Industrial plantation-48%
 Non-industrial plantation-26%
 Plantation for unspecified use-26%
 Total planted forest: Africa A/P LAC Total
 (Million ha) 0.95 12.0 9.4 22.4 (2010)
 0.82 38.3 5.6 44.8 (2005)
 Source: country profiles in ITTO (2011)
 Distribution of forest plantation
 Asia-62% Europe-17%, N. and C. America-9%
 S. America-6% Africa-4% Oceania-2%
 (source: Global Forest Resource Assessment, FAO, 2001)
 Deforestation (mainly conversion to agri.)-13 million ha/yr
 Increase for industrial plantation and decrease for non-industrial plantation
 Increasing potential for plantation investment to offset carbon emissions
 Tropical and subtropical forest plantation constitute 44.7% of global resource
 Annual rate of forest plantation establishment in tropical and subtropical countries are
more than 4 million ha/yr
Why plantation?
1. Past and continuing destruction of natural forest.
In the past 150-200 years, forest destruction has taken place in every country. Forest
disappears at a rate of 15-20 million ha/year in developing countries.
Between 1990 and 2010, more than 30% of tropical forest was cleared in Asia and 15-
20% in rest of the world.
2. Problem of access to existing forests; physical limitation, high slope, mountains, swampy
ground, no infrastructure of road, communication and service.
3. Unsatisfactory natural regeneration due to biotic influence.
4. High productivity of plantation than existing forest.
5. High demand of industrial materials.
 Teak-10.5 cum/ha/yr, E.cameldulensis-30 cum/ha/yr
 Pinus caribaea-40 cum/ha/yr, Sissoo-18.1 cum/ha/yr
 Pinus roxburghii-15 cum/ha/yr, tropical high forest (managed)-0.5-7 cum/ha/yr
 Tropical hardwood plantation-25-35 cum/ha/yr
 5. Environmental protection
 Plantations cover more than 100 million ha worldwide
 Plantation for reclamation of degraded forest lands, protection of watersheds,
plantation for environmental purposes
 Malaysia has 250,000 ha of forest plantations (2005)
 China, Russian Federation, USA, India and Japan each have established more than 10
million ha of forest plantations
Plantation forestry in Nepal
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2. Silviculture Note
 Plantation programme started from 1st
five year plan (2013-17)
 1st
five year plan (2013-17) 153 Acre
 2nd
five year plan (2017-21) 2,454 ha
 3rd
five year plan (2022-27) 41,50 ha
 From 2023, afforestation program was launched as a separate project up to 2028. The
plantation was confined to Kathmandu valley.
 From 2029 onwards, the program was launched in Terai and middle mountains
 4th
five year plan (2027-32) 2,454 ha
 5th
five year plan (2032-37) 9,596 ha
 6th
five year plan (2037-42) 12,096 ha (community forest development project)
 7th
five year plan (2042-47) 11,255 ha
 During period from 2037-047, area under forest plantation has increased by 14% in
Nepal (World Resource Institute, 1998)
Major plantation programmes
 Sagarnath forest development project/ program (2035/36) 11,000 ha
 Ratuwamai plantation project (2040/41) 2,900 ha
 Nepalgunj forest development project, Kohalpur (2043) 5,000 ha
 Chautara forest development project 2035/36
 Integrated rural development project in 6th
five year plan
 Hill forest development project 2040-41.
 Private forests, farm forestry – 1985 by Butwal plywood.
 Leasehold forestry 2049 Act.
 TCN plantation in terai, species was sisoo only.
 Plantation trials of Research Division in different ecological zones. Comprises
mainly of tropical pines.
 Provenance trial of sisoo at Adavar.
 Pakribas Agriculture Research Centre- sisoo, gurans, ficus, utis, khote sallo,
gobre sallo, okhar, katus, bakaeno, sal, etc. on trial planting.
 Research is on fodder species on CF.
 Tamagarhi Taungya Plantation 1976-89, more than 50 families.
 CF plantation of more than 5000 ha supported by Nepal Australia Forestry
Project and CF development project in hills.
 Terai CF project launched in 1984, covered 13 districts, targeted 26,000 ha,
achieved 19,260 ha including 13,500 ha private plantation.
 Departmental plantation of 2,250 ha. Road, canal, 2,900 ha agro-forestry.
Plantation in the Tropics
Plantation before 1900
 People have been planting trees for thousands of years for food, shelter, ceremonial or
religious purposes. Bible records Abraham planting a tree Tamarisk tree which is
historical record exists.
 It is actually in the tropics, in the Srilanka where the Bodhi tree (Ficus religiosa) is
recorded about 220 BC.
 The present development of manmade forestry can be traced back to the sixteenth and
seventeenth centuries when exploration and expansion of European influence took
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3. Silviculture Note
place. They collected numerous species from the world to scientific study among them
many species failed.
 But as early as 1680, Teak was introduced in Srilanka which became success. In 1829,
Teak success in Java, Indonesia. In 1940, teak was planted in India in Nilamber hills,
in Bangladesh, in 1871.
 In 1843, Eucalyptus globules in Nilgiri India, Eucalyptus and watalus in Madras in
1832. And as early as 1790 several Eucalyptus were planted in the garden at Nandi
hills near Mysore.
 In 1823, eucalyptus was planted in South America in Chile.
 In 1825 E. globules and E. territicornis in Africa.
 Before 1900, Pinus patula was introduced in New-zealand in 1877.
 In 1830 Myanmar introduced teak to arrest shifting cultivation by converting to
Taungya. Between 1856- 68, 320 ha of teak planted and by 1900 about 8,000 ha
 In 1866, Changamanga plantation of sisoo in Pakistan.
Plantation during 1900-1945
 By 1945, in South Africa 180,000 ha plantation of tropical pines and eucalyptus
species was done.
 In Australia (Queensland) 9,800 ha of Araucaria and pines planted.
 In India, by 2nd
world war, 80,000 ha of teak was planted and many more trials of
eucalyptus.
 In Brazil, between 1920 and 1930, several hundred thousand hectares of eucalyptus
were planted.
 In South Africa, in 1920, about 115,000 ha of wattle (Acacia mearnsii) in the form of
industrial plantation for tan bark was carried out.
 By 1931, 25,500 ha in Kenya.
Plantation during 1945- 1965
 In China, 100,000-450,000 ha/ year – china fir (cunninghamiana lanceolata) was
planted in south, most tropical provinces.
 By 1958 in Africa largest block plantation 41,000 ha. The Usutu forest in Swaziland.
Infact between 1945-65 more than 80,000 ha or 5% of the total land surface.
 Late 1950 Fiji planted Swertenia mycrophylla
 In Papua New Guinea in 1951 planted Araucaria
 In 1965, the approximate area of plantation in the tropics was 3.5-4.0 million ha (FAO,
1967) including those of Southern China.
Plantation during 1966-1980
 Between 1966 and 1977, the rate of planting in Brazil rose from 40,000 ha/ yr. By
1980, 100,000 ha were planted and pulp mill operated.
 Between 1971-79, a small country Fiji planted 28,000 ha of Pinus caribea.
 Between 1966 and 1980, 15,000 ha of Eucalyptus planted in Congo and in Sudan
180,000 ha was planted.
 In India, between 1966 and 1979, 2.8 million ha pf new plantation was establish.
 In the five southern tropical provinces of China, Eucalyptus plantation expanded
rapidly by 6 million ha in 1980.
 In 1980, according to FAO (1988) of 11.5 million ha plantation in tropical countries,
among them 7.2 million ha for industries and 4.3 million ha for non-industrial purpose.
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4. Silviculture Note
 World forestry congress held in 1972 “The Forest and Economic Development”; in
1978, “Forest for People”, FAO 1978 “ Forestry for Rural Communities”, “Trees,
Food and People”, “Land Management in the Tropics” “Forest Energy and Economic
Development” etc.
 In the 1970, many organizations involved to encourage tree planting in tropics such as
World Bank, ITTO, many NGOs, INGOs, ICRAF, FAO, USAID, Winrock, Danida,
Finida, Swiss etc have been supporting for planting trees in tropics.
 Besides these, many donor countries have been supporting for tree improvement and in
social/ community/ collaborative/ participatory/ joint management forestry sectors.
Program of planting up to 2000
 In Burundi, 300,000 ha
 Malaysia, 500,000 ha
 Ethiopia, 3.5 million ha
 Indonesia, 300,000 ha
 India, 17 million ha
 Brazil. 12 million ha
 China increases coverage by 12-20%
 Nepal increase 42% coverage
Plantation characteristics
 Plantations are usually near or totally monoculture whereas natural forest would
contain a far more diverge range of tree species
 Plantations may include tree species that would not naturally occur in the area. Pine,
spruce and eucalyptus are widely planted beyond their natural range due to their fast
growth rate, tolerance of rich or degraded agricultural land and potential to produce
large vol. of raw materials for industrial use
 Plantations are always young forests in ecological terms (10 to 60 years rotations)
 Disturbances related to site preparation can open way for invasion by aggressive
undesirable vegetation Stocking of stands is fuller and more uniform than is possible
with any other mode of regeneration
 Trees planted can represent best genetic material available and be carefully fitted to the
site
 Growth of planted trees can often be improved by fertilization or by reducing any
competing vegetation
 With planting, it is possible to govern the density, spacing pattern, species
composition, and genetic constitution of new stand more precisely
 More dependable kind of regeneration
Artificial Regeneration in Difficult sites
Renewal of a forest crop by sowing, planting or other artificial means. Normally such a crop is
called-Plantation.
• Sowing of seeds directly on an area
• Planting or transferring of seedlings or plants in the area to be regenerated.
• Wilding ( natural seedlings used in planting).
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5. Silviculture Note
Plantation
i. Reforestation: plantation on a site having forest vegetation before.
ii. Afforestation: plantation on a site where forest vegetation has long or always
been absent.
Objectives of Reforestation:
i. To supplement natural regeneration
ii. To give up natural reg. in favor of artificial regeneration.
iii. To restock forests destroyed by fire or other biotic factors.
iv. To change the composition of crops
v. To introduce exotics.
Objectives of Afforestation:
i. To increase the production of timber.
ii. To increase the production of fuel and small timber.
iii. Improvement of Agroecosystem
iv. Moderation of climate.
v. Soil conservation.
vi. Protection of catchment of rivers.
vii. Increasing natural beauty of landscape.
Afforestation of denuded hills:
Locality factors:
 Soil is usually shallow and stony.
 Infertile soil
 Some places have bare rocks.
 Exposure to sun and drying winds.
 Excessive run-off deficiency of soil moisture.
 Incidence of grazing and illegal felling.
Soil Preparation:
Trenches:
 Contour trenches are usually made on slopes up to 20%
 The trenches may be continuous or interrupted
 The interrupted trenches are better
 The trenches are usually 3m long and 30cm deep.
 Trenches may be 2-4.5m apart depending upon the angle of slope.
Pits or Patches:
 In rocky areas where trenches cannot be made, patches for sowing or pits for planting
may be made without bothering the regular spacing.
Method of Raising:
• Sowing and planting are both suitable
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6. Silviculture Note
Choice of Species:
Indigenous, pioneer, non palatable sp. i.e. Alnus, Pinus in subtropical areas
Blue pine, Deodar in Temperate areas.
Acacia, Eucalyptus (dry subtropical).
Tending and protection
• Weeding and clearing frequently required.
Protection from grazing and browsing animals
Afforestation of grasslands:
Factors of Locality:
• Soil aeration and drainage is poor.
• Some grasses form den to roots of roof.
• Some grasses develop extensive root system.
• There is danger of fire and forest.
• Regeneration may be destroyed by wild animals.
Soil Preparation:
• Patches are not suitable except in hills
• Soil preparation in strips
• Area should be ploughed if possible
• Taungya method may be suitable.
Choice of species:
• Fast growing, frost and fire hardy
• Sissoo, Khair, Simal, Siris, Eucalyptus.
• Treminalia
• Trewia nudiflora in wet places.
• Chirpine and blue pine in W. Himalayas
• Populas cilliata in moist nalas.
Method of Raising:
• Sowing and planting are both suitable
• Taungya method
Tending and protection
• Weeding and cleaning frequently required.
• Protection from grazing and browsing animals.
• Protection against fire is necessary by making fire lines.
Afforestation of Abandoned cultivated lands
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7. Silviculture Note
Factors of locality:
• Soil fertility is generally low due to washing away of the top soil.
• The drainage, infiltration capacity and aeration of such soils are also poor.
• There is generally heavy infestation of weeds
• Full exposure to sunlight and damage by grazing and browsing.
Soil preparations:
• Soil may be dug in strips.
• If its area is large plain, tractor plough may be done.
• Improve drainage, old bunds be demolished
• Afforestation by taungya method.
Choice of Species:
• Depends on ease in raising, rate of growth, and frost hardiness.
• Species in the earlier stages of natural succession should be selected.
• Dalbergia, Eucalyptus, Terminalia tomentosa.
• Chir and blue pine in the Himalayas.
Method of raising:
• Sowing and planting are both suitable.
• Polythene bag plants or stumps may be used.
• Sowing should be done in strips.
• Mix plantation should be done
Tending and Protection
• Weeding and cleanings have to be done for several years.
• Protection from grazing and browsing animals.
• Protection against fire is necessary.
Afforestation of Ravine land
The ravines have not only rendered extensive areas barren but are also posing threats to the
cultivated lands above by their continuous extension backward and destroying the vegetative
corer.
Factors of Locality:
• Soil is generally sandy to stiff clay.
• Less moisture in the top of the soil.
• Formation of hillocks and ridges in between ravines
• The hillocks and ridges have practically no contact with permanent water table.
• Ravines experience forest.
• Uncontrolled falling, grazing and fire are present.
Soil Preparation:
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8. Silviculture Note
1) Soil Preparation in the catchments:
a) Cultivated lands:
• Contour bunds are made at suitable intervals
• For safe disposal of excess water some nalas are also made through grassed
water ways.
b) Waste lands near ravines:
• Interrupted contour trenches of 1.5m or 3m long 60cm wide and 45cm deep and 3.5-
4.5m apart are made.
• In every fifth line a continuous trench is made.
• Two continuous trenches are made at an interval of 4.5m all around the three sides of
the ravine with the first continuous trench at about 2.5m apart from the bank of ravine.
2. Soil preparation on the slopes of head and sides of ravines:
• A continuous trench is made at about 2.5m from the base and sides of ravines.
• Then interrupted contour trenches are made at an interval of 4.5m and continuous
trenches are made in every 5th
line.
3. Soil preparations in the valleys:
• In the valleys which are 2.5m-10m wide continuous trenches are made.
The first trench is made 2.5m away from the base of the head of ravine and there after they are
made at an interval of 4.5m.
In valleys more than 10m wider, interrupted trenches are made but every 5th
line is a
continuous trench.
Choice of Species:
1. Clayey soil:
Acacia Arabica
Ailanthus, Albizzia, Syzygium
Terminalia arjuna
Dalbergia sisso is best in valleys instead of acacia Arabica due to frost problem.
2. Sandy soils:
Acacia catechu
Dalbergia sisso
Albizzia, Melia azedarach
Prosopis juliflora
Azederachta indica (Nim)
Method of Raising Plants:
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9. Silviculture Note
Sowing is one or two lines on the ridge but species which are best raised by planting are raised
by entire planting or stump planting.
Tending and Protection:
• Weeding and cleaning are done.
• The area is protected from grazing.
Afforestation of dry areas without irrigation
• Dry area may be defined as an area which receives less than 900mm of rainfall
annually.
• Annual rainfall varies from 250-750mm in dry areas of India.
Factors of locality:
• Soil varies from place to place and deteriorated considerably.
• Less moisture and high temperature.
• Severe forest in winter.
• Human and animal pressure is great.
Soil preparation:
• Deep pits are made
• In sloppy areas interrupted trencher are made
Choice of Species:
Acacia arabica, Acacia cateachu, Dalbargia sisso.
Albizzia lebeck, Ailanthus, excelsa,
Ziziphus, Cassia fistula, Cassia simea, Azedirachta indica. Eucalyptus.
Prosophis juliflora
Method of Raising:
Most of the species can be raised by direct sowing but as the moisture in a constraint
polythene bag seedlings are planted.
Tending and Protection:
• Weeding and cleaning are done.
• The area is protected from grazing.
Afforestation of dry areas with irrigation
If irrigation is available dry areas can be afforested with irrigation.
• Factors of locality:
• Less rainfall
• Less soil moisture and high temperature
• Winter Forest
• Low water table
9

