Choice of Silviculture System

CHOICE OF SILVICULTURE SYSTEM

·            Each Silvicultural system has its own specific advantages and disadvantages which affect the kind of produce yielded, resistance to external dangers and the preservation of the local conditions of soil and climate.
·                 The principal conditions affecting the question are
1.               The suitability of the system to the principal species.
2.               The preservation and improvement of the local conditions of soil and climate.
3.               The resistance offered to external danger.
4.               The safety and simplicity of the method of regeneration.
5.               The quantity and quality of the produce.
6.               The intensity of management.
7.               The existence or absence of forest rights.
8.               Aesthetic consideration.
9.               Environmental consideration
10.            Personnel factor and labor.
11.            Transportation facility
·                 Each silvicultural system has its own specific advantages and disadvantages. A careful study of the prevailing conditions in any given locality is a most before the choice of a system is finally settled. The factors to be taken into consideration fall into two broad groups.
1.     Protection
2.     Economic


PROTECTIVE FACTORS:-

1.     The safety and simplicity of the method of regeneration.
2.     The preservation and improvement of the local conditions of soil and climate i.e nature of terrain and soil.
3.     The resistance offered to external danger.
4.     Biodiversity and aesthetic value.
5.     The suitability of the system to the principal specie.

ECONOMIC FACTORS:-

  1. The quantity and quality of produce.
  2. The intensity of management.
  3. The existence or absence of rights.
  4. Personal and labor.
  5. Factors of transport.

COMMENTS:-

·       The suitability of the system to the principal specie is always the most important consideration e.g.
      Conifers are not fit for the coppice system.
·       High crowned light-demanding trees would be better raised as standards over a coppice or mixed with shade bearing species than treated under the high forest system in a pure crop.
·       The selection and irregular shelterwood system favor shade bearers as compare to the light demanding species.
·       The two storied high forest system provides for the raising of two species having different growth rates, together provided the species having slower growth rate as a shade bearer.
·       Strong light demanders are best suited to be worked under the clearfelling system, the clear strip system, or any short shelterwood system with very open seeding felling.
·       Clearfelling system should be avoided in areas which are subject to soil erosion, landslides, avalanches, in water catchment areas.
·       The irregular shelterwood system, two storied high forest system and selection system can be applied in areas which are liable to severe soil erosion.
E.g. A large number of the conifers forest of the western Himalayan is being worked under the Punjab irregular shelterwood system with minor modification.
·       In areas where snow damage occurs uneven-aged system like the selection or the irregular shelterwood system are adopted.
·       The uniform system suited to the furry of the wind storm.
·       In forest areas clearfelling and coppice system is avoided.
·       If there is a risk of fire occurrence, standards may have to be left.
·       As for as technical skill is concerned, the selection system is the most difficult to operate.
·       As far as the labor required per unit outturn is concerned the coppice with standards system needs the highest and the clearfelling system the least labor force.
·       For small timber for fuelwood, the coppice system is best suited.
·       When there is a demand for large sized timber, any high forest system may be adopted.
·       The coppice with the standard system is suited for measuring a mixed local demand for fuelwood, poles and a certain quality of large sizes.
·       The high forest system is able to meet the demand for clean, cylindrical timber of a good quality.
·       The produce obtained under the selection system is more tapering and branchy.
·       The two storied high forest with standards system is best suited for the production of clean, straight and large size timber.
·       For mining timber and pulpwood, the clearfelling system is best suited.
·       Keeping in view the cost of felling, conversion and extraction, the clearfelling system and coppice system are the best and the selection system, least suited.
·       Among the high forest system regeneration with the short period is beneficial than the longer period.
·       Early returns are available in case of coppice system.
·       Even aged system furnishes early return than uneven-aged.
·       Selection system is best suited for areas where there is a lack of roads for extraction.
·       Clearfelling system is placed to lowest on an aesthetic point of view.
·       It is advisable to adopt a short period system than the long period system in case of grazing rights.


CONVERSION SYSTEM:-

·       The conversion of forest from one silvicultural system to another is as follows.
                 i.          Form irregular high forest to coppice.
               ii.          From coppice to high forest.
             iii.          From irregular to a regular forest.

IRREGULAR HIGH FOREST TO COPPICE:-

·       The conversion of crop composed of trees of all ages intermingled, which has been either to be worked by the selection system method, into a state coppice, with or without standards, offer no difficulty, and on any usually be effected without much sacrifice of production.
·       The area is divided up into as many equal coupes as there are years in the coppice rotation to be adopted, the conversion felling will proceed successively through these coupes.
·       It is essential that the greater part of the crop to be converted should still be sufficiently young to be able to reproduce itself easily by stool shoots and it is only in those parts of the forest in which this condition obtain that coppice felling can be at once carried out.
·       The older parts of the forest in which the existing stock is composed of trees which have passed the age at which they can be relied upon to produce strong and abundant stool-shoots will have to be regenerated by seed before the conversion can be affected.
·       Seed fellings will, therefore, have to be made in the older parts of the area, if such exist, and the leaf cover opened and raised, then when the regeneration by seed has been affected, and a sufficient stock of young growth has been brought into existence , a coppice felling may be proceeded with
·       In any case, a certain number of the suitable stem may, if desirable, be selected from among the trees of the old crop which are too old to coppice and may be reserved as a standard. Such trees should be of course be trees of the principal species, suitably distributed, capable of giving seed freely of good type shape and well-developed crown and strong enough to support isolation.
·       There will be in addition be an almost unlimited number of young seedling trees of all ages from which to choose a suitable number as a standard. These may very profitably be prepared for their impending change of state by means of thinning, specially made with this object some years before the conversion felling.

FROM COPPICE TO HIGH FORESTS

·       It has been stated that stems of coppice origin will not grow on to maturity when the equal stem of seedling origin. This certainly holds true of coppice shoots growing on old and worn out stools. It does not apply to coppice shoots springing from ground level and originating from young stools. Such stem will be allowed to grow up into a high forest.
·       Conifers cannot be substituted for the coppice of the plains owing to the differences in a climate so that this conversion from broad-Leaved coppice to conifers does not arise.
·       Worthless Oak Forests in the Himalaya has, however, been converted to Deodar by opening out the canopy and underplanting but this procedure can hardly be defined as a System.

FROM IRREGULAR TO REGULAR HIGH FOREST:-

·       It is obviously necessary that the conversion period should be approximately equal to the future rotation.
·       The area must be organized into Periodic Blocks and one block must be brought under Regeneration in accordance with the prescription of a working plan.
·       Supposing a Conversion period is of 90 years and a period of 30 years, the area would be divided into three equi-productive blocks.
BLOCK I; would come under Regeneration
BLOCK II; would come under Regeneration after 30 years
BLOCK III; would come under Regeneration after 60 years
The class of fellings to be carried out in BLOCK II & III is more the concern of management than of silviculture.
Usually, while there is no objection to continuing selection felling in BLOCK III nothing should be removed from BLOCK II except Moribund trees which can survive for the next 30 years.
Nothing should be done to decrease the average maturity of the crop in BLOCK II, but on the other hand, by carrying out proper thinning every endeavor should be made to increase the average diameter of trees.
In arranging the general plan of operations and forming the different blocks, those compartments which contain the largest proportion of mature trees and trees approaching maturity will naturally be placed in BLOCK I for early conversion, and compartments containing young crops in the last period.
———-
For Correction and Improvements please use the comments section below. 


SEE ALSO:  Plantago ciliata subsp. Lanata

Leave a Reply

Your email address will not be published. Required fields are marked *