silvicultural system

Silvicultural System (Harvesting System)

FORESTER’S

By Javed Iqbal PhD Scholar Department of Silviculture, Faculty of Forestry and Wood Sc, Czech University of Life Sciences, Prague

Introduction FORESTER’S


Need of Silvicultural System •Systematic Management •Decisions for ideal aimed •Bring Forest to the normal condition

Definition FORESTER’S


•A set of Silvicultural Operations by which forest crops are tended, harvested, and replaced by new crops constitute a Silvicultural System. •Silvicultural Operation (Any Operation for the benefit of the forest crop) •Tended (Behave for the Crop value) •Harvested (Systematic cutting of Forest Crop) •Replaced (Afforestation, Refforestation, Regeneration

Characteristics of Slivicultural System

FORESTER’S


•Each system must cover Whole life •Produce stand of distinctive Form •Maintained Soil Fertility or improve Future Yield •Risks of damage from adverse factors (wind, insect, fungi, snow) •Mature tree must be removed •Adequate regeneration

Silvicultural System FORESTER’S


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Coppice System

High Forest System

Coppice With Standard

Two Storeyed High Forest System

System of Concentrated Regeneration

System of Dispersed Regeneration

Selection Coppice System

Simple Coppice System

Selection System

Group Selection System

Clear Felling System

Shelterwood System

Strip System Group System Uniform System

Irregular Shelterwood System

Classification FORESTER’S


•Method of regeneration

The Selection System FORESTER’S


SS of regenerating a forest stand, and maintaining an uneven-aged structure, by removing some trees in all size classes either singly, in small groups, or in steps. Types: Single tree selection system A method of creating new age classes in uneven-aged stands in which individual trees of all size classes are removed more-or-less uniformly throughout the stand to achieve desired stand structural characteristics. Group selection system A method of regenerating uneven-aged stands in which trees are removed, and new age classes are established, in small groups. The maximum width of groups is approximately twice the height of the mature trees, with small openings providing microenvironment suitable for tolerant regeneration and the larger openings providing conditions suitable for more intolerant regeneration. In the Group Selection System, the management unit or stand in which regeneration, growth, and yield are regulated consists of a landscape containing an aggregation of groups. Group Selection with Reserves A variant of the Group Selection Method in which some trees within the group are not cut to attain goals other than regeneration within the group. Overtopped: Trees of varying levels of vigor that have their crowns completely covered by the crowns of one or more neighboring trees.

Procedure: FORESTER’S


Individual trees or groups of mature, unhealthy or other selected trees are harvested periodically. Most of the trees are left to regenerate the stand naturally. Before any harvesting is done, an inventory of the forest is completed. The inventory identifies the tree species, the different sizes of trees, the quality and health of the trees and the availability of habitat in the forest. Based on this information, a tree marking prescription is written and all trees to be cut are marked with yellow paint. Crop trees are usually marked with blue paint. Crop trees are the trees you want to grow for their future commercial value, for their value to wildlife or as sources of seed for regenerating desired tree species. Every eight to 15 years, the stand is thinned to give crop trees room to grow, and some unhealthy and mature crop trees are harvested. Care is taken during the thinning and harvesting operations to avoid damaging the site and the crop trees. Damage to young and old trees can lower the future value of the wood. Road access and a good network of skid trails are important. Good access will improve the efficiency of each thinning and also minimize the damage to crop trees. The selection system can be adapted to encourage the growth of different species. Cutting individual, mature trees in the canopy encourages the growth of shade-tolerant species, such as maple, beech and hemlock, which are growing in the understorey. Cutting groups of trees, in an adaptation called the “group selection system,” encourages the growth of intolerant species, like poplar, and mid-tolerant species, like oak, basswood, cherry and white pine. The group selection system creates sunny gaps in the canopy where these species can grow.

RESULTS FORESTER’S


This system maintains a diverse, all-aged forest with a wide range of species of different sizes and ages. These natural looking forests provide continuous supplies of wood, fuelwood and other forest products, as well as habitat for wildlife and attractive areas for recreation.

Applicability: FORESTER’S


The selection system is well-suited to the mixed hardwood forests. Mixed hardwood forests rely on small-scale natural disturbances, such as lightning, fire, wind, ice storms and disease, to kill individual trees or groups of trees and create the space that young trees need to grow. Deodar, Fir, Spruce and Blue pine forest also in some of the chir forest.