10. Silviculture Note
Soil preparation:
• Area should be thoroughly leveled
• Plough and harrowing the field
• The area can be divided in to rectangular compartments and should be connected with
irrigation channels.
Choice of species:
Dalbergia sissoo
Eucalyptus, Bombax ceiba, Morus, Syzygium, Acacia arabia.
Method of raising:
Sowing, planting by polythene bag grown seedlings or stump planting plantations are irrigated
for 2-3 years at least.
10-15 irrigation in first year.
6-10 irrigation in 2nd
year.
5 irrigation in 3rd
year.
Tending and Protection:
Weeding and cleaning are done.
The area is protected from grazing.
Weeding is necessary up to two years.
Afforestation of canal banks:
Factors of locality:
• Soil ranges from sandy to clayey.
• Soil moisture condition is good.
• At places there may be water logging.
• The climate varies from place to place.
• The pressure of human and animal is excessive.
Soil preparation:
• Pits of 60cm × 60cm × 60cm are dug for planting on left side of canal.
• In the water logged places mounds 60cm × 60cm at the top and 1.8m × 1.8m at the
base and with height usually 1.2m or more depending on depth of water logged are
made.
• On the right bank, interrupted trenches 60cm wide, 30cm deep with length 1.5m-
3m are made.
• The first row of plants along the outer edge of canal road is made 6m apart.
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11. Silviculture Note
• The other rows are 3m apart and the pits are also 2-3m apart.
Choice of species:
Dalbergia sissoo, Acacia catechu, Albizzia, Ailanthus, Melia, Eucalyptus, Acacia arabica.
Methods of raising:
• The species are generally planted with a ball of earth or as container plants.
• Sissoo is raised by sowing or planting.
• Khair, Babul, Siris and Ailanthus by sowing.
Tending and Protection:
• Weeding and cleaning are done.
• The area is protected from grazing.
Afforestation of roadside strips
Factors of locality:
• The climate varies from place to place.
• The soil varies from sandy to stiff clay.
• The borrow pits upset the natural drainage and became water logged.
Soil preparation:
• Pits 60cm in diameter and 6cm deep for mango and sissoo.
• Pits 45cm in diameter and 45cm in deep for Eucalyptus and other species.
• Multiple rows i.e. 3 rows on either side.
• Pits may be 12m apart for bigger crown tree.
• Pits may be 6m apart for sissoo
• Pits may me 3m for Eucalyptus.
Choice of Species:
• Species should be handy, evergreen or winter deciduous wind firm, and fast growing
and fairly tall.
• Good crown but not drooping branches.
• Species with edible fruits and valuable timber are prepared.
• The choice of species is governed by climate (temp, rainfall), soil and water table.
Acacia arabica, Azadirachta indica, Albizzia procera, Dalbergia sissoo, Eucalyptus, Fiscus
species, Madhuca, Mangifera, syzygium, Terminalia arjuna (water logged).
In saline alkaline soils- Prosopis juliflora and Parkinsonia aculata.
Ornamental plants have also been planted.
Callistemon viminalis, Cassia-fistula, Bauhimia variagata, Delonix regia, Jacaranda ovulifolia,
Grevillea robusta.
In the hills- Populas nigra, Populas alba, Acer oblongum, Ailanthus altissima.
Methods of Raising:
• Nursery grown tall plants with ball of earth or raised in containers.
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12. Silviculture Note
• The minimum height suitable is 2.4m for sissoo (3 years 1.5m for other sp.).
• Ficus- 8-10cm in India and about 2.5m long stakes are planted about 60 cm is buried in
soil.
• Farm yard manure is mixed in the soil watering is necessary in the first and 2nd
dry
seasons.
• Beating up is done in the same or in the second year
Protection:
• Construction of mud wall.
• Construction of open brick work.
• Live circular hedge of Acacia Arabica, Opuntia, Agave, Euphorbia
• Old coal tar drums
• Circular trench
• Stacks are used to give support.
Afforestation of Shifting Sands
Shifting sands are found along sea or wells as in the interiov. The inland sands are found
along large rivers and in deserts.
• Coastal sand
• Inland river sand
• Desert areas
1. Afforestation of coastal lands
All along the sea coast, large quantities of sand get accumulated a a result of tides.
Factors of Locality:
• The soil is pure sand
• The soil is unstable and un-retentive of moisture.
• The depth of water table is generally fairly high.
• The water is generally slightly brackish.
• Rainfall is usually ample
• Atmospheric humidity is high
• The winds are strong and carry salt and sand.
• The human and cattle population pressure is great and poses a real threat to the
plantation.
Soil preparation:
As the soil is loose sand, only pits are dug. They are generally 30cm in diameter and 30cm
deep with varying spacing from 1.8m × 1.8m to 3.6m × 3.6m in different localities.
Sometimes along the high tide mark areas spacing is reduced to 1m × 1m with object of
creating a shelter belt.
Choice of species:
Casuarinas equisetifolia is the best.
Eucalyptus hybrid, Pongamia pinnata, Acacia auriculiform, Prosopis juliflora
(in dry areas of Gujrat).
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13. Silviculture Note
In Casuarina Casualties are often beaten up with Anacardium occidentalis which creates a two
tier effective wind barrier and fetches a handsome revenue (in Orissa).
Method of Raising:
Casuarina is usually planted with naked root (bare root seedlings) but is also planted with ball
of earth (container plants).
Planting is usually done in June-July. Plants are watered during the first year but in places pf
deep water table watering is done in the second and even third year.
When plantation is raised very near to shore or in areas subjected to strong wind some
protective screens become necessary.
Protection:
Plantations are protected against cattle by erecting cattle proof fence.
2. Afforestation of Inland River Sand
Factors of Locality:
• Sandy waste lands are found along big rivers.
• The soil is sandy, unstable and deficient in nutrient.
• Water table is not deep and so well irrigation is possible.
• Rainfall and atmosphere humidity is low.
• Day temperature is high
• Diurnal range of temperature is fairly wide.
• Severe forest occurs during winter.
• Pressure of animal and human population is excessive.
• Indiscriminate lopping for fuel and fodder.
Soil Preparation:
Soil preparation consists digging trenches and pits.
Choice of species:
Dalbergia sissoo, Acacia catechu, Acacia arabica, Albizzia procera.
Azadirachta indica, Melia azederach, Ailanthus excelsa, have also been tried successfully.
Methods of raising plants:
As soil is shifting loose sand, it has first to be stabilized by planting grasses. Eulalipsis binata
(babai grass) and Saccharum are commonly used. Planting is preferred to sowing so that the
roots of plants should reach deep as nearly as possible.
3. Afforestation of Desert Areas
Factors of Locality:
1. There is great extreme of temperature 3-48 degree centigrade.
2. Strong hot winds with velocities over 100km/hr.
3. The diurnal variation of temperature is also sudden.
4. Severe forest during winter
5. Rainfall is very low and varies from 100mm to about 800mm.
6. Relative humidity is low and evaporation is generally more.
7. Soil varies from place to place. On the whole it is sand to sandy.
8. Soil is alkaline or saline with unfavorable physical condition and ph.
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14. Silviculture Note
9. In places there are thick beds of Kankar or gypsum below the sand.
10. The water table is generally very low up to 100m or more.
11. Soil is susceptible to wind erosion.
12. The pressure of animal and human population is excessive.
13. Raring of cattle, sheep, goats, horses, and camels is the main occupation of
people.
14. The few scattered trees are heavily lopped for fodder and fuel.
15. Rats, Termites and Locust are serious problems.
Afforestation Techniques:
1. Sand dune stabilization
2. Creation of wind breaks and shelterbelts.
3. Development of fuel and fodder block.
1. Sand dune stabilization:
• Close the area effectively against grazing and burning by erecting a cattle proof
fence of barked wire.
• Mulching is done in April and May
• Just before commencement of rains sowing of the following species is done.
Grasses: Panicum antidotale, Lasiurus hirsutus
Shrubs: Calligonum, Ziziphus, Cassia auriculata.
Trees: Prosopis spicigera, Prosopis juliflora, Acacia arabia, Acacia Senegal
• After the rain is set grasses like Saccharum munja, Panicum antidotale, Panicum
turgidum are planted at about 1m × 1m spacing.
• In addition Acacia arabica, Acacia Senegal Prosopis spicigera, Prosopis juliflora,
Tamarix articulata, Albizzia lebbek, Azadirachta indica, Eucalyptus sp. etc are also
planted.
• Watering is done (about 18 liters per plant for watering is done 5-6 times in Rajasthan)
2. Creation of wind breaks and shelterbelts:
Windbreaks:
• Windbreak is a protection planting round a garden, farm or field to protect it against
strong winds.
• It usually consists of one or two rows of trees, shrubs spaced at 0.5m to 2.5m apart.
• For this purpose 0.5m-1m earthen ridges are made along the field boundaries and
Saccharum munja is planted on it.
• Castor seeds are also sown occasionally.
• In addition Prospis spicigera, Dalbergia sissoo, Tamarind species are also planted on
the ground along the boundary of the farm or orchard.
Shelterbelts:
Shelter belt is a wide belt of trees, shrubs and grasses planted in rows right across the land at
right angles to the direction of Prevailing wind, to develop air current; to reduce wind velocity
and to give general protection to cultivated areas, against wind erosion and desiccating affect
of hot winds.
14

15. Silviculture Note
Choice of species:
• It is better to raise local species.
• But suitable and properly tried exotics can also be used.
• The species selected should be fast growing, wind firm drought restricted and
unpalatable.
• It should have a dense crown and low branching habit.
• The species should be multipurpose, fit to fuelwoood, timber and fodder.
The following species are recommended,
Grasses:
Cenchrus barbatus, Saccharum spontaneum, Saccharum munja, Panicum turgidum, P.
antidotale.
Shrubs:
Calotropis procera, Crotolaria, Clerodendron, Cassia auriculata, Jatropha curcas, Agave sp.,
Sesbania aculeata.
Small trees:
Accacia jacqemontii, Acacia leucophloea, Capparis aphylla, salvadora oleoides
Trees:
Acacia arabica, Acacia Senegal, Albizzia lebbek, Azadirachta indica, Dalbergia sissoo,
Parkinsonia aculeata, Prosopis spicigera, Prosopis juliflora, Tecoma undulata, Tamarix
articulata, Eucalyptus sp.
Methods of raising:
• Seeds are sown in Polythene bags and plant the seedlings.
• The plants should be regularly watered for one or two years.
• Properly fenced for protection.
Advantages of shelter belt:
• Moderating effect on temperature: by lowering the maximum and raising the
minimum.
• Increase in humidity: Increase relative humidity 1-5%.
• Reduction in evapotranspiration.
• Increase in soil moisture.
• Reduction in wind velocity.
• Increase in agricultural and horticultural crops.
• Protection from damage to public and private property.
• Other benefits: fuelwood, fodder, timber
Afforestation of saline and alkaline soils
• PH is usually high
• Often there is kanker pan in the soil
• The pressure of human and animal population is high.
Soil Preparation:
The principal requisites of good soil working in the areas are:
15

