Silviculture system FOR201

UTD
Session – 2019
Presentation topic on : SILVICULTURAL SYSTEMS

Silvicultural system is define as the set of silviculture procedure worked out in
accordance with accepted set of silviculture principal by which crop constituting forest
are tended , harvested and replaced by new crops of distinctive from . It act as a tool for
achieving the objectives of forest management.

Silvicultural system may be defined as a
method of silvicultural procedure worked out
in accordance with accepted sets of
silvicultural principles by which, crops
constituting mature forests are harvested,
regenerated, tended and replaced by new
crops of distinctive forms. It begins with
regeneration felling and includes adoption of
some suitable method of regeneration and
tending of the new crop throughout of its life.
Fig. : Sequence of Silvicultural System

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. , silvicultural systems
are of following two types:
A. High forest systems and
B. Coppice systems

High forest systems are 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. The high
forest 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.

Classification of High Forests
Systems of Concentrated
Regeneration
Systems of Diffused
Regeneration
Accessory Systems
1. Two storied High Forest
2. High forest with Reserve
3. Improvement Felling System
Clear felling systems Shelter wood systems Seed tree System Selection System
1. Clear strip
2. Alternate strip
3. Patch clear
cut
1. Uniform system
2. Group system
3. Strip system
4. Irregular system
5. Indian Irregular
system
1. Uniform seed tree
2. Group seed tree
1.SingleTreeSelection
2.GroupSelection
Schematic Classification of Silvicultural System

Classification of Coppice System
That silvicultural system in which the crop originates
mainly from coppice and the rotation is short is called
coppice system.
Kinds of Coppice System (Low Forest System)
Simple Coppice System.
Coppice of Two Rotation System.
Shelter wood Coppice System.
Coppice with Standard System.
Coppice with Reserve System.
Coppice Selection System.
The Pollard System

I)Clear felling system
The clear felling system is 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 new crop produced is absolutely even-aged. It
requires large sums of money and large number of laborers to regenerate the forest
artificially.
Are those silvicultural system in which the regeneration felling are concentrated on a one part o

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.
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:
(I) Departmental plantation
(ii) Taungya
•Departmental Taungya
•Leased Taungya
•Village Taungya
Method of Natural Regeneration:
Natural regeneration from seed
Seeds stored in the area
Seeds received from outside
Natural regeneration from advanced growth

Advantages
It is simplest of all high forest system. It does not require a high degree of skill.
As felling is concentrated, the yield per unit area is more
 consequently the cost of felling and extraction is low.
Disadvantages
It is the most artificial system.
Soil remain open there is more danger of soil deterioration and erosion
The danger of weeds and grass invasion increases.
When the crop is pure it becomes more susceptible to damage by Insects,
plant parasites and pathogens.

Fig -Pattern of felling in alternate strip Fig-Pattern of felling in progressive strip

3. Block or patch clear cut system :
Fig - Patch clear cut system

b) Shelter wood system
A silvicultural system in which the over wood is removed gradually in two or
more successive fillings depending on the progress of regeneration. The primary
intent of this system is to protect and shelter the developing regeneration.
The trees which are growing vigorously are retained to provide shelter, Seed,
rapid diameter increment and value increment and protection of site against
deterioration.
Criteria for leave-trees in shelter wood systems are: larger, dominant trees, wind
firm trees, desirable species and desirable physical characteristics .
Fig Shelter wood system
Fig -Shelter wood tree

Advantages
Marking and felling of trees of the over wood are simpler than selection system
Soil is not completely denuded so there is little risk of soil deterioration and erosion.
As the regeneration operations are carried out under the shelter of older crop.
As the regeneration is obtained from seeds obtained from best selected trees, the new crop is superior.
Suitable system for the regeneration of both light demander and shade bearer saps.
Disadvantages
As the over wood is removed in more than one operation, there is much damage to the young crop.
After seeding felling, invasion by weeds and regeneration may be affected.
weeding and cleaning have to be done for longer period and the natural regeneration becomes costly.

