The document describes several types of shelterwood systems used for regenerating even-aged and uneven-aged forests, including the uniform system, group system, strip systems, tropical shelterwood system, and wedge system. The uniform system divides the forest into periodic blocks based on the age of the crop and involves seeding, secondary, and final fellings to gradually open the canopy and allow regeneration under shelter. The group system creates small gaps in the stand to shelter new regeneration growing in openings, concentrating the regeneration period.

1. Shelterwood System
Modification
Group 2
Student ID: 170528

2. Types of Shelterwood System/modified
Shelterwood Systems:
 The Uniform System
 The Group System
 The Strip Systems
 The Tropical Shelter-
wood System(modified
uniform system)
 The Wedge System
(modified strip system)
 The Irregular Shelterwood
System
for even-aged forest
for uneven-aged forest

3. The Uniform System
 “Shelterwood Uniform System”
 “Shelterwood Compartment System”
 Uniform opening of the canopy for the regeneration
purpose.
 Uniform regeneration under the shelter of remaining old
crop.
 Begins with a young even-aged forest until it reaches
maturity.
 Periodic thinning
-remove poorer stems
-favour the better trees.

4. Regeneration Felling
 3 types of felling:
i. The seeding felling
ii. The secondary felling
iii. The final felling
 3 stages of crop trees:
i. Seeding stage- seeding felling has been done
ii. Secondary stage- secondary felling have already
begun
iii. Final stage- awaits the final felling
The Uniform System

6. The seeding felling
 Opens the canopy to provide sufficient light to ensure survival for a
short time.
 Objective is not to stimulate seed production
 To allow long-wave radiation to warm the soil
 Admit sufficient light to enable young seedlings
The secondary felling
 Remove the overwood and uncover the young trees
 Provide more light, water, and nutrients
 Young crops fully established
 Sensitive shade-bearer: two/more secondary felling to give protection.
The final felling
 Made when young crop is well established
 Fully established young trees remains
 All remaining seed-bearers are removed
 Hardy light-demander: whole overwood may be removed
The Uniform System

7. Periodic Blocks
 According to the length of the regeneration period, the forest
may be divided on the basis of the age classes. These are
known as periodic blocks.
 A part or parts of forest set aside to be regenerated or
otherwise treated during a specified period.
The Uniform System
S.
No.
PBs Age of
crop
Activity
1. PBI 90-120 Felling/Regeneration
2. PBII 60-90 Thinning+Preperatory Felling
3. PBIII 30-60 Thinning
4. PBIV 0-30 Regeneration/seedling/cleaning/also final
felling if require in regeneration

8. The seed tree method
 Form of the uniform shelterwood system
 Seed bearers are widely spaced over the area to be
regenerated.
 Mainly used for light-demanding species with seed that is
dispersed by wind.
 Success of seed tree method depends on:
-careful choice of seed bearers
-high production of viable seed per tree
-adequate dispersal of seed on to well-prepared seed-beds
-good survival of seedlings during the critical early stages of
growth.
The Uniform System

9. The uniform system
Fig: The seed tree method in uniform shelterwood system

10. The Group System
 Small gaps are created in the stand.
 Adjacent trees can shelter the new regeneration
growing in the gaps.
 For example, these openings may comprise 20-40% of
the stand area during a given entry.
 Further cuts expand existing openings or create new
openings.
 The regeneration period for the cutting unit is still
concentrated at the beginning of the rotation over 20-30
years, creating an even-aged stand.

12. References:
1.Mathews, J. D. 1989. Silvicultural system.
Clarendon press, Oxford, U.K.
2.http://www.nipissingforest.com/shelterwood.ht
m
3.https://www.slideshare.net/sahl_2fast/shelterw
ood-system-kishor-aryal
4.https://www.slideshare.net/sahl_2fast/shelterw
ood-system-jyoti-ghimire