16. Silviculture Note
1. Maximum retentivity and utilization of rain water.
2. Maximum reduction of salt concentration in the active root zone of young plants
through leaching.
3. Use of soil amendment (even import of salt free soil) where necessary.
4. Perforation of kankar pan when it exists subsoil.
• Keeping the above points in view, various methods of soil working i.e. pits,
augar holes and trenches of different sizes and shapes are used in different
places.
• The usual method is to dig pits and patches.
• In areas of kankarpan the pits are fairly deep (1.2m) to perforate the pan.
• In patches of good soil, it is filled back.
• Salt affected soil is treated for amendment.
• In worst areas soil is changed with imported salt free soil to provide a favorable
medium for initial growth.
• In saline soil, however trench method has been found to be fairly suitable (in
U.P, Gujrat).
• In Andhra Pradesh trenching and bunding is done and seeds are sown on
bunds.
• In waterlogged areas mounds are made.
• For Permanent amendment of soil gypsum, farmyard manure or molasses
should be used.
Height increment (cm.) of differ. Species on sodic soil (Alkali soil).
Soil
Treatment
Acacia
Arabia
Albizzia
lebbek
Eucalyptus
hybrid
Prospic
juliflora
Terminalia
arjuna
Farmyard
manure 76 46 62 81 68
Gypsum 88 62 91 92 85
Gypsum and
Farmyard
manure
102 71 120 102 95
Normal
(soilreplaced) 107 87 119 100 98
Choice of Species:
Albizzia sp., Terminalia arjuna, Eucalyptus hybrid, Acacia Arabia, Prosopis Juliflora, Acacia
auriculiformis, Leucaena, Leucocephala.
Experiments in U.P. indicated that saline alkali soils with tolerable good drainage and PH up
to 8.5 can be successfully afforested with suitable species in pits with soil amendment
(Gypsum or FYM). But soil with PH varying from 8.5-11 usually associated with poor
drainage and kankarpan can be afforested-Deep pit filled back by non-alkaline soil and
irrigation during summer.
16

17. Silviculture Note
Afforestation of Lateritic Soils
Locality factors:
• Soil is brick red or yellowish brown coloured with hydrated iron oxides and
aluminium oxides.
• Rainfall varies from 750-3750mm.
• Do not experience frost.
• Soil is deficient in nutrients and org. matter content
• Soil is shallow
Soil Preparation:
• Tractor ploughing followed by ridging.
• Trenches or pits may be dug.
• In West Bengal interrupted contour trenches are made 30 × 25cm approximately 3m
apart and the dug up earth is arranged as ridge on the lower side of the trench.
• For Eucalyptus, pits 60cm diameter at the top and 30 cm diameter at the bottom and
50 cm deep are made at a spacing of 2.5m × 2.5m. The pits are filled with pulverized
soil and farm yard manure. The seedlings with ball of earth are planted in the center of
the pit.
Choice of species:
Most suitable species are Acacia auriculiformis, Eucalyptus hybrid, Madhuca latifolia,
Pterocarpus marsupium shorea robusta, Dendrocalamus strictus, Xylia xylocarpa, Ptero carpus
santalinus and Tectona grandis have also done well. Hardwickia, Bombax, Gmelina, ouginia
are also considered suitable.
Unit : 2 Tree Improvement
Selection
• Choosing individual trees with desired qualities to serve as parents for next generation
• Objective is to obtain significant amount of genetic gain as quickly and inexpensively
as possible while at the same time maintaining a broad genetic base to ensure future
gains
• Selection is based on the principle that average genetic value of selected individuals
will be better than average value of individuals in the population as a whole
• Selection differential (S): Average phenotypic value of selected individuals expressed
as a deviation from the population mean
• With much phenotypic variation for a given characteristics, selection differential can
be large
• Plus tree: superior phenotype for growth, form, wood quality or other desired
characteristics. Not been tested for its genetic worth
• Significant in natural reseeding and are often used as seed sources
• Examples of characteristics showing relatively high heritability are wood specific
gravity, resin yields in pine, and most adaptability characteristics
17

18. Silviculture Note
• Straightness of tree bole, and disease resistance are intermediate whereas for most
characteristics related to growth, individual selection is less effective because of low
heritability
• G (Gain)= heritability x selection differential
• Heritability is generally quite constant for a given characteristics at a given age in a
given environment
• Selection differential can be manipulated by varying intensity with which selection is
applied
• For most characteristics, individual selection (superior phenotypes) should be followed
by progeny testing to determine if selected tree is in fact genetically superior
Selection methods:
1. Mass selection (individual selection)-choosing individuals on the basis of their
phenotypes without regard to information about performance of ancestors, offspring or
other relatives
• Works best for highly heritable traits, where phenotype is a good reflection of
genotype
• Usual practice in seed orchard where seed is mixed without concern for family
relations
• Only type of selection that can be used in natural stands or in plantations where tree
parentage is unknown
2. Family selection: Entire families selected on the basis of their average phenotypic
values. No selection of individuals within families
• Works best with traits of low heritability, where individual phenotype are not a good
reflection of genotype
• Rarely used in forestry
3. Progeny testing: Selection of parents based upon performance of their progeny. Very
precise selection method
• Not generally initial form of selection for most breeding programme
Selection from even-aged stands: Individual selection works
• Best when good even aged stands of proper age primarily of one species or in
plantations are available
• Trees should be average or better in growth, pruning, straightness, and other
characteristics of interest
• Superior trees should be located on same sites where plantations for improved seed
will be established
Selection from uneven aged, mixed stand: Forest stands are frequently not of types for
individual selection programme
• Reasons:1. Stands may be truly uneven aged 2. Desired species may so scattered that
comparison (check) trees are not available 3.Stand is composed of mixed species
• Comparision tree does not work when trees are growing in all aged stands and are
growing under different environment
Regression selection system is most useful for uneven aged or mixed species stands
• Regression selection system is built by sampling a no. of trees for a desired
characteristics, such as volume growth on a given site and then plotting them against
age.
• Different regressions developed for different sites. A reliable regression curve for
height or volume can be made with about 50 trees
• Trees falling above the curve should be chosen
• More difficult to use
18

19. Silviculture Note
Provenance Test
• Provenance: Geographical area from which seed or other propagules are obtained
• Provenance test: Collecting seeds of same species but from different locations
(geographic) and planting them at the same site
• To find best growth and survival and to quantify genetic variation
• Provenance test done for wide ecological and geographical range
• Species with wide geographical range contain more genetic diversity
Objectives:
1. planning breeding work
A. range of existing variation
B. Identify promising seed sources
2. Make planting recommendations
A. Best seed sources
B. Assess survival rate
3. Recommendations for seed from specific stands
A. Achieve best genetic gain by selecting best sources
B. To serve as seed orchard after sufficient data collection
Design:
1. Determine no. of populations to be tested and no. of locations where they will be tested
• Spp. with a small range-20-30 populations
• Spp. with large range-50-200 populations
2. Collect seed: through correspondence
• from several trees
• from average and best trees of population
3. Record and store collected information
• General information such as geographical location, elevation, collector’s name,
collection date
• Tree information: age, height of parent, branching habit
• Environmental factors: aspect, slope, soil properties, rainfall, temperature, wind,
sunshine
Site selection:
1. Sites requiring minimal preparation
2. Where test plots can directly be converted into plantations
• Provenance test for utis, sissoo (Nepal, Pakistan), khote sallo (Nepal, India, Pakistan)
and Eucalyptus have been conducted in Nepal
• Provenance test done on P. sylvestris, P. caribaea, Picea abies, Populus species, teak,
Eucalyptus, Seabuckthorn (China)
• In Canada provenance test established (for most commercial spp.) to stimulate effects
of climate change by studying northern seed that is moved to warmer southern climate
• IUFRO has done tests across countries
• International provenance trial of P. patula initiated in Nepal in 1982
• International provenance trial of Neem (in Nepal), P.kesiya and Acacia nilotica
• For Neem, 25 seed sources collected during 1995 and seeds collected from at least 25
trees with 100 metres apart
• Provenace test can provide mass propagation materials, breeding materials, help in
gene conservation, used for studies of genotype x environmental interactions
19

20. Silviculture Note
• Do not move trees from areas of uniform climate with small fluctuations in rainfall and
temp. to those with severe and large fluctuations, although annual average and
extremes may be similar
• Do not move high elevation or high latitude sources to low elevation or low latitudes
or the reverse. High elevation provenance from low latitude can often be moved to
lower Elevations at higher latitudes and vice versa
• Do not plant trees originating on basic soils on acid soils or vice versa
Seed Orchard
 Seed orchards are plantations of genetically superior trees, isolated to reduce
pollination from genetically inferior outside sources, and intensively managed to
produce seeds
 Established by setting out clones (as grafting or cutting) or seedling progeny of trees
selected for desired characteristics
 Ensures regular supply of trees
 In 1949, first pine seed orchard was planted in Sweden although this concept was
applied before 1940 to rubber trees
 Seed orchards of P. radiata (Australia and New Zealand), Teak (Thailand, Nigeria,
India, Papua New Guinea), Eucalyptus (Australia, S. Africa, Morocco, Portugal),
Amla, Harro, Barro (Nepal)
 Seed stand: A phenotypically superior stand selected to serve as a seed source before
genetic test can be performed
 1. Seedling seed orchard (SSO): Seed orchard from seedlings produced from selected
parents through natural or controlled pollination
 Preferred if a genetic test can be converted into a SSO, i.e. fulfilling both the testing
and seed production function at one time
 Necessary when there is incompatibility between scion and stock or other constraints
make vegetative propagation difficult
 Broader genetic base than Clonal seed orchard (CSO) but less selection differential
Testing on family level
Seed stand: A phenotypically superior stand selected to serve as a seed source before
genetic test can be performed
1. Seedling seed orchard (SSO): Seed orchard from seedlings produced from selected
parents through natural or controlled pollination
 Preferred if a genetic test can be converted into a SSO, i.e. fulfilling both the testing
and seed production function at one time
 Necessary when there is incompatibility between scion and stock or other constraints
make vegetative propagation difficult
 Broader genetic base than Clonal seed orchard (CSO) but less selection differential
 Testing on family level First flowering and fruiting usually occur later than CSO
 Very suitable for species like most eucalyptus, Black spruce (Picea mariana), early
flowering pines, and many hardwoods that produce seed at a young age
2. Clonal seed orchard (CSO): Seed orchard raised from selected clones propagated by
grafting, cutting, air-layering or tissue culture
 Preferred when vegetative propagation possible and seed orchard only serves as a
production area for seeds and/or vegetative propagules
 Narrower genetic base than SSO but higher selection differential
 Testing on individual level
20

21. Silviculture Note
 Generally first flowering earlier than SSO. Suitable for species with flowering delayed
for 10 to 20 years
3. Breeding seedling orchard (BSO): Seedling orchard used to preserve and test large
no. of genotypes, not to produce masssive quantities of seed for operational planting
 BSO of Dalbergia sissoo, Choerospondias axillaris established in Nepal
 Simple level BSO (Mass selection):
 Family identity not maintained
 Plantation at a close spacing (2m x 2 m)
 An equal no. of seedlings from each family (single tree selection) in a fully
randomised mixture should be planted
 Randomisation done prior to sowing, by mixing equal amount of seed from each
family
 Size minimum 2 ha
 Thinning done regularly until seed producing trees remain
 Seed orchard design:
1. Site should be selected for maximizing seed production:
 Climate and soil for high seed production
 Isolation from undesirable pollen sources
 Facility of access and nearness to work areas
2. Spacing of 6-10 m between trees
3. Isolation zone of at least 120 m wide around seed orchard to reduce pollen
contamination from other sources
 When trees are sufficiently mature for selection of plus progeny, poorer phenotypes
removed
 15 to 20 clones or trees needed (in general-60 to 100 clones practiced)
Seed orchard management:
 1. Soil 2. Weeding 3.Fertilization 4. Irrigation 5. Pest problems 6. Pruning 7. Thinning
8. Complete weather records (precipitation, relative humidity, temp., wind velocity,
wind direction)
 The design of BSO established for Artocarpus chaplasha (latahar) was Randomised
Complete Block Design (RCBD) with four blocks. Each block planted with 43
families of Jhapa provenance and 20 families of Ilam provenance. Each block has 63
plots and within each plot, one family was planted with 16 seedlings (Khadananda
Sharma. M.Sc. Thesis, 2006)
Unit : 4 Natural regeneration techniques
Introduction to silvicultural systems
Silviculture : The art and science of reproducing and growing trees and forests in a
sustainable manner based on principles of forest ecology for the benefit of society
Silvicultural systems are: The processes by which the crops that constitute a forest are
tended, removed and replaced by new crops, resulting in the production of woods of a
distinctive form.
Name of a system is based on:
• number of age classes (e.g. even-aged, uneven-aged), or
• regeneration method (e.g. shelterwood, selection)
A silvicultural system involves:
• method of regeneration (e.g. coppice, planting, natural regeneration, direct seeding)
• form of the crop produced (e.g. “regular” or “irregular”)
• arrangement of the crops over the forest (a form of “normality” usually aimed at)
21

22. Silviculture Note
Intensive versus extensive forestry
Features Intensive forests
Age distribution Even aged
Rotation Short (45-60 years)
Species composition Pure, exotic, clonal
Management Cheap
Establishment In open, by planting
Scale of operations Large, concentrated
Production 15-30 m3
ha-1
yr
Conservation value Low
Features Extensive forests
Age distribution 0 to rotation
Rotation Long (150-200 years)
Species composition Many, indigenous
Management Expensive
Establishment Under canopy, natural
regeneration
Scale of operations Small, scattered
Production 3-4 m3
ha-1
yr
Conservation value High
• The objective of a silvicultural system is to permit the harvesting of a mature timber
crop while providing space for the regeneration of the forest.
• Silvicultural systems are long-range harvest and management schemes designed to
optimize the growth, regeneration, and administrative management of particular forest
types for a sustained yield
Classification of Silvicultural Systems
Silvicultural systems have been classified in a variety of ways
The most commonly used classification is based primarily on the mode of regeneration
It is further classified according to the pattern of felling carried out in the forest crop
According to the method of regeneration silvicultural systems are of following two types
A. High forest systems:
Those silvicultural systems in which the regeneration is normally of seedling origin, either
natural or artificial or a combination of both and the rotation is generally long.
B. Coppice system:
Those silvicultural systems in which the crop originates mainly from coppice and the rotation is
short. The high forest systems and coppice systems are further classified on the basis of
pattern of felling and mode of regeneration as well. A schematic classification of these
systems is given here.
High Forest Systems
Systems of Concentrated Systems of Diffused Accessory Systems
Regeneration Regeneration
1.Two storeyed High Forest
22