Pattern of Fellings
A. Preparatory Filling : A felling made under a high forest system, usually towards the end of the
rotation, 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.
B. Regeneration felling :
1. Seeding felling : Opening the canopy of a mature stand to provide conditions for securing
regeneration from the seed of trees retained for that purpose. It is the first stage of regeneration
felling.
2. Secondary felling : A secondary felling carried out between the seeding felling and the final
felling under a shelter wood system in order to gradually 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.

3. Final felling :The removal of the last seed or shelter trees after regeneration has
been affected under a shelter wood system. It is the final stage in regeneration
felling when the area is completely stocked with established regeneration
Fig - Patterns of felling in shelter wood system

Periodic Block:
It is necessary to divide the rotation period in to as many parts as the number by which the rotation is
divisible by the time taken to regenerate an area.
Example;
If the rotation is 120 years and it takes 30 years to regenerate the area naturally.
The rotation will be divided into periods. As each of this part is felled and regenerated in a particular period, it is
called a periodic Block.
120/30 = 4 periodic blocks
Age Class (Age of crop in years)
PB:1
Age: 1-30 year
PB: 2
Age: 31-60
PB:3
Age: 61-90
PB: 4
Age: 91-120

Kinds of Shelter wood Systems
1. Uniform shelter wood system(Uniform System)
The canopy is uniformly opened up over the whole area of a compartment to obtain uniform regeneration
under the shelter of remaining old crop.
2. Strip shelter wood system
Regeneration felling is 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.
Uniform Shelter wood system Strip shelter wood system

3. Group shelter wood system
A silviculture system in which
regeneration fillings, instead of being
done uniformly all over the
compartment, are carried out in
scattered groups in which the foci of
regeneration can be enlarged
centrifugally to merge with each other
ultimately. Advance growth is the
main source of regeneration. It was
tried in Deodar, and Sal forests in
India but it was not successful.
Smallest circle for Final filling
Medium circle for secondary “
Largest “ for seeding Felling.
Group shelter wood system

4. One cut shelter wood system: In this system, regeneration felling is done in one operation. It
is applied only when advance regeneration is well.
One cut shelter wood system

5. Indian Irregular Shelter wood System
Silvicultural System is which mature crop with recalcitrant regeneration having large
quantities of advance growth of various ages and sizes including immature poles and
trees up to 40 cm dbh , which are retained as part of the future crop to complete
regeneration work . The crop to be regenerated is opened up irregularly and the
resultant crop is uneven aged. This system is applied to Sal, Deodar, Fir, Spruce and
other evergreen forests in India.

6. Irregular shelter wood 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.
Irregular shelter wood system

Seed tree system
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 are 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. Seed Trees should have wind firm, seed producing ability
with dominant crown and age of producing abundant seeds. Fig. see above.
Seed tree systemSeed tree

Kinds of Seed Tree System
1. Uniform seed tree system
In uniform seed tree system, individual trees are more or less uniformly distributed
throughout the block.
2. Group seed tree system
In a group seed tree system, seed trees are left in the block in small patches. These
patches may be arranged in irregular groups or in strips.

Number and distribution of seed trees depend on following factors:
Amount of seed produced/tree
The no. of seed required
Seed Dissemination
Number of viable seed produced
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.

C) Selection system
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 ages are found mixed together over every part of the area.
Such a crop is referred to as selection forest or all-aged forest. Regeneration operation is carried out
throughout the life of crop.
Selection system harvest stand Ten year after harvest

Selection system
Advantages:
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.
By maintaining continuous leaf cover, the selection systems conserve soil and moisture to the fullest
extent possible.
The selection forest produced is most resistant to injuries by insect pests and adverse climate factors.
It prevents invasion of grass and weeds.
Disadvantages:
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 spps.
As mature trees to be removed are scattered, cost of logging and extraction is high.
Felling, logging and extraction causes damage to the young crop.
Seed is obtained from good as well as bad trees; there is genetic deterioration of future crop.
There is much damage to regeneration by grazing.

