Forest disturbances, Forest ecology, Silviculture, Forest

1. A term paper on
A Review About Various Types Of Forest
Disturbances
(Term Paper on Advance Forest Ecology“SFB 702”)
Presenter
Anand Jha
Roll: 04
M.Sc. forestry,1st yr.1st semester
Institute of Forestry,
Hetauda Campus, Hetauda
Nepal 1
Submitted to
Yogendra Yadav
Module Co-ordinater, Advance
Forest Ecology
Assistant professor,
Institute of Forestry,
Hetauda Campus, Hetauda,
Nepal

2. Presentation Outline
• Introduction
• Objective of the study
• Methodology
• Discussions and results
• Recommendations
• References
2

3. Forest Disturbance
• Events that cause change in forest
structure and composition of
forest ecosystem.
Types of Forest Disturbances
• Natural
• Anthropogenic
3

4. Examples of Forest Disturbances
• Fire
• Flooding
• Wind
• Large mammals
• Insect damage and diseases
Disturbances can be described by :
• Frequency
• Distribution
• Return Interval
• Area covered
• Magnitude 4

5. Major disturbance (Stand-replacing disturbance):
Removal/Killing of all the existing trees above the
forest floor vegetation
Minor Disturbance: Leave pre-disturbance trees alive
Forest development after minor disturbance is
more complicated than after major disturbance.
5

6. Objective of the Study
6
• General Objective
• To review about various types of
disturbances present in the forest .

7. Methodology
7
• Secondary data collection
• Various published and unpublished
articles.
• Newspapers
• Webpage
• Etc…

8. Forest Disturbance
• A disturbance is defined as a temporary change in
average environmental conditions that cause a
pronounced change in an ecosystem. (DFRS, 2014)
• Nearly two-thirds of the total forest area in the
country was affected by grazing. Tree cutting, bush
cutting, lahra cutting, lopping and forest fire were
also common. Other anthropogenic disturbances, such
as bark removal from the base of a tree, snaring, foot
trails, forest roads, etc were observed in about one-
quarter of the surveyed forest areas .(DFRS, 2018)
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9. Characteristics of Different Disturbance Agents
Forest Fires:
9
•Fires often occur in years and seasons of low
humidity .
•A lack of snow on the ground
•Available fuel load

10. Damages due to Fire
• Damage the habitat of the environment—which
depends on the soil type and the fire’s intensity
• Affect the species population and distribution after
an incident
• Incur costly evacuations and destruction
• Create heavy smog that is harmful to living things
• Take animal and human lives
(chandler et al. 1983)
The coverage and number of native grass species were
higher in controlled fire plot than in manual cutting
and control plots. The study concludes that
controlled fire is better than manual cutting and
control treatments for the management of
grassland.(U Aryal et al. 2018)
10

11. Damage to forest by wild animals:
• The damage caused by wild animals varies with
animals and the size of the plants.
• While some animals cause only mechanical
damage, others browse on the foliage, destroy
the seeds or fruits, strip the bark or kill the plants
by gnawing at the collar or cutting the roots.
• The younger the plant, the greater are the
chances of its being damaged.
11

12. Plant diseases:
Plant diseases can be defined as the series of invisible and visible
responses of plants cells and tissues to a pathogenic organism or
environmental factor that result in adverse changes in the form,
function, or integrity of the plant and may lead to partial
impairment or death of the entire plant.
Due to disease at least six vital processes can be affected;
• Food storage in the form of seed, roots, stems and bud.
• Juvenile growth as either seedling or shoot development.
• Root extension in the procurement of water and included
minerals.
• Water transport.
• Food manufacture or photosynthesis.
• Translocation of photosynthetic to sites of cell utilization .12

13. Insects:
Insects are causing damage to seeds, nurseries, plantations,
natural forests and stored timber in various ways:
• Defoliation, skeletonisation, Phloem and wood boring, Seed
feeding, Sap-sucking, Shoot-boring, Root feeding, etc.
Birds
The major damages caused by birds are :
• Nursery seed feeding
• Damage to fruits and seeds.
13

14. Control Measures from Forest Fire
• Direct preventive measure (Clearing
camping sites and areas along paths and
roads, Early burnings, Burning of grassy
blanks etc)
• Indirect preventive measure(Goodwill of
the local people , education, legislative
measures, putting up notices prohibiting
kindling, keeping and carrying of fire in
forest areas in fire season)
• Remedial measure ( Detection, quick
communication about occurrence of fire,
quick action for suppression of fire,
arrangement of labour, arrangement for
tools, food, water, lighting etc, arrangement
for transport of men and material.
14

15. Control Measures against wild animals
• The only way to prevent damage by other animals is to
fence the area by appropriate fencing device. But it can
be done only in nursery or a small regeneration area.
Control Measures against Birds
The incidence of birds damage particularly in nurseries
can be reduced considerably by;
• Keeping nursery beds covered by wire netting.
• Putting up scare-crows.
• Firing up blank cartridge.
• Coating seeds with red-lead. 15

16. Control Measures against Diseases
• Disease detection , damage appraisal, , disease management
strategies, ,Integrated Forest protection, Development of a
pest/pathogen management system.
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Control Measures against Pests
Integrated pest management:
“Integrated Pest Management (IPM) means the careful consideration of
all available pest control techniques and subsequent integration of
appropriate measures that discourage the development of pest
populations and keep pesticides and other interventions to levels that
are economically justified and reduce or minimize risks to human and
animal health and the environment. IPM emphasizes the growth of a
healthy crop with the least possible disruption to agro-ecosystems and
encourages natural pest control mechanisms.” (FAO, 2007)

17. Conclusions
• Thus the major disturbances found in forest
are Fire, Pest attacks, Diseases, Wild
animals, Birds, etc .
• Not all disturbances are destructive or
negative to the overall forest ecosystem.
Many natural disturbances allow for
renewal and growth and often release
necessary nutrients.
17

18. Recommendations
• Various scientific tools and techniques
should be applied to decrease the
damage to forest due to various forest
disturbances .
• Anthropogenic forest disturbances that
is harmful should me minimized.
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19. References
• Aryal, Upendra & Wagle, Bishnu & Lamichhane, B & Parajuli, Ashok &
Thapa, Parbati. (2018). Effectiveness of control measures of Mikania
micrantha on grassland: a case study from grassland in Sauraha area of
Chitwan National Park. Banko Janakari. 27. 144.
10.3126/banko.v27i3.20559.
• Chandler, C., Cheney, P., Thomas, P., Trabaud, L., & Williams, D.
(1983). Fire in forestry. Volume 1. Forest fire behavior and effects. Volume 2. Forest
fire management and organization. John Wiley & Sons, Inc..
• DFRS, 2015. State of Nepal's Forests. Forest Resource Assessment
(FRA) Nepal, Department of Forest Research and Survey (DFRS).
Kathmandu, Nepal.
• Vreysen, M. J. B., Gerardo-Abaya, J., & Cayol, J. P. (2007). Lessons from
Area-Wide Integrated Pest Management (AW-IPM) Programmes with an
SIT Component: an FAO//IAEA Perspective. In Area-wide control of insect
pests (pp. 723-744). Springer, Dordrecht
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20. Any
Suggestions
Heartly
Welcome!!!