23. Silviculture Note
2. High forest with
reserve
3.Improvement
felling
Clearfelling Shelterwood Systems Selection System
Systems
1. Clearfelling 1. Uniform system 1. Single Tree Selection
System. 2. Group ,, 2. Group Selection
2. The Clear Strip 3. Strip,,
System 4. Irregular ,,
3. The Alternate 5. Indian Irregular
Strip System. System
Coppice System (Low Forest System)
a. Simple Coppice System.
b. The Coppice of Two Rotation System.
c. The Shelterwood Coppice System.
d. The Coppice with Standards System.
e. The Coppice with Reserves System.
f. The Coppice Selection System.
g. The Pollarding
MAJOR SILVICULTURAL SYSTEMS
A. High Forest Systems:
1. The clear felling system:
The clear felling system is defined as a silvicultural system in which equal or equi- productive
areas of mature crop are successively clear-felled in one operation to be regenerated most
frequently, artificially but sometimes naturally also.
The area to be clear-felled each year in uniformly productive sites is l/n of the total area
allotted to this system.
N = no of years in the rotation and is usually referred to annual coupe.
The coupes to be felled every year are made equi-productive.
Removal or felling of mature crop:
According to definition, the entire crop of the coupe should be felled and removed in one
operation but in practices following variations are observed.
1. Retention of some mature trees as frost protection measures or as an insurance against
failure or as nurse crop to facilitate establishment of forest tender species.
2. Retention of promising groups of saplings and poles to prevent unnecessary sacrifice of
immature crop of the desired species.
3. Isolated saplings and poles are ordinarily not retained as they may develop in to wolf trees.
Methods of obtaining regeneration:
The area can be regenerated sometimes naturally but mostly artificially
Artificial regeneration is preferred due to following reasons
1.It is the surest and quickest method of improving crop composition.
23

24. Silviculture Note
2.It facilities introduction of fast growing and high yielding exotics.
3.It provides better financial returns.
4.The regeneration is established sooner, so the area can be opened for grazing sooner.
Method of Artificial Regeneration:
*Departmental plantation
*Taungia
Departmental Taungia
Leased Taungia
Village Taungia
Method of Natural Regeneration:
*Natural regeneration from seed
*Seeds stored in the area
*Seeds received from outside
*Natural regeneration from advanced growth
Variations in Clear-felling System:
* The clear strip system
* The alternate strip systems
*Clearfelling in patches
*Clearfelling with advanced regeneration
*Clear-felling with retention of sheltered
Advantages:
1. It is simplest of all high forest system. It does not require a high degree of skill.
2. As felling is concentrated, the yield per unit area is more and consequently the cost of
felling and extraction is low.
3. Introducing fast growing exotics and regulating composition of new crop through
artificial regeneration is advantageous.
4. It makes the supervision of all operations easy.
5. There is no damage to new crop by felling.
6. If properly tended the even aged crop produced have trees with cleaner and more
cylindrical boles.
7. Entire crop is regenerated in one operation. Its establishment is quicker there by
reducing the cost and rotation.
8. As the regeneration establishes early, the coupe can be opened up for grazing soon.
9. The distribution of age class is very regular.
10. The success or failure of regeneration is clear by the end of first year or in few years.
Disadvantages:
1. It is the most artificial system.
2. Soil remain open there is more danger of soil deterioration and erosion
3. The danger of weeds and grass invasion increases.
4. It produces even aged crop, which is less resistant to damage by wind.
5. when the crop is pure it becomes more susceptible to damage by Insects, plant parasites
and pathogens.
6. It sacrifices all immature crops that may still be putting on valuable increment.
7. Growing space and site factors are not fully utilized.
8. Annual yield is less than uneven aged crops.
9. This system is not suitable on hilly area and slopes.
24

25. Silviculture Note
10. The system is aesthetically very bad.
Seed Tree Method
In this method the stand is clear felled except for a few seed trees, which are left standing
singly or in groups to produce seeds for regeneration
After a new crop is established these seed trees may be removed or left indefinitely.
The chief distinction from shelter wood system is that the seed trees are retained only for seed
production and not enough to provide shelter.
On the basis of arrangements of seed trees the seed tree methods may be:
• Single Tree Method.
• Group Tree Method
• Strips or Rows Method
Characteristic of Seed Trees.
1. Wind firmness: Trees with tapering boles are more resistant to wind.
2. Seed producing ability: The best trees are members of Dominant crown class having wide
deep crowns and relatively large live crown ratio.
3. Age: Seed tree must be old enough to produce abundant fertile seeds, The age at which seed
bearing begins in closed stand is the safest criteria.
Number and Distribution of Seed Trees: It depends on following factors
*Amount of seed produced/tree
*The no. of seed required
*Seed Dissemination
*Number of viable seed produced (depend on pollination. There will be low no of viable
seed in isolated trees
*Seed germination
*Seedling establishment
Advantage: Ample opportunity for Phenotypic Selection, suitable for Light demanding
species.
Disadvantage: Under stocking, over stocking, damage by forest and drought.
Shelterwood Systems
Shelterwood system is a silvicultural systems in which the over wood is removed gradually
in two or more successive felling depending on the progress of regeneration.
In other words, the shelter wood system involves gradual removal of the entire stand in two or
more successive felling extending over a part of the rotation.
The trees, which are no longer capable of increment in value, are removed to make room for
regeneration to come in
The trees, which are growing vigorously, are retained to provide
(a) Shelter
(b) Seed
(c) Rapid diameter increment and value increment
(d) Protection of site against deterioration.
Kinds of Shelterwood system:
The varying patterns of regeneration felling and their distribution in space and time, results in
a variety of shelterwood systems.
1.Uniform shelterwood system:
Regeneration felling is done by making uniform opening
25

26. Silviculture Note
2.Group shelterwood system:
Regeneration felling is done in scattered groups
3.The shelterwood strip system:
Regeneration felling is done in strips
4. Irregular Shelterwood System:
Opening is made irregularly.
Uneven aged crop is produced
There is a compromise between shelterwood group system & selection system
5.Indian irregular shelterwood system:
Uneven aged crop is produced and immature trees are retained as future crop
It is a compromise between Uniform System and Selection System.
6.One cut sheltered:
Removal of over wood in one operation if sufficient advance growth is present
1.Uniform Shelterwood System (Uniform System)
The canopy is uniformly opened up over the whole are of a compartment to obtain uniform
regeneration. It is also called as shelterwood compartment system or compartment system.
Pattern of felling:
Preparatory felling: It is a felling made under a high forest system with the object of
creating conditions favorable to seed production and natural regeneration
*Create gaps in the canopy
*Create favorable conditions on the forest floor.
Seeding felling: It is defined as opening the canopy of a mature stand to provide conditions
securing regeneration from the seed of trees retained
This is the first stage of regeneration felling and the object is to make opening in the canopy
all over the compartment so that favorable conditions are created for regeneration.
There are two important considerations
1.Selection of trees to be retained:
*Genetically superior trees.
*The number of trees varies according to the silvicultural requirement of species.
*The shade bearing sp. and those with heavy seed-retain more seed trees (small opening)
*The light demanding sp. and those with light seed-retain less seed trees (large opening)
*For the same sp. opening is lighter in the drier areas than in moist areas.
*Seeding felling is done with caution if there is danger of invasion of grasses and weeds.
*Large no. of seed bearers on southern aspect and less no. of seed bearers on northern
aspect for the same species.
2.The number of seed bearers:
*The number of seed bearers to be retained depends on:
*Seed requirement of the area.
*Amount of light to be admitted (shelter)
*Moisture condition
*Condition of weed growth
*Altitude and aspect.
Examples:
26

27. Silviculture Note
Species No. of seed bearers Approx. Distance between trees
Pinus roxburghii 12-18 on cooler aspect 24-30m.
20-25 on warmer aspect 20-22m.
Pinus wallichiana 25-30 18-20m.
Cedrus deodara (Deodar) 45-50 14-15m.
Picea smithiana (Spruces) 45-50 14-15m.
Abies pindrow (Fir) 75-87 11-12m
Secondary felling: It is defined as a regeneration felling carried out between seeding felling
and final felling in order gradually to remove the shelter and admit increasing light
to the regenerated crop
Removal of trees in secondary felling depends on progress of regeneration and its light
requirement. It also helps in the manipulation of mixture of crop.
Final felling: It is defined as the removal of the last shelter or seed trees after regeneration has
been affected. It is the final stage in regeneration felling when there is completely
stocked with established regeneration which do not require shelter.
Advantages:
1. Marking and felling of trees of the over wood are simpler than in other shelterwood
systems as well as selection system.
2. In this system the soil is not completely denuded so there is little risk of soil deterioration
and erosion.
3. As the regeneration operations are carried out under the shelter of older crop, there is little
danger of invasion of the area by weeds and grasses.
4. The young crop is protected against adverse climatic factors such as cold, frost, winds,
drought etc.
5. As the regeneration is obtained from seeds obtained from best selected trees, the new crop
is superior.
6. It is a suitable system for the regeneration of both light demander and shade bearer
species. In mixed forest it is suitable to regenerate a mixture of different species by
regulating of light reaching on forest floor.
7. As the new crop appears before the old one is harvested, the average length of rotation is
shortened.
8. The growing space is more fully utilized as the regeneration grows under the shelter of
older trees.
9. It makes supervision and control of various operations easy.
10. From aesthetic point of view the system is superior to clear felling system.
Disadvantages:
1. As the over wood is removed in more than one operation there is much damage to the
young crop.
2. In mixed forest with species having different light requirement, the manipulation of
canopy requires skill and knowledge of silvicultural requirement of species composing the
mixture.
3. The isolated seed bearers are susceptible to wind damage.
4. In the species having long intervals between seed years, after seeding felling there may be
invasion by weeds and regeneration may be affected.
5. In species with longer regeneration period, weeding and cleaning has to be done for longer
period and the natural regeneration becomes costly.
27

28. Silviculture Note
The Group System:
Regeneration felling are carried out in scattered groups either because of presence of advance
growth or to induce regeneration de-nova so that there foci of regeneration can be enlarged
centrifugally to merge with each other ultimately.
Advantage:
1. The young crop develops in more natural way.
2. Adjoining trees protects the young regeneration.
3. Little danger of the seed bearers being uprooted by windstorm.
4. Less damage of young crop by regulating the fall of trees in unfelled areas.
Disadvantages:
1. Existing advanced growth has to be located which is difficult in hills.
2. Marking of seeding felling is difficult around group of advanced growth in hilly terrain.
3. The weeding and cleaning is difficult and costly.
4. As the work gets diffused its supervision and control becomes difficult.
5. Over extensive area, intensive working is not possible.
6. Requires individual attention of a single officer for about 30 years, which is not possible.
Shelterwood strip system: Regeneration felling are done in the form of strips successively
from one side of the compartment, progressing against the direction of wind.
The width of the strip varies according to local conditions, and may vary from 20 m to 30 or
even more.
Advantage:
(1) It provides protection from wind.
Disadvantage:
(1) Laying out of strips, execution of felling, logging, transport of material, tending,
protection against grazing and fire is difficult and not applied in India.
The Irregular Shelterwood System:
Regeneration felling is on the pattern of group system but as the regeneration period is long,
the crop produced is uneven aged or irregular. This is a compromise between shelterwood
group system and selection system.
Indian Irregular Sheltered System:
Silvicultural System is which the crop to be regenerated is open up irregularly and the
resultant crop is uneven aged, a compromise between uniform system and selection system.
1. It provides for retention of groups of well-grown poles and immature trees (upto 40 cm.
diameter) as the future crop.
2. It permits the adoption of selection felling on steep and rugged portion of compartment
being worked under uniform system.
The Selection System
The selection system is defined as a silvicultural system in which felling and regeneration are
distributed over the whole of the area and the resultant crop is so uneven-aged that trees of all
28

29. Silviculture Note
ages are found mixed together over every part of the area. Such a crop is referred to as selection
forest or all-aged forest. the selection system may be of following two types.
*Single tree selection
*Group selection
Felling of trees allover the area of a forest is possible when the area is small but if the area is
large it is not possible to fell the trees over the entire area annually. Therefore, the area to be
worked under selection system is divided in to coups and felling is confined to one coup every
year.
Ideal selection system
Periodic selection system
Thus, felling is done in a coup after a certain number of years, which is equal to the number of
coups. This interval is known as felling cycle, which is defined as the time between two
successive main felling on the same area. The length of the felling cycle affects the silviculture of
species, exploitation of forest, and the nature of crop produced.
Selection forest or all aged forest:
1. The felling and regeneration are distributed over the whole area.
2. Uneven aged - All aged.
3. Regeneration operations are carried out throughout the life of crop.
Conduct of felling: following categories of trees are generally removed.
(1) Dead, dying, diseased, misshapen or otherwise defective trees interfering with the growth
of better trees.
(2) Trees of undesirable species
(3) Immature trees, which can be removed in judicious thinning carried out in different age
classes.
(4) Mature tree of and above the exploitable diameter which will leave gaps for regeneration
to come in
(5) Maintain proper proportion of diameter classes – Maintain reveres ‘J ‘shaped curve.
29