BENEFITS FORESTER’S


• Preserves the genetic diversity of the forest • Full canopy protects site from erosion • Maintains natural-looking, diverse forest • Provides good wildlife habitat and areas for recreation • Generates long-term income and a steady supply of wood products

DISADVANTAGES FORESTER’S


Requires investments in evaluating the forest, selecting and marking crop trees, thinning and harvesting • Assistance from forestry experts is recommended • Large areas are required to generate sufficient volumes of wood and income • Crop trees and regeneration can be damaged during harvest operations

FORESTER’S


Clear Felling System FORESTER’S


The clear Felling system Consists of clear felling parts of the area each year and regenerating it either naturally or artificially The area can be divided into no. of years A method of regenerating an even-aged stand in which a new age class develops in a fully exposed microclimate after removal, in a single cubing, of all trees in the previous stand. Regeneration is from natural seeding, direct seeding, planted seedlings, and/or advance reproduction. Cutting may be done in groups or patches (Group or Patch Clearcutting), or in strips (Strip Clearcutting). In the Clearcutting System, the management unit or stand in which regeneration, growth, and yield are regulated consists of the individual clearcut stand (see Group Selection). When the primary source of regeneration is advance reproduction, the preferred term is Overstory Removal.

Block-clear felling system FORESTER’S


When the area is large you adopt the Block clear felling system for sustainable yield production. e.g If you have 50 compartment and the rotation period of the species is 50 years then number of block you felled in a year is Felling Block=Number of compartments / Rotation Age =1

Clear strip system FORESTER’S


•In this method we divide the area into strips and the felling practice done in these strips.

Clear felling with alternate strip system:

FORESTER’S


The area is divided as in the clear strip system but alternate strips are cut down in the felling time. Procedure: All the trees are harvested in one cutting operation. In a modification of the clearcut system, called the “seed-tree method,” individual trees or groups of trees are left standing to provide seed for regeneration. The seed trees are large-crowned (capable of producing large quantities of seeds) and able to survive in windy, exposed conditions. The clear-cut area can be regenerated by: • Windborne seeds from nearby areas • Seeds from trees left on the site, singly, in strips or in groups • Coppice growth (the shoots that grow from the stumps of trees when they are cut or stressed) • Artificial seeding • Planting seedlings or trees You may need to thin the regenerating forest and protect the young trees from competition with other vegetation and from small mammals.



Clear cutting produces an even-aged forest with trees that are about the same age. Although maple and other shade tolerant species can become established in clearcut areas, Clear cutting strongly favors the growth of shade intolerant species, like jack pine, poplar, cedar and white birch. These species, which need full sunlight, grow fast and quickly dominate clearcut areas.

FORESTER’S


Applicability: FORESTER’S


Clear cutting is a good choice for the irrigated plantation and riverain forests, Where it give little disturbance to eco system. Clearcut system regenerates forest naturally to even-aged growth. Clear cutting is not recommended for general use in the mixed hardwood forests.



• Simplest harvest method with no need to protect remaining seed-trees from damage • Generates highest immediate financial returns • Favors intolerant species, which do not grow well in shade DISADVANTAGES • Makes land more vulnerable to erosion from wind and rain • Erosion can carry silt into streams and rivers, reducing water quality and damaging aquatic habitats • Regeneration in hot, exposed areas can be difficult and may require investments in preparing the site for seeding or planting, thinning, controlling competition and protecting young trees from small mammals • Can reduce the genetic diversity of the tree species in the new forest if the seed came from a few seed trees • Unpleasant to look at and of little value for recreation

SHELTERWOOD SYSTEM (Also Called Controlled by Area)

FORESTER’S


A method of regenerating an even-aged stand in which a new age class develops beneath the moderated microenvironment provided by the residual trees. The sequence of treatments can include three distinct types of cuttings: (1) an optional preparatory cut to enhance conditions for seed production; (2) an establishment cut to prepare the seed bed and to create a new age class; and (3) a removal cut to release established regeneration from competition with the overwood. Cutting may be done uniformly throughout the stand (Uniform Shelterwood), in groups or patches (Group Shelterwood), or in strips (Strip Shelterwood).

