An Introduction to Silvicultural Systems Practiced in Pakistan.

  DEFINITION

Ø  The process by which the crops constituting a forest are tended, removed and replaced by new crops, resulting in the production of woods of a distinctive form.


SILVICULTURE

Ø  “It is the art and science of controlling the establishment, growth, composition and, quality of forest vegetation for the full range of forests resource objectives”
Ø  Silviculture is also used to manage forests for Wildlife, Water, Recreation, Aesthetic or any combination of these or other forest uses.
Ø  “Silviculture also ensure the long-term continuity of essential ecological functions and the health and productivity of forested ecosystem”(RALPH NYLAND_1996).
Ø  “Silvicultural practice consists of the various treatments to that may be applied to forest stands to maintain and enhance their utility for any purpose” (DAVID M.SMITH_1986).
Ø  “Silviculture is that branch of forestry which deals with the establishment, development, care and, Reproduction of stands of timber.” (TOUMEY AND KARSTIEN).
Ø   “The term Silviculture in English Commonly refers to only certain aspects of the theory and practice of raising Forest Crops.” (CHAMPION AND SETH)
Ø  Indian Forest and Forest Products Terminology Tells that: “Silviculture is the art and science of Cultivating Forest crops.”

SILVICULTURAL SYSTEM

Ø  “A Silvicultural system is a planned program of treatments during the whole life of a stand designed to achieve specific stand structure objectives. This programme of treatments integrate specific harvesting, Regeneration and stand to tend methods to achieve a predictable yield of benefits from the stand over time”
Ø  The general aim of silviculture is to ensure that most available growing space is filled with “Useful Plant”.
Ø  Silviculturists generally deal with far less than perfect stands. Imperfect stands can be improved, but not to ideal conditions even with the best of knowledge.
Ø  With erroneous knowledge it is quite easy to ruin the ability of a stand to meet the Landowners objectives.
Ø  It is defined as the process by which the crops constituting a forest are tended, removed and replaced by new crops resulting in the production of woods of a distinctive form.
Ø  The system implies:-
i.    Method of regeneration of individual crops.
ii.   Form crop product.
iii. Spatial distribution and arrangement of crops over the area.

 ESSENCE OF SILVICULTURAL SYSTEM

Ø  The essence of Silviculture system is:-
i)      The methods adopted for the regeneration of the crop.
ii)    The character of the crops produced by such system.
iii)   The distribution of the age-class over the area of the forest.
Ø  There are three important operations that are Regeneration, Tending and Removal of mature trees, which decide the Silvicultural system.
Ø  The Silvicultural system can be conveniently classified according to the method of carrying out the felling which removes the mature crop with a view to Regeneration, and the type of crop produced by the method of Regeneration employed.
Ø  Each system produces a crop of distinctive form in the young stages, though after some years have elapsed it is usually possible to treat the crop as either Even-aged (UNIFORM) or Uneven-aged (IRREGULAR) for purpose of management.
Ø  The methods adopted for the regeneration of the crop. The characters of the crops produced by such system and distribution of the age-classes over the area of the forest.


SILVICULTURAL SYSTEM

Ø  To cut the trees from a forest to fell the trees carefully, removing the felled timber from the forest and planting new species at the places of the felled trees, this whole procedure is called silvicultural system.
Ø  In other words, cutting the woods from the forest and placing a new species in the places of the felled log is included in silvicultural operations.
Ø  Mainly there are three silvicultural systems
1. High forest system
2. Coppice system
3. Accessory system
Ø  High forest system includes those silvicultural operations which originate from seeds.
Ø  The coppice system consists of the stool shoots coming out from the remaining parts of the stem of a felled tree.

OBJECTIVES OF SILVICULTURAL SYSTEM

Ø  A Silvicultural system generally has the following basic goals /objectives.
1.     Meets the goal and objectives of the Landowner.
2.     Produces predicable harvest over the long-term.
3.     Provision for regeneration /reproduction.
4.     Balance biological/ecological and economic concerns to ensure renewability of resources.
5.     Efficient use of growing space and site quality.
6.     Provision of sustain yield.
7.     Consider forest health issues/control of damaging agencies.
8.     Production of species of Economic value.
9.     An increase in volume per unit area.
10.  Production of good quality Timber.
11.  Reduction in Age of Rotation.
12.  Raising Forests in hitherto blank areas.
13.  Introducing suitable exotics.
14.  Creating a man-made forest for enhancing green cover.