Selection system
Selection system may be of following two types:
1. Single tree selection system: Single tree selection removes individual trees of all
size classes more or less uniformly throughout the stand to maintain an uneven-
aged stand.
Single tree selection

Selection system
2. Group tree selection system
Group selection systems also promote uneven-aged stands with clumps of even-aged trees well distributed
throughout the cutting unit.
Group tree selection system

Accessory System
Accessory systems refer to those high forest systems which originate from even-aged
systems by modification of technique, resulting in an irregular or two storied high forest.
Kinds:
1. Two-storied High Forest System
2. High Forest with Reserves System
1.Two-storied High Forest System
A system which results in the formation of a two-storied forest having
two strata in the canopy, but each of different species. For instance, deodar in the top canopy
and Quercusin the lower storey, etc. sometimes, it is obtained by under-planting with the
following objects:
(I )For soil protection. (II ) For increasing the no. of valuable species
(III ) For propagation of species which can not be raised in the open

2. High Forest with Reserves System
An accessory silvicultural system in which selected trees of the crop being regenerated
are retained for part or whole of the second rotation in order to produce large sized
timbers .The recent trends of reserving some trees of the old crop in the clear-
felling system is an example of this system In uniform system some trees are
retained at the time of final felling for light increment.
Actually, improvement felling is not a silvicultural system as it neither aims at
regenerating crop, not producing a crop of distinctive characteristics. Large areas of
degraded and poor forests are likely to remain under improvement felling top repair
them for eventual management aiming at bringing the forests to the normal state. It is
only treated as an accessory system suggested by Trevor.

Improvement felling is defined as a method of treatment involving essentially the
removal of inferior growing stock in the interest of better growth of the more valuable
individuals. It is usually applied to mixed uneven-aged forests. The following
operations are usually done in this fillings:
( i) Dead, dying (>75% parts) and diseased trees
(ii)Saleable unsound over-mature trees
(iii)Unsound or badly shaped mature or immature trees
(iv)Thinning of congested groups of poles and trees
(v)Cutting back of badly –shaped and damaged saplings and advance growth
(vi)Removal of undesirable undergrowth or trees of inferior species
(vii)Climber cutting

Coppice System (Low Forest System)
The silvicultural system in which the crop is regenerated mainly from stool coppice and
with short rotation is known to be coppice system. Reproduction is obtained from the
shoots arising from the adventitious buds of the stump of felled trees. Coppice systems
are further classified on the basis of pattern of felling and mode of regeneration as well
1. Simple coppice system
A silvicultural system based on stool coppice in which the old crop is clear felled
completely with no reservation.
Simple coppice System

Season for coppicing:
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.
During the dormancy period. (from Nov. –Feb./March)
Method of felling:
The stump should neither be too low nor too high.
The lower the stump, the better it is for coppice shoot.
But if the trees are cut very low there is a danger of the stump splitting and or drying up from top.
On the other hand, the higher the stumps, the greater the possibility of shoots being damaged by wind
or animals.Stumps are usually kept, 15-25 cm high. (10 cm for eucalyptus)

2. Coppice with standard system
It is silvicultural system based on stool 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. It is usually applied in shade-tolerant species.
Purpose of standards: (i) To supply large size timber (ii) To protection against frost (iii) To enrichment of
coppice (iv) To provide seedling regeneration (v) To increase in revenue
Coppice with standard

Advantages:
There is greater protection to the soil.
Advantage of heavy shelter wood felling and selection system.
Standards serve as seed bearers and provide seed.
The investment is small and the net return is higher.
Aesthetically superior than simple coppice.
Disadvantages:
It requires great skill in maintaining correct balance between
standards and coppice and between standards of different age
classes.
This is a combination of simple coppice system and high forest
system with the advantage of none.It has an exhaustive effect on soil.
Felling and extraction cost is higher than high forest