30. Silviculture Note
Consideration for Application:
(1) Topography
(2) Catchment Areas
(3) Communication
(4) Market Requirement
(5) Silvicultural Considerations
Advantages:
(1) It results in the production of all aged forest. Trees of all ages are mixed together on each
unit of area. Then the growing space and site factors are fully utilized.
(2) By maintaining continuous leaf cover, the selection systems conserves soil and moisture to
the fullest extent possible.
(3) The selection forest produced is most resistant to injuries by insect pests and adverse
climate factors.
(4) It prevents invasion of grass and weeds.
(5) natural regeneration comes up without difficulty due to abundance of seed bearers, use of
every seed year and the protection afforded to seedlings.
(6) The forest regenerate itself continuously, without any time limit.
(7) As the lower age class trees grow below the older trees, the selection system results in
producing more growing stock in large size trees per unit area than the uniform system.
(8) This is best system of producing large size trees.
(9) It produces a forest which is superior biologically (Bio-diversity) as well as in its aesthetic
and scenic value.
Disadvantages:
(1) Considerable skill is required in carrying out marking and felling to ensure regeneration to
come up in the gaps. This requires knowledge of silviculture of species.
(2) As the mature trees to be removed are scattered, cost of logging and extraction is high.
(3) Felling, logging and extraction causes damage to the young crop.
(4) Seed is obtained from good as well as bad trees, there is genetic deterioration of future
crop.
(5) There is much damage to regeneration by grazing.
(6) As the area is extensive, strict fire protection is difficult. Thus accidental fires result in
damaging the new crop.
(7) Success or failure of regeneration is difficult to assess.
(8) In a mixed crop with lower % of valuable species, when valuable sp. are removed there
vacancies are filled up by less valuable species.
(9) Maintaining proper proportion of each diameter classes is very difficult and there will be
Misconception of Reverse J shaped curve.
(10)It is difficult to know exact growing stock, normal distribution of tree sp. and DBH.
(11)Heavy felling.
Coppice Systems
The silvicultural system in which the crop is regenerated mainly from stool coppice and with
short rotation. Reproduction is obtained from the shoots arising from the adventitious buds of
the stump of felled trees.
Types of coppice system:
On the basis of pattern of felling the coppice system is of various types.
30

31. Silviculture Note
1. Simple coppice system.
2. The coppice of two rotation system.
3. The shelterwood coppice system.
4. The coppice with standard system.
5. The coppice with Reserve System.
6. Coppice Selection System.
7. Pollarding
Factors affecting natural regeneration by coppice:
1. Species- coppicing power.
2. Age of tree-pole and young trees.
3. Season of coppicing-before spring.
4. Height of stump-15-25 cm.
5. Rotation-short.
6. Silvicultural system-clear-felling.
Simple coppice system:
The simple coppice system is defined as a silvicultural system based on stool coppice in which
the old crop is clear felled completely with no reservation.
Patter of felling in simple coppice system consists in clear felling a fixed area annually.
Area of coppice coupe = 1/n x total area. Where n is the number of years in rotation.
Season for coppicing:
1. The best season for coppicing is a little before the growth start in spring because at this
time there is a large reserve food material in roots which is utilized by the coppice shoots.
2. During the dormancy period. (from Nov. – Feb./March)
Method of felling:
1. the stump should neither be too low/high.
2. The lower the stump, the better it is for coppice shoot.
3. but if the trees are cut very low there is a danger of the stump splitting and or drying up
from top.
4. On the other hand, the higher the stumps, the greater the possibility of shoots being
damaged by wind or animals.
5. Stumps are usually kept, 15-25 cm high. (10 cm for eucalyptus)
Precaution during felling:
1. Stump should not split during felling trees.
2. The bark did not get detach from the wood.
3. Stump should slope slightly in one direction.
Tending:
Cleaning is done to remove climbers and inferior sp. and to reduce the no. of shoots to two or
three.
Thinning if necessary is carried out in fifth year and the no. of shoot is reduced to one/stool.
This is called as singling out operation for pole or timber.
Advantage:
1. The system is very simple and does not require any skill in making.
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32. Silviculture Note
2. The regeneration is more certain.
3. As coppice shoot grow faster in the beginning the cost of weeding, cleaning and protection
is much less than in case of reproduction by seed.
4. The mean annual increment (MAI) of the coppice crop is much higher then that obtained
under high forest.
5. The net returns on investment are relatively higher primarily due to short rotation and less
investment.
6. Although it is shortsighted system but very suitable for producing fuelwood and small
sized timber to fulfill the immediate need of the society.
Disadvantage:
1. The system tends to exhaust mineral substances in the soil.
2. This system is not permanent because the trees can not keep on coppicing indefinitely.
3. The coppice crop is liable to great damage by frost and wind.
4. This is not a very desirable system from aesthetic point of vies.
5. Risk of site deterioration (Soil erosion, weed invasion etc.)
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33. Silviculture Note
Coppice with standards system
It is silvicultural system based on coppice in which over wood of standards, usually of
seedling origin and composed of trees of various ages, is kept over coppice for a period of
multiple coppice rotation and as a permanent feature of the crop through out its life.
Purpose of standards:
1. Supply of large size timber
2. Protection against frost
3. Enrichment of coppice
4. To provide seedling regeneration
5. Increase in revenue
Thus, 1) Constitution of crop: lower storey (even aged coppice crop), upper storey (over
wood of standards).
2) Rotation: two rotation- one for coppice and one for standard (multiple of
coppice rotation).
Pattern of felling:
All trees except standards are clear felled and selection of standards depends on
1. Species:
The species of same or different sp. or a mixture of species.
2.Characteristics and quality of standards:
Standards should be as follow
1.most valuable species
2.long, clean bole with light foliage
3.capable of putting on increment and increasing in value
4.wind firm
5.light demanders
3.No. of standards:
Number of standards depend on following
1. Object of mgt.
2. Climatic factors (frost)
3. Silvicultural characteristics of species (light, frost etc.)
- Standards should not occupy more than one third of the canopy (33%)
- The space allotted to the standards is to be properly distributed amongst the various
age classes.
4. Distribution of standards: Uniformly distributed over the whole area.
If .3% of canopy area is occupied by standards and there are three age class present than each
age class will occupy 0.1% of canopy area. It means more no. of trees of lower age class.
Advantages:
1. There is greater protection to the soil.
2. Advantage of heavy shelterwood felling and selection system.
3. Standards serve as seed bearers and provide seed.
4. The investment is small and the net return is higher.
5. Aesthetically superior than simple coppice.
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34. Silviculture Note
Disadvantage:
1. It requires great skill in maintaining correct balance between standards and coppice and
between standards of different age classes.
2. This is a combination of simple coppice system and high forest system with the advantage
of none.
3. It has an exhaustive effect on soil.
4. Felling and extraction cost is higher than high forest system.
Conditions of Application of CWS:
1. Where there is demand of firewood, pole, and timber.
2. Where simple coppice is inhibited due to climatic factors and silvicultural characteristics
of species.
C.W. S. Not suitable for:
1. If required no. of standards of desired species are not available.
2. Poles of valuable species have to be coppiced immaturely which can produce large timber
if thinning is done.
3. It does not provide for retention of other trees for economic, silvicultural or protective
consideration, howsoever important and necessary these may be.
Example:
Forest Coppice rotation Standard rotation
1. Sal 30 years 60 years
2. Jamun belt 20 or 30 40 or 60
3. Dry deciduous forest 30 90
4. Anogeissus pendula 40 80
FORMULATION OF SILVICULTURAL SYSTEMS
A good silvicultural system is a long-term program of treatment designed to fit a specific set
of circumstances
It is not likely to be something that has already been invented and can simply be selected from
schematic description of silvicultural systems given in books
In fact there is no cookbook for the application of silvicultural systems. A silvicultural system
evolves over time as circumstance change and knowledge of them improves.
Formulation of a silvicultural system should start with the analysis of the natural and
socioeconomic factors of the situation
If silvicultural systems are not chosen readymade from a manual or book, it is logical to
examine the various considerations that enter in to their construction and evolutionary
development
In the first place, a rational silvicultural system for a particular stand should fit logically in to
the over all management plan for the forest of which the stand is a part
Second, it should represent the best possible amalgam of attempts to satisfy all the following
major considerations.
Considerations:
1.Hormony with goals and characteristics of ownership
2.Provision for regeneration
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35. Silviculture Note
3.Efficient use of growing space and site productivity
4.Control of damaging agencies
5.Provision for sustained yield
6.Optimum use of capital and growing stock
7.Concentration and efficient arrangements of operations
8.Resolution of conflicting objectives
Natural Regeneration
Natural regeneration is defined as the renewal of a forest crop by self-sown seed or by coppice
or root suckers.
It also refers to the crop so obtained.
The natural regeneration can be obtained from the following two source.
1.Natural Regeneration from Seed
2.Natural regeneration from vegetative parts(Coppice)
Natural Regeneration from Seed:
Natural regeneration from seed depends on the following
Seed Production
Seed Dispersal.
Seed Germination
Seedling Establishment
A. Seed Production:
The most important consideration for natural regeneration from seed is the production of
adequate amount of fertile seeds by the trees of the area or in the vicinity. The production of
seed depends on the following
Species, Age of trees, Size of Crown, Climate, and other external factors
1.Species:
All species do not produce seed annually and abundantly.
Some species like Teak, Acacia, and Sissoo etc. Produce seed annually.
While Deodar, Fir and Spruce etc. seed at an interval of years.
The quantity of seed produced by annual seeders varies. This variation in seed production is
the seeding periodicity
Depending on the amount of seed produced, seed years are described as Good, Moderate, or
poor
Moderate and Good seed years of some important species is mentioned as follows.
Species Moderate Good
Seed years Seed years
Shorea robusta 2 3-5
Terminalia tomentosa 2 3-4
Pinus wallichiana 2 2-3
P. Roxburghi 3 4-5
Cupressus torolosa 3 7-8
Cedrus deodara 3 4-5
Picea smithiana 3 5-6
Abies pindrow 6 10
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36. Silviculture Note
2. Age of Trees:
The age of trees also affects the production of adequate amount of fertile seeds
The seed produced by immature and over mature trees are sometimes infertile
Abundant amount of fertile seeds are produced from middle aged trees. Abundant amount of
fertile seeds is produced by the trees when height growth is culminated and during this period
carbohydrate produced is translocated to seed formation.
3. Size of Crown:
The size of the crown of trees also affect seed production
As a general rule, the bigger the crown, the larger the seed production
4. Climate:
Climate also affects the seed production. As a general rule warmer climate favors larger seed
production
Hot dry airs are generally followed by heavy seed years on account of increase in
Photosynthesis
Heavy rainstorms at the time of pollen dissemination reduce chances of pollination and good
seed production
Late frost adversely affects seed production.
5. Other external factors:
Injury by fire and insect attack reduces seed production by damaging the crown
If the damages are only concentrated on barks then it stimulates seed production by
transporting carbohydrate to the seeds and not to the roots
Girdling also favors heavy seeding due to same reason.
B. Seed Dispersal:
The seed produced by the trees is dispersed by the agency of wind, water, gravity, birds and
animals. Some examples of seed dispersal by various agencies are given below.
Wind: All conifers and several dicots (Acer, Betula, Populus, Alnus , Salix Terminalia,
Dalbrgia, Acacia , Adina and Bombax.
Water: Mangrove , Dalbergia, and Teak.
Bird: Prunus, Mulberry, and Diospyrus
Animals:Acaica arabica, Prosopssis juliflora, Zizyphus, and Anthocephallus.
Gravity: Oak, Juglans, and Asculus.
C. Seed Germination:
After dispersal insect birds and rodents destroy a lot of seeds. The others germinate provided
they are deposited on suitable soil. Germination of seeds depends upon several internal and
36

37. Silviculture Note
external factors listed below.
Internal Factors:
Permeability to water
Permeability to O2
Development of embryo ( ie.Frixinus floribunda takes one year)
After ripening (ie.Juniperus macropoda)
Viability of Seeds
Size of seeds
Germination capacity
Germination energy
External factors:
Moisture
Air
Temperature
Light (ie. Cassia fistula or Albizzia procera requires light)
Seed Bed
D. Seedling establishment:
Even if germination is good it does not mean that natural regeneration would be good,
because a large number of seedlings die at the end of rains or as a result of frost during winter
or drought during summer. In addition there may be other factors such as weeds, grazing, fire,
which may kill them.
Thus, establishment is defined as the development of new crop ‘naturally or assisted’ to a
stage when the young regeneration ‘natural or artificial’ is considered safe from normal
adverse influences and no longer needs special protection or tending operation other than
cleaning, thinning, and pruning.
The following factors affect establishment of seedlings.
1.Development of root
2.Soil condition
3.Moisture
4.Aeration
5.Nutrients
6.Light
7.Temp.(Frost, Drought)
8.Rainfall.
9.Drip (Slash erosion)
10.Condition of grasses and other competing weeds
11.Grazing, Browsing and Fire
12.Composition of the crop
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38. Silviculture Note
Natural Regeneration Techniques
1. Seed Supply
2. Soil condition
3. Light requirement
4. Burning
5. Slash disposal
6. Weeding
7. Cleaning
8. Protection
Seed Supply
Clear felling System:
i. From adjacent stands
ii. Seeds already lying dormant on the site
iii. Ripe seeds on the mature tree before felling
iv. Advanced growth already present in the area (site)
Shelterwood System:
The number of seeds required depends on the species
Adina cardifolia 1-2 trees/ha
Shorea robusta 30-40 trees/ha
Pinus roxburghii 12-18 trees/ha on cooler aspect
Pinus roxburghii 20-25 trees/ha on warmer aspect
Pinus wallichiana 25-30 trees/ha
Cedrus deodar 45-50 trees/ha
Picea smithiana 45-50 trees/ha
Abies pindrow 75-87 trees/ha
Selection System:
Abundance of seed bearers and use of every seed year
Light Requirement
Light affects the soil conditions, undergrowth, and seed germination, so adequate light
should reach the forest floor. This is achieved by manipulation of canopy. The requirement
of light varies with species and their variation in light requirement in different conditions
and at various stages of their development.
Light Demander: Pinus roxburghii, Pinus wallichiana, Populas cilliata, Shorea robusta,
Tectona grandis, Dalbergia sisso, Adina cardifolia, Bombax ceiba, Quercus incana etc.
Shade Bearer: Picea smithiana, Cedrus deodara, Cupressus torulosa, Quercus glauca,
Toona cilliata, Dalbergia latifolia, Petrocarpus marsupium, Artocarpus sp.
Shade Demander: Abies pindrow, Taxus buccata, Mallotus phillippinensis, Litsea
glutinosa, Syzizium cumini
Light is very important factor in seedling establishment but its requirement varies from
species to species and even in the same species according to climatic conditions and age.
i.e. Teak seedlings must have sufficient light but in dry localities seedlings require
protection from sun.
Sal is able to persist in moderate shade in the beginning but it needs complete overhead
light later.
Soil Condition
Soil moisture affects regeneration. Permeable and non compacted soil is better .
38