PROPERTIES OF SILVICULTURAL SYSTEM

  1. Each system must cover the whole life of the crop.
  2. A system must furthermore ensure the soil fertility and improvement.
  3. Risks of damage from adverse factors such as winds, insects, fungi, snow, and desiccation are kept low.
  4. Tending of immature stock must continue providing good conditions for growth.
  5. Mature trees must be removed .in such a way that regeneration can be established by naturally or artificially.
  6. Felling should be so planned to ensure sustained annual or periodic yield of the type can be achieved.



CLASSIFICATION OF SILVICULTURAL SYSTEM:-

Ø  Classification according to the method of carrying out the fellings which remove the mature crop with a view to obtain regeneration and the type of crop produced by the method of regeneration employed.
Ø  Each system produces a crop of distinctive form in the young age though after some years lapsed it is usually possible to treat the crop as either eve-aged (uniform) or uneven-aged (irregular).
1.     High forest systems
2.     Coppice system

1.     HIGH FOREST SYSTEM:-

§  Crops normally of seedling origin
(a)   The system of concentrated regeneration
(i)              Clear felling systems
(ii)            Shelterwood systems
(b)   Selection systems
(c)   Accessory systems

(i)              CLEAR FELLING SYSTEMS:-

Ø  Where the mature crop is removed in one operation
(a)   The clear felling system
(b)   The clear strip system
(c)   The alternate strip system

(ii)            SHELTERWOOD SYSTEM:-

Ø  Where the mature crop is removed in a series of operations, the first of which is the seeding felling and the last is the final felling, other fellings if any are called secondary fellings.
Ø  The interval between the seeding felling and the final felling on a particular area, such as a compartment, is the regeneration interval and determines the degree of uniformity of the resulting crop.
a.      The uniform system
b.     The group system
c.      The Shelterwood strip system
d.     Irregular shelterwood system

SELECTION SYSTEMS:-

Ø  Where regeneration fellings are distributed over the whole felling series (except in so far as a felling cycle introduces a modification) and the crop is always irregular.
i.       The selection system
ii.     The group selection system

ACCESSORY SYSTEMS:-

Ø  Resulting in irregular or two storied high forest
a.      Two storied high forest system
b.     High forest with reserve system
c.      Improvement felling

COPPICE SYSTEMS:-

Ø  Where the crop originates mainly from coppice and where the rotation of the coppice is short.
i.                 The simple coppice system
ii.               The shelterwood coppice system
iii.             The coppice with standards system
iv.             The selection coppice system
v.               The pollard system

HIGH FOREST SYSTEM:-

Where the regeneration is normally of seedling origin, either natural or artificial (or combination of both) and when the rotation is generally long.

SYSTEM OF CONCENTRATED REGENERATION:-

Where the regeneration felling are for the time being concentrated on part of the felling series.

1. CLEAR CUTTING SYSTEM:-

Felling and regeneration for a time being concentrated on part of the forest area only
Old crop cleared by one single felling, resulting crop is Even-aged.

2. UNIFORM SYSTEM:-

Regeneration fellings distributed over whole compartment or sub-compartment
i.                 An opening of canopy even, young crop less even-aged and uniform is called a uniform system.
ii.               An opening of the canopy by scattered gaps, young crop more or less even aged is called Group System.
iii.             An opening of canopy irregular and gradual, young crop somewhat uneven age is called irregular shelterwood system.

3.   STRIP SYSTEM:-

Regeneration felling confined to a certain portion of compartment or sub-compartment at a time,
i.                 Felling in the strip is called strip system
ii.               Felling beginning in internal lines and advancing outwards in wedge formation is called a wedge system.

METHODS OF REGENERATION

            Regeneration may be affected in 3 ways:-
1.     Natural regeneration from seed.
2.     Natural regeneration from coppice.
3.     Artificial regeneration from sowing and planting.

 

VARIOUS SYSTEMS (MAJORS SYSTEMS)

I.    Clear felling system
II.   Shelter wood system
III. Selection system
IV. Coppice system
V.  Accessory system
(Each of the above stated Silviculture Systems will be discussed in separate posts).
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