3. Coppice with Reserve system
A silvicultural system in which felling is done only in suitable areas likely to benefit,
after reserving all financially immature growth of principal as well as other valuable
miscellaneous species, either singly or in optimally spaced groups, trees yielding
products of economic importance and protective reasons, first introduced in 1934-35.
Reservation by area

Pattern of felling:
In this system, the emphasis is not on felling but on conservation. Distinguish areas which, require protection or
some improvement felling and areas in which felling can be done according to the requirement of crop, local
people, and site..
Tending:
Tending should be done-clearing, climber cutting, and reduction of coppice shoots.
Character of the crop
The resultant crop under this system comprises of irregular groups of even aged coppice with uneven aged
reserve crop scattered irregularly. Thus, taking the crop as whole, it is uneven aged.
Advantages:
It helps in improving the quality of locality as a result of soil and moisture
conservation, maintenance of crop mixture.
It helps in improving the condition and composition of crop.
It fulfills the needs of local population and the requirement of industries.
Thus it offers best financial returns per unit area.
Disadvantages:
Its execution requires a high degree of skill.
Reservation of a large number of trees affects coppice growth adversely

Conditions of applicability:
When the crop varies greatly in density, composition, and quality and population of
valuable species is low .
When most of the species are good coppices and the coppicing power of most
valuable species is vigorous.
When valuable species in the crop is light demanders.
Coppice with reserves system is not suitable:
When valuable species are shade bears and frost tenders.
When there is likelihood of invasion of fast growing obnoxious weeds, shrubs, and
grasses such as Lantana, and Imperata.
When the crop does not contain valuable species and there is no hope to improving it
by coppicing.
When it is not possible to protect the area against fire and grazing at least for five
years after main felling.

4. Coppice of Two Rotations System
A coppice system based on stool coppice in which after the initial coppicing of the crop
at the beginning of the first rotation, part of the crop is not coppiced to produce large
sized timber. The number of trees so reserved from being coppiced again in the second
rotation, depends on the quantity of large sized timber required in the market.
5. Shelter wood Coppice System
A coppice system in which even in the initial coppicing, shelter wood (of almost 125 to
150 trees per ha) is retained for frost protection.
It is specially suited to frost tender species in frosty localities and forest hardy species,
promising are selected, which are removed gradually when the coppice shoots are fully
established and are free from frost danger. When coppice shoots are 5 years old, the
shelter trees are to be reduced to 63 to 75 and after 10 years , all the shelter trees are
removed. The resultant crop is even aged.

6. Coppice Selection System
A coppice system in which fillings are carried out on the principles of selection
system, but regeneration is obtained by coppice. The resultant crop is uneven
aged . can be suitably applied in Acacia species and also applied for the
management of small area of poor quality shorea forest.
7. The Pollard System
Pollard is defined as a tree whose stem are cut off in order to obtain a flush of
shoots, usually above the height to which the browsing animals can reach. This
system is suitable when demand of fuel wood and fodder is high. For example,
salix, Hardwickiabinata, etc species are suited for pollarding, which have
high coppicing power.

Considerations for Silviculture Systems
A good silvicultural system is a long-term program of treatment designed to fit a specific set
of circumstances (Smith, 1962).
A rational silvicultural system for a particular stand should fit logically into the overall
management plan for the forest of which the stand is a part and represent the best possible
amalgam of attempts to satisfy all the following major considerations:
1. Harmony with goals and characteristics of ownership
2. Provision for regeneration
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

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 crops are regenerated and
replaced by the new crops of distinctive form.
A) 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 , Sissoo plantation and in others in degraded Sal forest
enrichment planting.
2. To meet the demand of industries: Popular, Eucalyptus, Acacia,
Bamboo, Teak, etc.

Conclusion
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.

References:
1) Books : Indian forestry
by Manikandan & Prabhu (Author)
Paperback
Publisher: Jain Bros; 6th Edition,2016 edition (1 January 2013)
Language: English
ASIN: B00IG3401.
Other sources : Website : indian forest management hand book Pdf .

Silviculture system FOR201

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