39. Silviculture Note
Aeration also affects regeneration. Poor drainage, water logging adversely affects seedling
growth and regeneration
Nutrients: Un-decomposed organic matter thick layer of partly decomposed leaves
adversely affect regeneration.
Control fire (control burning)
Controlled burning is used as a tool to obtain natural regeneration in certain types of Sal,
Chir and Teak forests.
Sal Forest: In the very moist and moist sal forest annual and periodic burning is used to
reduce the density of shrubs and soil moisture and to burn leaf litter to provide clean seed
bed for natural regeneration.
Burning is harmful in dry types of Sal forest.
In Pine Forest controlled burning is done before carrying out seeding felling.
Burning destroys needles and shrubs and provides clean bed.
After a good seed year burning is not done.
The controlled burning is again done when the natural regeneration has reached a size that
the area is to be put outside the regeneration area.
So, before carrying out final felling, the natural regeneration is controlled burn for three
years to harden the natural regeneration against accidental fire. (November or December is
suitable for control burning.)
Teak forest: In moist teak forest controlled burning induces regeneration and suppresses
weeds.
Slash disposal
Felling of trees for canopy manipulation or timber harvesting results in leaving large
quantities of slash in the regeneration area. This has to be removed to make the area clean
for seed germination as well as to reduce the hazards from fire, insect and fungi.
1. Slash in relation to forest fire.
2. Effects of slash on regeneration.
3. Effect on soil (decomposition of slash onsite)
4. Slash in relation to insects and fungi
5. Slash in relation to Aesthetics and wildlife.
Methods of Slash disposal:
1. Broadcast burning of slash.
2. Spot burning
3. Lopping and scattering of slash
4. Clipping and Yarding of slash.
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40. Silviculture Note
Unit : 5 Silvicultural management of forest (application of silvicultural systems)
Classification of silvicultural systems
1. coppice systems
2. high forest systems
a) regeneration over whole forest which is uneven-aged polycyclic or selection systems
b) regeneration concentrated in one part of forest at any one time
i) old crop removed in several fellings over years shelterwood systems
ii) old crop removed by a single felling monocyclic or clear felling system
Intensive versus extensive systems
Intensive (monocyclic) systems
coppice
coppice with standards
clear felling
(shelterwood)
Extensive (polycyclic) systems
selection
group systems
Application of coppice systems
• Where small dimensioned material is required (fuel wood Salix and Populus, pulp
Eucalyptus)
• Generally only with broadleaved trees
• Where some forms of nature conservation are important
• Formerly for basket willows, farm and household implements, etc
Application of selection systems
• On steep sites for protection against soil erosion and avalanches
• Where landscape continuity is required (urban forests)
• Where wood production and profit are not major motives
• Mainly appropriate for shade bearers (beech and silver firs)
Application of shelterwood systems
• Usually on rather similar sites to clear felling—where soil deterioration is not a serious
risk
• In environments where species grown produce viable seed regularly (oak and beech in
parts of Europe, sycamore and ash in UK, Dipterocarps in SE Asia)
Application of clear felling system
• On sites where forest clearance will not cause erosion or other problems
• Where profit is a major motive for planting
• With light-demanding species that have evolved in monocultures (often pines, spruces,
eucalypts)
Choice of system depends on:
Regeneration ecology of trees
Site, topography, soil
Wildlife
Pests and diseases
Fire
Climatic risks
Size, age, vigour of existing stand
Introduction of new genotypes
40

41. Silviculture Note
Financial constraints
Silvicultural Systems Applicable to Important Species
It is not wise to recommend any particular silvicultural system for a species. In fact
silvicultural systems for a particular forest stand should be formulated or selected on the basis
of important silvicultural characteristics of the species, forest condition, forest owner’s
objective of management, and several other consideration described earlier. However, looking
on the important silvicultural characteristics and other considerations some of the important
silvicultural systems, which may be applicable for different forests in various circumstances is
prescribed here.
Sal (Shorea robusta):
Silvicultural Characteristics:
1. Strong Light demander
2. Good coppicer (stems up to 20-30cm in diameter)
1. Seedling die back due to frost, drought, fire, and dense overstorey
2. Annual seeder but good seed years after every 2 years
5. Light winged seeds and seeds dispersed by wind
Silvicultural Systems:
1. Selection system (group selection)
2. Irregular shelterwood system
3. Uniform shelterwood system
4. One cut shelterwood system
5. Clearfelling system (plantation by Taungia)
6. Coppice with standards
7. Coppice with reserves
8. Simple coppice
Khair (Acacia catechu):
Silvicultural characteristics:
1. Strong light demander
2. Seedlings are susceptible to severe frost
3. It is very drought resistant
4. It coppices well unless it is under shade of other species
5. Seeds produced in abundance
6. Seeds dispersed by wind and water
7. It requires protection from grazing and browsing
Silvicultural systems:
1. Clearfelling and plantation
2. Simple coppice
3. Coppice with standards
4. Seed tree method
Sisso (Dalbargia sissoo):
Silvicultural characteristics:
1. It is strong light demander
2. It is good coppicer
41

42. Silviculture Note
3. Annual seeder and seeds produced abundantly
4. Seeds dispersed by wind and water
5. Older seedlings can tolerate mild frost
6. It should be protected against grazing and browsing
Silvicultural systems:
1. Seed tree method
2. Cleaerfelling and plantation by Taungia
3. Two storeyed high forest system
4. Simple coppice
5. Coppice with standards
6. Coppice with two rotation system
Khair and Sisso (Acacia catachu and Dalbergia sissoo):
Silvicultural systems:
1. Coppice with standards
2. Coppice with two rotation
3. Seed tree method
4. Clearfelling and plantation
Chilaune (Schima wallichii):
Silvicultural characteristics:
1. Moderately shade tolerant but later it benefits from full overhead light
2. It is capable of colonizing plantations of other species
3. It is not frost hardy
4. It coppices very well
5. Good seed year are frequent
6. Winged light seeds dispersed by wind
Silvicultural systems:
1. Simple coppice
2. Coppice with two rotation
3. Coppice with standards
4. Selection coppice
5. Selection System
Katus (Castanopsis species):
Silvicultural characteristics:
1. Moderately shade tolerant
2. It benefits from overhead light in later stage
3. It is frost hardy(C. Hystrix)
4. Young seedlings are frost tender(C. Tribuloides)
5. It coppices well
Silvicultural systems:
1. Simple coppice
2. Coppice with two rotation
3. Coppice with standard
4. Selection coppice
5. Selection System
Asna (Terminalia tomentosa):
42

43. Silviculture Note
Silvicultural characteristics:
1. It is light demander
2. Seedlings can withstand moderately side shade but are killed by heavy shade
3. Seedlings are often killed back by frost
4. The tree is fairly tolerant to fire damage
5. It coppices well(up to 40cm. in diameter)
Silvicultural systems:
1. Single tree selection
2. Coppice with standards
3. Coppice with reserves
4. Shelterwood system
Oaks (Quercus species):
Silvicultural characteristics:
1. Tolerate shade when young
2. Seedlings are very shade tolerant(Q. incana)
3. Early frost kills seedlings
4. Seedlings frost resistant(Q. lamelosa and Q. semicarpifolia)
5. Growth of older trees is better in the open
6. It coppices well but above 10cm. diameter coppicing power reduces(Q. floribunda)
7. Seeds (Acorns) are large and have limited distribution by gravity
Silvicultural systems:
1. Simple coppice system
2. Coppice with standards
3. Coppice with two rotation
4. Selection coppice
5. Uniform shelterwood system
Chirpine (Pinus roxberghii):
Silvicultural characteristics:
1. Strong light demander
2. Seedlings require full overhead light
3. Seedlings are reasonably frost hardy
4. It is very fire resistant species
5. Seedlings over one year old killed by fire will send up new shoots
6. Abundant seed production but good seed years come after every 4-5 years
7. Seeds are light and dispersed by wind
8. Certain ability to coppice when small trees are felled but it is of little importance
Silvicultural systems:
1. Seed tree method
2. Uniform or irrefgular shelterwood system
3. Group selection
4. Clearfelling with advanced regeneration/One cut Shelterwood
Bluepine (Pinus wallichiana):
Silvicultural characteristics:
1. Strong light demander
2. Seedlings are frost hardy
3. Less fire resistant than P. Roxburghii
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44. Silviculture Note
4. Small seedlings may suffer from drought after and before mansoon
5. Seedlings will persist for some year under moderate shade but for good development full
light is needed
6. It regenerates profusely where conditions are favorable
7. Abundant seed production but good seed years come after every 2-3 years
8. Light seeds and seeds dispersed by wind fairly to large distance up to 200m or more
Silvicultural systems:
1. Seed tree method
2. Uniform or irregular shelterwood system
3. Group selection
4. Clear felling with advanced regeneration.
Fir (Abies species):
Silvicultural characteristics:
1. It is highly shade tolerant
2. Prefer cool moist habitat
3. Tolerant to frost and snow
4. Very sensitive to fire
5. Seeds dispersed by wind(winged seeds)
6. Good seed years after every 3-4 years in A. Spectabilis and about 10 years in A. Pindrow
Silvicultural systems:
1. Single tree selection
2. Irregular sheterwood system
3. Uniform shelterwood system (75-87 seed trees/ha.)
Spruce (Picea smithiana):
Silvicultural characteristics:
1. Shade bearer
2. Seeds dispersed by wind
3. Young seedlings do not suffer from frost
4. More of a pioneer often associated with blue pine
Silvicultural systems:
1. Single tree selection
2. Irregular shelterwood system
3. Uniform shelterwood system (45-50 seed trees / ha.)
Deodar (Cedrus deodara):
Silvicultural characteristics:
1. Shade bearer and young seedlings benefit from side shade
2. Winged seeds dispersed by wind
3. Young seedlings do not suffer from frost
4. Very sensitive to fire
5. Good seed years after every 3 years
6. Most of the seeds fall close to the parent tree
7. Profuse regeneration in favorable sites
44

45. Silviculture Note
Silvicultural systems:
4. Single tree selection
5. Irregular shelterwood system
6. Uniform shelterwood system (45-50 seed trees / ha.)
Impacts of Silvicultural Systems
• Disturbance in the Forest Ecosystem
• Disturbance f rom Simple to Catestrophic
• Harvesting of Carbon Stock from forest
• Site deterioration and Soil Erosion
• Nutrient loss and Nutrient leaching
• Biodiversity
• Wildlife habitat & Wild life population
• Aesthetic and Scenic values
Impact of Clearfelling System with artifical Regeneration
• High disurbance in Forest ecosystem
• Danger of site deterioration & soil erosoin
• More Nutrient loss & Nutrient leaching
• Negative impact on Biodiversity
• Heavy Destruction of wldlife habitat
• Migration of wildlife population
• Bad in aesthetic and scenic value
Clearfelling with natural regeneration OR Seed tree System
• High disturbance in Forest ecosystem
• Danger of site deterioration & soil erosoin
• Some Nutrient loss & Nutrient leaching
• Negative impact on Biodiversity
• Destruction of wldlife habitat
• Migration of wildlife population
• Not good in aesthetic and scenic value
Impact of Shelterwood System
• Less disturbance in Forest Ecosystem
• Little risk of Site deterioration & Soil erosion
• Less destruction in wildlife habitat
• This System is superior from biodiversity and aesthetic point of view
• Some Reduction in wild life habitat
• Some migration of Wildlife Population
Impact of Selection System
• Least disturbance in Forest Ecosystem
• Least risk of Site deterioration & Soil erosion
• Least disturbance in wild life habitat
• Wild life is not much affected. Group Selection is even better for some wildlife
• Forest produced is superior from biodiversity and aesthetic point of view
Impact of simple coppice system
• Much disturbance in forest ecosystem
• Risk of site deterioraion & soil erosion
• It has an exhastive effect on soil nutrients
• Destructin of wildlife habitat
• Some reduction and migration of wilfdlife
• Reduction in biodiversity
45

46. Silviculture Note
• Not good in its aesthetic and scenic value
Impact of Coppice with standards
• Less disturbance in the ecosystem
• Less destruction of wildlife habitat
• Very little chance of site deteriration, soil erosion, nutrient loss & nutreient leachng
• It has an exhastive effect on soil
• Least effect on biodiversity & wildlife
• System is superior in its aesthetic & scenic values
Impact on Soil Erosion
– Potential erosion problems include:
• Soil loss
• Stream sedimentation
– Roads & skid trails are the prime culprits
– Erosion reduced by
• Good road design & implementation
• Use of appropriate equipment
• Skylines, helicopters minimize erosion
Impact on Nutrient Loss
Nutrients can leach from forest operations sites
– Nutrient loss accelerated by:
• Short rotations
• Even-aged silvicultural systems
• Whole-tree harvest
– Nutrient loss mitigated by:
• Long rotations
• Uneven-aged silvicultural systems
– Net effects unclear -- need more research
Unit : 6 Quantitative Silviculture
• Growth: Irreversible increase in mass weight or vol. of a living organism, organ or cell
• Growth – Increase in size overtime
• Size increase must be permanent
• Often a growth curve can be fitted with a simple mathematical function, i.e. a straight
line or a simple S-shaped curve (Sigmoid curve)
• Early vegetative growth in herbaceous plants tends to be exponential curve although a
sigmoid pattern is more characteristics of its entire life span
Phases of growth
1.Logarithmic
2.Linear
3. Senescence
Logarithmic Phase
• Size increases exponentially with time
• Growth rate slow at first but continuously increases
• Growth rate proportional to size of organism
• Example: Single cells (Bacteria or yeast)
• Analogy between logarithmic phase and growth of money to draw compound interest
(Embryo: Initial capital, Photosynthetic efficiency: Determines interest rate)
Linear Phase
• Increase in size at a constant, usually maximum rate for some time (Hardly detectable)
Senescence phase
46

