Silvicultural System of Concentrated Regeneration
a) Clear Felling System:
i) Clear Felling System:
Defined as 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.
a) Deptt. plantation
b) Taungya i) Deptt. ii) Leased iii) Villages
a) Seed stored in the area
b) Received from outside.
Advantages of Clear Felling System:
1) Simples and not require a high degree of skill in marking for felling.
2) Yield / Unit area is more, cost of felling and extractions is less.
3) Increasing the proportion of valuable species and introducing fast growing exotics.
4) Easy supervision of all operations / regeneration felling, conservation, extraction.
5) Does not involve any damage to new crops.
6) Reduces cost of regeneration operations and shortening the rotation.
7) The coupe (area) can be opened up for growing soon.
8) More cleaner and cylindrical boles and trees.
9) Ideal for mechanization.
10) Success or failure for regeneration work is absolutely clear by the end of second year.
Disadvantages of Clear Felling System:
1) Most Artificial
2) Great danger of deterioration soil and the soil erosion increases due to exposer and area till the canopy closes
3) Problems of invitation of weeds and grasses / fire hazards
4) Less resistant to damages by wind (even aged crop)
5) Devastated appearance of large clear felled areas
6) It sacrifices all the immature trees when applied first
ii) The Clear-Strip System:
It is defined as a Silvicultural system in which clear felling is done in the form of strip which progress successively in one direction (against prevailing direction of wind) across the regeneration area. It is also known as Progressive strip system.
Advantages of the Clear-Strip System:
In addition of Clear Felling It does not deteriorate the site and maintains the aesthetic beauty of the area, while it is difficult for protection against fire, grazing etc.
iii) The Alternate Strip System:
It is defined as a Silvicultural System in which clear felling is done in the form of strip and the clean filled strips alternate with un-felled strips of similar width though sometimes these may be narrower or wider also.
b) Shelter Wood Systems:
As the regeneration is obtained under shelter of the over wood is called Shelter Wood System and as over wood is removed in two or more operations, these are called as systems of successive regeneration forestry.
In other word shelter wood systems involves gradual removal of the entire stand in two or more successive feelings which extend over a part of rotation.
i) The Uniform System: Defined as silvicated systems in which canopy is opened up for regeneration uniformly over the whole compartment in one operation.
Advantages of the Uniform System:
1) Little risk of soil deterioration and erosion
2) Marking and feeling of trees is simple
3) Invitation of weed is not their
4) Young plants are protected against adverse conditions e.g. frost, cold, wind
5) Good establishment of superior species
6) Insects injuries are reduced considerably
7) New crop appears before the old one is harvested, rotation is shortened
8) Little loss of potential wood production
9) Easy supervision
Disadvantages of the Uniform System:
1) Damages may cause to regenerated seedlings while feeling of retained trees
2) Required knowledge to maintain canopy / shade
ii) The Group Systems:
Silviculture Systems in which regeneration felling, instead of being done uniformly all over the compartment are carried out in scattered groups
Advantages the Group Systems:
1) Young crop develops in a more natural way than it does in Uniform Systems
2) Protection against frost and insolation
3) Damage by felling to regeneration is avoided during the earlier stages by regulating the fall of trees towards the un-filled frost.
Disadvantages the Group Systems:
1) In hilly terrain area it is difficult
2) Marketing of feeling trees is difficult
3) Supervision and control becomes difficult
4) Considerable losses in hilly areas to regeneration due to rolling/ sliding logs of timber
5) Requires intensive working
6) Not possible in India 30 years on one place
iii) The Sheltered Wood Strip System:
Silviculture System in which regeneration, felling is done in the form of strips successively from one side of the compartments progressing against direction of wind.
iv) Strip and Group System:
Modification of sheltered wood strip system in which fellings done in strips confirm in the group system instead of the uniform systems
v) The Irregular Sheltered wood System:
Silviculture System in which regeneration felling’s on the pattern of group system but as the regeneration period is long, the crop produced is uneven aged or irregular.
vi) Indian Irregular Shelter Wood:
Defined as Silviculture System in which the crop to be regenerated is opened up irregularly and the resultant crop in un-even aged. It provides for retention of groups of well-grown poles and immature trees as part of future crop and it permits the adoption of selection felling on step or rugged portions of compartment being-worked under uniform systems.
vii) Agner’s Blender System :
Silviculture System in which regeneration felling is carried out in narrow strips extending in east west direction and developing from north south object. Offered side protection to regeneration, modification of sheltered strip systems
vii) Wedge Systems:
Silviculture System in which the strip instead of being one end, is located in the middle of its length coming in the wind direction.