Types of Shelterwood System FORESTER’S


Uniform Shelterwood System. As the uniform opening of canopy over the whole area of the compartment with a view to obtain more less uniform regeneration. Group Shelterwood system. In this system regeneration of a compartment is started from natural foci or groups of advance growth or where such foci do not exist, by artificial created foci. Shelterwood Strip System: Felling is done in strips and after number of years enlarge the strips. Irregular Shelterwood System: Modification of Shelterwood selection system, retained the advance growth up to 16″ I Deodar, 12″ in Chir pine (That is also called Punjab Shelterwood system)

Periodic Blocks (P Bs) FORESTER’S


According to the length of the regeneration period, the forest may be divided on the basis of age classes into what are known as Periodic Blocks.

S.No P Bs Age of crop Activity

1. PBI 90-120 Felling/ Regeneration

2. PBII 60-90 Thinning + Preparatory Felling

3. PBIII 30-60 Thinning

4. PBIV 0-30 Regeneration/Seedling/Cleaning/ Also Final felling if require in regeneration

Procedure FORESTER’S


Mature trees are harvested in a series of two or more partial cuts. The cuts stimulate the germination and rapid growth of a new forest in the shelter and the shade of mature trees. The mature trees usually provide seed for regenerating the site, but sometimes regeneration is achieved by seeding, planting or stimulating coppice growth. You will need good roads and skid trails to access the site to complete each harvest. Care is taken at each harvest not to damage the site or the regeneration. This system can involve three different kinds of harvests:

Procedure Contn…… FORESTER’S


1. Preparatory cut The preparatory cut is a thinning operation that gives selected trees room to grow large crowns. Trees with large crowns provide more seeds than trees with small crowns. A preparatory cut is only done if there is a shortage of trees with large crowns on the site. The first harvest is usually done when the trees are 60 to 80 years old. 2. Seed cut The seed cut removes about half the mature trees in the stand. It opens up the stand, allowing sunlight to reach the forest floor, where it stimulates the germination and growth of seedlings. The second harvest is usually done when the trees are 80 to 100 years old. 3. Removal cut The removal cut harvests all the mature trees. It can be done as a single harvest or as a series of partial harvests. The removal cut is conducted after a dense carpet of saplings (trees taller than 1.5 meters) is established in the shelter of the mature trees. By giving the saplings full sunlight, the removal cut encourages the rapid growth of a new forest. The final harvest is usually done when the trees are 100 to 120 years old.

FORESTER’S




The Shelterwood system produces an even-aged, fast-growing forest. It favors mid-tolerant species, such as oak, white ash and white pine, which can germinate in shade but later require some sunshine to survive. This system can be adapted to quickly regenerate maple sugar bushes. Applicability: This system is well-suited to mixed hardwood and conifer forests. The area where lack of sufficient natural regeneration to grow desired species. The Shelterwood system mimics major disturbances, like wind, fire and insects, which create large gaps in the forest canopy where mid-tolerant species can grow.



• Preserves the genetic diversity of the forest • Partial canopy protects site from erosion while new growth is getting established • Maintains some wildlife habitat • Can be used to regenerate oaks which provide food for wildlife DISADVANTAGES • Requires investments in evaluating the forest, selecting and marking crop trees, thinning and harvesting • Assistance from forestry experts is recommended • Can cause loss of habitat for animals that require a mature closed canopy

ACCESSORY SYSTEMS: FORESTER’S


•These systems are applicable in special areas Also Called Special Silviculture systems. •Two Stories High Forest Systems.

•The two stories High Forest of a crop arranges in the different stories on above the other being approximately even aged and Seed origin as opposite of Coppice. •Natural Double stories forest is found in Chir Pine +Oak. •In Plantation, Shisham and mulberry are two stories, Mulberry is planted after its thinning.

COPPICE SYSTEM FORESTER’S


•When regeneration is principally from coppice shoots or root suckers the Silvicultural system is known as the coppice system. •The system is usually adopted for hardwoods when small dimensional stock is required for firewood, basket manufacture, small poles etc. the system is also adopted on arid eroded slopes subject to heavy grazing where natural regeneration is scanty and 100% artificial regeneration is not economic. Types of Coppice system •Simple coppice system •Selection coppice system •Coppice with standards system

silvicultural system

Environment