47. Silviculture Note
• Decrease in growth rate as the plant reaches maturity
Relationship between Growth and Time
• Wt=W0(1+r)**t where Wt=Total weight after certain time
• W0=Initial weight, r=interest rate, t=time period
• lnWt=lnW0+rtlne: Equation of a st line
• Slope of this line determined by r, rate of interest and represents plant’s capacity to
add to its own dry weight
• Y=bx**k: Exponential model,
• lnY=klnx+lnb: Growth allometric (Y=wt., x=time)
• Blackman (1919) used the term efficiency index to denote growth concept as relative
growth rate (RGR) or r
• From previous eq. lnWt=lnW0+rt (lne=1, e=2.7182)
• r=lnWt-lnW0/t, RGR=lnW2-lnW1/t2-t1 for two time periods t1 and t2 or RGR=1/W
dw/dt , that is, increase in weight/unit of original weight over a time interval t
Four concepts developed for use in growth analysis
1. Relative growth rate(RGR)
2. Leaf-area ratio (LAR)=L/W=L1+L2/W1+W2
(Ratio of leaf area to L to plant dry weight W)
3. Unit leaf rate (Or Net assimilation rate, NAR)=
(W2-W1)/{(L2-L1) (lnL2-lnL1)}
(that is, rate of increase in dry wt. Per unit leaf area, assuming that both are increasing
exponentially)
Represents photosynthetic efficiency
4. Relative leaf growth rate (RLGR)=lnL2-lnL1
Growth of a plant community
• Growth of a single plant can be usefully analysed in terms of dry matter
increment/unit time and as a function of leaf area, that is, NAR
• Community or crop growth cannot be adequately described in same terms
because factors beyond NAR help determine total dry matter production
• Photosynthetic rate of individual leaves will tend to be reduced due to mutual
shading
• Crop Growth Rate (CGR)={1/L}* {dw/dt} where L=ground surface
• CGR represents total dry matter productivity of community per unit land area
over a certain time span
• LAI (Leaf Rea Index)=A/L (ratio of leaf area to ground area)
• CGR=NAR x LAI= 1/A* dw/dt* A/L=1/L*dw/dt
47

48. Silviculture Note
References
• Plant growth and development-Leopold and Kriedemann 1981
• Plant physiology-Salisbury and Ross 1986
• Physiology of flowering plants-Street and Opik 1986
Models of Tree Mortality
• Trees die when they cannot acquire or mobilize sufficient resources to recoup from
stress, heal injuries or sustain life, or they are killed by some external factors
(insects, fungi, wind, lightning etc)
• Competition, senescence and external factors-reasons for tree mortality
• Age-independent mortality (Intrinsic mortality)
• Mortality that can happen at any time in the lifetime of a tree by factors such as
lightning strikes, falling trees and branches, animal browsing or girdling, insect
attack, fungal infection
• Assumption that chance plays a major role (Gap models use this assumption)
• Constant probability of death throughout lifetime of a tree, usually ending with 1 to
2% of all trees of a spp. Surviving to their maximum known age
Mi=(1-∑i)**AGEMxi
Where Mi=Prob. that a tree species i at age 1 will reach the maximum age
AGEMx=Maximum age that an individual of species i should be able to reach
∑i=Annual probability of death
Growth –dependent mortality
Assumption that growth rates below a specified threshold will predispose trees to insects
and disease attacks (i.e. slowed growth leads to probability of mortality)
Three or more consecutive years of below threshold growth (i.e dbh) due to some stress or
other factors make the trees vulnerable to higher mortality rates
Reference: Keane, R. et al. 2001. Tree mortality in Gap models. Kluwer Aademic
Publishers
48

49. Silviculture Note
Stand Dynamics
• Stand: A reasonably homogenous unit of trees that can be clearly differentiated by its
age, composition, structure
• The dynamics of stands are based on ecological principles: succession, competition,
tolerance
• Forest ecosystem: complex of biotic and abiotic factors and their relationship
• Such a complex never does and never can reach balance and permanence
• Constantly changing both in space and time (Dynamic)
• Changes of forest ecosystem in time: Diurnal changes (Night and day: temp.
difference and CO2 intake and O2 release)
• Seasonal changes (climatic changes around a year/during some period)
• Plants, animals that constitute the ecosystem biota never remain the same for more
than a given instant of time (Evolution necessary)
• Continual introduction of new species and elimination of old
Changes of ecosystem in space
• Forest ecosystem high in mountains will be different from those in lowlands
• Even on level ground, ecosystem will vary from north to south, east to west
• There is no such thing as a climax community in the sense of a permanent, stable
condition: Change is perpetual
• Self-thinning rule: As plants die remaining individuals become larger, smaller plants
continually eliminated from the population
• Strong relationship between plant size and density of stand
• Larger size and weight of biomass of stand associated with fewer stems/unit area
• Relationship: logw¯=a+blogp where w¯=mean wt. Of surviving plants, p=density
• Japanese workers examined thinning in overcrowded populations of several spps. Such
as radishes, soyabean and maize and also on pure stands of Amaranthus retroflexus,
Chenopodium album, Plantago asiatica on soils of varying fertility
Japanese researchers found a definite relationship between density of surviving plants
and their mean weight
• A single line with the slope of –3/2 represented maximum plant size –density
relationship regardless of age
• This relationship is called 3/2 power law for self thinning
• This relationship is reported to be valid for stands of any species, of any age or any site
References:
• Yoda et al. 1963. J.Biol. Osaka city univ. 14: 107-129
• White and Harper 1970. J.Eco. 58:467-485
• Drew and Flewelling 1977. For. Sci. 23 (4): 517-534
• Lonsdale and Watkinson. J.Ecology. 1983. 71:285-297
Competition
• Changes in structure and composition of forest result from demand of individual tree
for more space and from death of even most dominant individuals
• Competition between trees of same spp. does not affect composition of forest type and
has no effect on forest succession
• Competition between individuals of different species results in natural succession from
one forest composition to others
• Root competition is often severe in even-aged stands. In even aged stands, competition
for light, moisture and nutrients depend largely on number of stems/ unit area
49

50. Silviculture Note
• Vertical structure: result of competition among plant species of the forest
• Forest stand exhibit several major vertical layers: trees, shrubs, herbs, thallophytes
(mosses, lichens)
• Mortality is caused by competition among and between trees and associated vegetation
for light, water, nutrients and other site resources
• Competition is of two types: 1. Intraspecific
• 2. Interspecific
• Intraspecific: Competition among individuals of same spp
• Interspecific: Competition among individuals of different spp.
• Intraspecific: competition is important for the growth and health of individuals of
same spp.
• The nature of competition in even aged and un-even aged stands vary considerably.
• In even aged crops, competition for light, moisture, nutrients, growing space etc.
depends largely on stocking
• If roots and crowns do not close, there may be a little or no competition
• Physically, two types of competition become evident in even-aged pure crops-crown
competition and root competition
• In even aged crop, every individual has the same opportunity to grow and develop. But
in crops having intense competition, crown differentiation is evident
• Dominant trees receive full light from the above and partly from the sides. Dominated
trees receive some direct sunlight from above but very little from sides. Suppressed
trees remain entirely below canopy level and receive no direct light from above or
sides
• Root competition is also severe in even aged stands. The differences in root and crown
competitions are:
• 1. Crown competition is more visible than root competition
• 2. Crown competition is limited to only a few adjoining trees but root competition
takes place within a large no. of trees
• Root competition is more important during early periods of growth while crown
competition becomes important when formation of crown in trees take place.
• The nature of competition in uneven aged pure forests is different than even aged
forests.
• Older trees are well established and usually exert tremendous adverse effect on growth
of seedlings. The seedlings are able to grow in open patches. In some species, younger
trees persist for longer periods under the older trees and when older trees die or are
removed younger trees get a chance to develop.
• Inter specific competition: Competition in forests having different spp. of different
ages is more complex than intra specific competition
• In such forests, several vertical layers exist which are formed due to height variations
in trees, shrubs, herbs, grasses, mosses, lichens etc.
• In multi-layered or multi-storied forest, the top layer or storey is occupied by trees of
dominant class, second layer may consist of smaller trees of top layer.
• There can be a third layer predominantly occupied by shrubs and younger trees of first
and second layer
• There may be herb and grass layers
• In these forests, the spp. in each layer are genetically suited and adapted to
environmental conditions and make the best use of site factors, e.g. light, soil, water,
space, etc.
50

51. Silviculture Note
• The top layer intercepts a large quantity of incoming radiation. Usually, top layer does
allow some amount of solar radiation to lower canopies because 1. Top layer is often
broken 2. Trees in top layer may have light crowns.
• Second layer is also likely to get enough solar radiation
• The shrubs, herbs and other vegetation are adapted to grow in diffused light conditions
or lesser light conditions
• Competition in top layer: Some of the important characteristics which enable species
to maintain itself in top layer include
• 1. Faster growth rate 2. Vigorous branching habit to make fuller use of height 3.Shade
tolerant during initial years 4. Faster recovery from injuries
• Competition in lower layers: The nature of competition in lower layer in forests is
more complicated than top layer
• In lower layer, there are smaller trees, shrubs, herbaceous plants, etc which compete
among themselves.
• One of the important factors in deciding the ability of plants to survive and grow is
their shade tolerance or light requirements
• Several species in lower layers have been found to be adapted due to lower respiration
rates
• They are slow grown due to slow photosynthetic rates
Unit : 7 Urban Forestry
Urban Forestry aims at raising and management of trees and green areas in urban and
semi-urban centre.
Urban forestry includes the following:
1. Management of municipal lands
2. Management of watersheds in urban areas
3. Wildlife habitats
4. Opportunities for outdoor recreation
5. Landscape design
6. Recycling of municipal wastes
7. Tree care
8. Production of forest foods and services
Urban forestry includes green belts, parks and gardens, zoological parks, forest reserves,
avenues
Effects of urban forests on environment
1. Air quality improved: absorption of air pollutants by leaves or soil surface
-Deposition of particulates and aerosols on surface of leaves
-Sulphur di-oxide of air absorbed by trees
2. Moderation of temperature: Helps in controlling extremes of temperature
-Provide shade that reduces solar radiation
-Plants absorb heat as they transpire
3. Noise reduction: Noise levels reduced due to trees
4. Micro-climate amelioration: Micro-climate is ameliorated so that extremes are lowered
5. Fauna: Trees and other forms of vegetation harbour various faunal species which add to
the quality of life in urban areas
6. Erosion control
7. Landscape aesthetics: Landscape aesthetics of plants are
Becoming more highly valued
Arboreconomics: Monetary aspects of urban forestry- cost, assessing financial benefits,
estimating installation and maintenance jobs
51

52. Silviculture Note
Arborplanning: Species appropriate for a particular location, spp. For planting site,
assess spp. Diversity/canopy distribution, determines the future needs of urban forests
Arborsociology: Trees as a means of improving quality of life. The psychological value
of urban trees to be included in ‘ individual social benefits’ and it includes psychology
Pruning: Selective removal of plant parts for a purpose. Pruning can enhance plant
appearance and safeguard plant health and well being
Pruning is carried out for four major reasons: health, safety, appearance and production
Health: Removal of dead, diseased, injured and crowded branches
Safety: Pruning for street trees, and dead or dangerous wood that could fall causing injury
Appearance: Pruning can prevent obstruction of views and traffic
Production: To increase flower and fruits
Stress: Biological stress is any change in environmental conditions that might reduce or
adversely change the plants’ growth and development
Plant environmental (abiotic) stress constitutes a major limitation to urban forestry. The
major plant stresses are: drought, cold, heat, salinity, soil mineral deficiency, soil
mineral toxicity
Besides these, acid rain, gaseous and particulate pollution, security lighting, and toxic
wastes also cause stress
Stress encountered by plants:
Compacted soil Insufficient nutrition
Air pollution Little or excessive water supply
Infestation by pests and pathogens
Extension of day length by night lighting
Light intensity variation from deep shade to full sun
Reflection and re radiation that increases air temperature
Accidents, vandalism, neglect
Hails, frost
Stress can be avoided/minimized by choosing a favourable site, preparing site for
planting, selecting plant that are tolerant to site and relatively pest resistant and caring for
plants to ensure vigorous growth
Urban plant species
Eucalyptus spp Azadirachta indica
Jacaranda mimosifolia Melia azedirach
Albizzia procera Grevelia robusta
Polyalthia longifolia Prunus cerasoides
Callistemon viminalis Cryptomeria japonica
Nectanthes arbortristris Delonix regia
Albizzia lebek Cupressus torulosa
Cassia siamea
References
www.urbanforestry.info www.treecanada.ca
www.urbanforestry.com
www.fs.fed.us/ucf
Management Challenges
 Maintaining a tree and planting site inventory
 Quantifying and maximizing benefits of trees
 Minimizing costs
 Obtaining and maintaining public support and funding
52

53. Silviculture Note
 Establishing laws and practices for trees on public and private lands
Improvement felling(TSI):
It is not a silvicultural system as it neither aims at regenerating the crop, nor producing a crop
of distinctive characteristics. It is defined as the removal of inferior growing stock in the
interest of better growth of more valuable individuals. It is usually applied to mixed uneven-
aged forest. The following operations are usually done in improvement felling.
1. Felling of dead, dying, deformed , and diseased (4Ds) trees.
2. Felling of saleable unsound over mature trees which are not likely to survive up to the next
felling, provided these are not required for protection.
3. Felling of unsaleable over mature trees, if their removal benefits the other trees or
regeneration.
4. Feelings of unsound or badly shaped mature or immature trees, if it benefit other trees.
But it should not be a revenue filling.
5. Thinning of congested groups of trees and poles likely to benefit from the operation.
6. Removal of badly shaped and damaged saplings and advance growth expected to give
better coppice shoot
7. Removal of undesirable undergrowth or trees of inferior species. Which are preventing or
likely to prevent development of regeneration of the desired species.
8. Climber cutting
Conversions
Conversion is defined as a change from one silvicultural system or one (set of) species to
another. Thus the concept of conversion involves a change in crop composition and/or
silvicultural system by which the crop are regenerated and replaced by the new crops of
distinctive form.
Change in crop composition: It is often necessitated from any of the following reasons.
1. Increasing yield from forest: Pine plantation in hills, Eucalyptus plantation in Sagarnath ,
Sissoo plantation in Kohalpur and in other areas in degraded Sal forest enrichment planting
2. To meet the demand of industry: Populus, Eucalyptus, Acacia, Bombax, Teak
B. Change in the Silvicultural System:
Change from one silvicultural system to other is mainly for changing the character of the crop
and/or for changing the method of obtaining regeneration. Changes in silvicultural system is
due to following:
1. Advantage of a Particular System:
i. Selection or selection cum improvement felling replaced by Uniform System.
ii C.W.S. or Selection System replaced by C.W.R.
2. Failure of an Existing System:
53

54. Silviculture Note
i Uniform System to Sal in Haldwani failed and Indian irregular shelterwood system
was adopted.
ii Uniform System to Deodar in Chakrata failed and Indian irregular shelterwood system was
adopted.
iii In case of Fir and Spruce uniform system was changed to Selection System or Clear felling
with reservation followed by artificial regeneration.
iv In case of Teak uniform system was changed to Clear felling followed by natural or
artificial regeneration.
3. Advances in Silvicultural knowledge and perfection of regeneration techniques:
i. Conversion to Uniform:
By clear-felling followed by natural regeneration by seedling coppice as in Saranda
(Bihar), South Raipur (M.P) for Sal, North Betul(M.P)for Teak
Taungia for Sal and Teak, in parts of UP, West Bengal, MP, Maharastra and Kerala.
ii. Indian Irregular Shelterwood System is usually applied in case of evergreens in
Andaman and Arunachal Pardesh.
4. Development of communication and increase in market demand:
Selective felling or selection cum improvement changed to concentrated regeneration.
Techniques of Conversion:
When a change in silvicultural system is desired the entire area is not subjected to conversion
at a time. Only a part of the forest is taken up under new system and rest is worked under old
system where new areas are taken for conversion after completing conversion in the areas
taken previously.
Pace or speed of conversion:
The conversion period means the period in which conversion is to be done. The conversion
period is very important consideration. When the conversion period is short the conversion
proceeds with a fast speed on the other hand if conversion period is long, the conversion is
slow.
The following considerations affect the decision about the length of conversion period:
1. Sacrifice of immature crop (sacrifice is greater when conversion period short )
2. Proportion of the over mature growing stock with negative increment.
Larger the proportion of over mature trees the conversion period should be short.
Lesser ,, ,, ,, ,, ,, long.
3. Hiatus between the age of first converted crop and the exploitable age at the end of
conversion period:
The decision on the length of conversion period should also take into account the age of first
converted crop at the end of conversion period and compare it with exploitable age.
If the age of first converted crop is less than the exploitable age there will be a hiatus at the
end of conversion felling till the start of felling under the new system (uniform system).
Thus, the shorter the conversion period, the greater the hiatus. To over come this difficulty
following two alternatives can be adopted.
54

55. Silviculture Note
1.The conversion period should be so fixed, that the first converted crop is mature at the end
of conversion period.
2. Part of the young immature crop should be retained as part of the future crop. These
increases the mean age of converted crop and makes it fit for exploitation earlier.
Examples of Conversion:
Conversion to uniform by clear felling with natural regeneration and clear felling with
artificial regeneration.
Approx. Area = Area of Working circle x Working Plan Period
Conversion Period
PB1 allotted.
PBII unallotted.
PBIII converted or last PB.
1.Conversion to relatively less irregular crop by retaining young poles up to 20-30 cm.
Diameter in clear felling.
2. Conversion from CWS to CWR (Dry deciduous forest of MP, 1935 larger scale). The area
of working circle divided into three categories.
3. Conversion of coppice and CWS to high forest.
A.Conversion by natural regeneration (to retain the existing BL species)
i.Conversion of CWS to uniform broad-leaved high forest(by uniform).
ii.,, ,, ,, irregular ,, ,, ,,(by selection)
iii.,, ,, ,, coniferous high forest (in case of fir).
B.Conversion by artificial regeneration (To change sp. from BL- conifer)
i. Artificial conversion by clear felling.
ii. Artificial conversion under a shelterwood (fir).
iii. Artificial conversion by groups(spruce).
Unit 3. Tree improvement
Selection
In any plant or animal breeding program, there are a series of activities which will
ultimately determine the amount of genetic improvement. One of the most important activities
is choosing those individuals which will serve as parents for the next generation. The process
is known as selection and may be formally defined as “The non-random differential
reproduction of genotypes” or alternatively, “The actual procedure by which discrimination
between individuals with respect to their reproductive rate is arrived at” (Lerner). The end
result is that selection dictates that only certain individuals are allowed to transmit genetic
material to the next generation.
In improvement programmes, selection is more accurately referred to as artificial
selection. By contrast, organism whose reproductive success is not determined by human
choice, are considered to be subject of natural selection (Strickberger, 1968). For purpose of
convenience, the choosing of the parents by breeder in an improvement program is usually
called only “selection”, with the understanding that deliberate choices are to be made.
55

56. Silviculture Note
The use of selection in forest tree crops is certainly not a new or unique idea.
Archeological evidence suggests that plant improvement by selection has been practiced as
early as 2500 B.C. Early man simply utilized those individuals which best suited his needs to
reproduce the next generation (Blair, 1975). Allard (1960) discussed several crop
improvement efforts of the eighteenth century and noted the first reported accounts regarding
the effectiveness of selection in England, Belgium and America. Wright (1976) indicated that
first experiments in forest trees which provided a basis for selection were provenance
(Geographic Origin) tests begun about 1820. Since these early efforts, the uses of
sophisticated selection procedures have become common in both general plant breeding and
forest tree improvement.
Selection is usually the first step in any improvement program and determines how
much genetic gain can be obtained, as it provides the basis for the first and through a recurrent
system, succeeding generations the gain can be no greater than the quality of the parents used.
The importance of selection for the forest trees is certainly no less than for other crops. In fact,
several biological characteristics increase the importance of selection in forest trees above that
of annual or biennial crop species. First, trees live much longer than many other plants. Thus
trees are exposed to a wide variety of environmental conditions (insects, disease, weather, etc)
during their life time. Selected individuals must produce offspring which are adapted to the
various conditions which may be encountered. Trees also have a relatively long generation
interval (defined as the time from seed collection until an individual is selected and produce
seed) of several years; where as many crops have a one-year generation interval. Once chosen
an individual remains in the breeding population for a considerable length of time. The
longevity and extended generation interval are but two factors which necessitate the efficient
selection of individuals early in a tree breeding program in order to maximize genetic gain.
Variation:
Population variation: For selection to be a mechanism of change there must exist in the
population a certain amount of observed genetic differences or variation among individuals to
be selected. Conversely, selection, whether natural or artificial, doesn’t create additional
genetic variation, but acts only on variation which is already present (Allard, 1960). To a tree
breeder, the most important source of genetic variability is natural populations, and it is this
natural variation which serves as the raw material for genetic gain.
Natural variation can be considered to exist on several levels in a hierarchical arrangement.
The broadest and highest level in this arrangement is associated with differences among
species. The next level consists of geographic or provenance variation, where within species
differences are the result of adaptation to different environmental conditions at different
geographic locations. Within provenances, variation can also be identified as being among
sites, among stands within sites, within stands (trees to tree) and even within trees for some
characteristics (e.g. wood density, branching habit, etc.). An efficient selection program is
based on an evaluation of the amount and type of variation at each level, and then selecting
the best individuals based on that evaluation.
After the summarize the results of studies involving genetic variation in the forest
trees, note the provenance variation and tree to tree differences within the species. These two
components may account for as much as 90% of the within species variation, leading to the
fastest and cheapest gain in most tree improvement programs being obtained by selection from
the best seed source within the appropriate species. Additional gains are then made by
selecting the best individuals.
Components of Variation:
56

57. Silviculture Note
The parameters of mean and variance are used to describe a population, but it do not
indicate modes of inheritance or the population of the variation which is genetic of origin.
Only through partitioning the total variation into its components can those values be obtained.
The measurable or observable characteristics of an individual describe its phenotype.
An individual’s phenotype is determined by both. Its heredity and environment and can be
expressed by following equation:
P = G + E
Where,
P is the phenotype,
G is the genotype or the genetic material and
E is the environment to which the genotype is exposed.
In a manner analogous to the partitioning of an individuals’ phenotype, the total
phenotypic variation of a population can also be partitioned into genetic and environmental
variances
σP
2
= σG
2
+ σE
2
Where,
σP
2
= Phenotypic variation
σG
2
= Genotypic variation
σE
2
= Environmental variation
While the above formula is conceptually correct, the genetic variance must be further
partitioned into its component parts if the gains due to selection are to be accurately estimated.
The first attempt to partition the genotypic variance was made by Fisher (1918); and then
Fisher recognized three components of hereditary variance
1. An additive portion describing the difference between homozygotes at any single
locus,
2. A dominance component arising from interactions of alleles at a locus, and
3. An epistatic part associated with the interactions of non alleles.
The additive variation is that part of the genetic variation which can be passed in
from generation to generation. Additive genetic variation implies that the progeny of a cross is
intermediate in value between the parents (i.e. it is the average of the parents) when
environmental effects are absent. The importance of additive variance is that it makes
selection predictable and Felconer et. al. (1989) further defined additive variation as the
variance in breeding values and the chief cause of resemblance among relatives and therefore
the chief determinant of the response of population to selection.
Fisher’s 2nd
component, dominance, indicates that a given allele will essentially mask
the allele with which it is paired and the second allele will have no apparent effect.
The third component epistasis is due to interaction among loci. Both dominance and
epistasis are unique to specific gene combinations and generally do not contribute to genetic
gain from selection. In most cases, dominance and epistatic effects are grouped together and
collectively called non-additive genetic variations. Non-additive genetic variation can be
utilized in vegetative propagation systems where genotypes can be replicated.
An additional component which may contribute to the overall phenotypic variation is
the genotype by environmental interaction, which means that related individuals do not
respond at the same level or with the same ranking across various environments.
Genetic Gains:
57

58. SD
X1
X2
Fig: 1 Illustration of the difference between the average of the population
(x1) and the average of the selected tree (x2), which is the selection
differential (SD). Shaded area represents all tree selected.
Silviculture Note
Proper selection procedures have been applied and the best individuals chosen, what
amount of gain can be expected? In order to accurately estimate that value, two quantities are
necessary. These are the selection differential and heritability for the trait(s) under
consideration. The following discussions indicate the meaning of these values and how they
are used in estimating genetic gain.
a. Selection differential:
The difference in mean phenotype between the selected parents and the whole parental
population is called the selection differential. For example, assume that fig. 1 was
obtained from measurements of tree heights in a stand where selections are to be made.
The distribution is the familiar bell shaped curve with a large number of
measurements near the centre of the distribution (the population mean), with
decreasing number of such measurements either above or below the mean. Parents of
the next generations would be chosen only from the upper end of the distribution.
Assuming that the average height of trees in the stand (x1) equal to 90 feet, and the
average height of selected trees (x2) is 100 feet, the difference between these two
measurements 100-90 = 10 feet. This difference is known as the selection differential
(SD).
b. Heritability:
The second characteristics required for prediction of genetic gain is heritability.
Simply stated, heritability describes what portion of the parental superiority is
inherited. Expressing the same thing another way, heritability is the genetic portion of
the differences among trees, with the remaining portion caused by environment.
Heritability values, by definition, range from zero if all of the variation is due to the
environment; to one if the offspring’s performance exactly equals that of the average
of the parents.
Heritability may be further defined in one or two ways depending on the type
of genetic variance utilized for improvement. They are:
a. Narrow sense heritability is defined as the ratio of additive genetic variation to
total phenotypic variance or the proportion of the total variance that is attributable
to the additive effects of genes. In forest trees, selected individuals are selected for
58

59. Silviculture Note
their ability to produce improved offspring when mated with several other
individuals. Narrow sense heritability in forest trees are generally less than 0.5.
b. Broad sense heritability or the degree of genetic determination is defined as the
ration of total genetic variation (sum of additive and non-additive) to the total
phenotypic variation. The broad-sense heritability is the appropriate value to use in
calculating gain when non-additive variance can be utilized, such as through
vegetative reproduction or cross among specific parents.
Methods of Selection:
Several methods are available to select the parents for next generation. The choice of
which of these should be applied is dependent on the type and amount of information
available.
In initial stage where the value of parents is unknown, trees are often selected on the
basis of phenotypes.
Mass Selection: the selected individuals are grouped or massed together for mating. For this
reason individual tree selection is also called mass selection; although in some cases, it is also
known as individual selection. This method is most useful when there is a close indication of
the genotype by the phenotype, thus when the heritability or the amount of additive variation
is high.
Family Selection: It uses family performance to either accept or reject entire family. Within
family selection is based on the performance of an individual relative to its family means.
Progeny Testing: It is a method of selection which involves selection of parents trees based
upon the performance of their offspring.
Multiple Trait Selection: Several traits to be evaluated and selected in order to maximize
productivity or economic value. Example of traits often chosen for selection of forest trees
are-
- Superior height growth.
- Superior diameter growth.
- Good pruning ability.
- Straight, no crook or spiral bole.
- Horizontal branch angle.
- Small branches, no forking.
- Narrow, compact, well formed crown.
- Disease resistance.
- Insect resistance.
- Drought resistance.
- Wood characteristics (density, percent of summer wood).
- Environmental stress and no epicormic sprouting (hardwood only)
Individual Tree Selection:
- Finding superior tree.
- Grading the tree.
- Evaluating candidate tree.
- Market aided selection.
59