A clear felling system is a high forest silvicultural system. It involves successive clear felling of equal or equi-productive areas in one operation, followed by obtaining regeneration either naturally or artificially.
Methods of obtaining regeneration
- Through Artificial Regeneration
- Through Natural Regeneration
Through Artificial Regeneration
- Departmental Plantation – Mainly raised by range staffs engaging local labors.
- Taugnya – Plantation in which forest crops are raised along with agricultural crops. Example; Tamagadhi. May be departmental taungya, village taungya and leased taungya.
Through Natural Regeneration
- Seed stored in the area– Frost hardy species having viable seeds can be regenerated in which seed ripening should coincide with felling. E.g Teak
- Seed received from outside – Seeds reach the area from outside through different means. In Pakistan, babul seeds are seen flooded with water.
- Natural regeneration from advanced growth – Established seedlings, sapling, and young pole of desired species already present in the coupe before clear felling. E.g Sal
Types of clear felling system
- Block-clear felling system
- Clear felling in patches
- The clear strip system
- The alternate strip system
Block-clear felling system
In this system, successive clear felling and regeneration are carried out in a particular area. This system is adopted in large areas for sustainable yield production. If “n” be the number of compartments (blocks) in an area and “N” be the rotation age of species, then,
The number of felling blocks = No. of compartments/ Rotation age
|Block I||Block II|
|Block III||Block IV|
Clear felling in patches
It is applied on irregular terrain or even age stands that lack uniformity.
The clear strip system
In this silvicultural system, clear felling is done in the form of strips that progress successively in one direction across the regeneration area. Therefore, it is also known as a progressive strip system.
The felling is usually done against the prevailing direction of the wind across the regeneration area. The area is divided into cutting sections which in turn are divided into a number of strips. In this case, the seeds from the un-felled area may be disseminated on the cleared strip.
The width of the strip depends upon the distance to which the seed can be disseminated by wind so that all part of the clear felled area receives sufficient seeds for regeneration.
Application – Pinus Keshia in Assam.
The alternate strip system
In this silvicultural system, clear felling is done in the form of strips in which clear felled strips alternate with un-felled stripes. The stripes may be of similar width or sometimes may be narrower or wider. Thus, varies from place to place.
The un-felled stripes provide protection against wind and also supply seeds to felled strips. This method has been seen applied in Sal forests of Dehradun with clear felled strips of 12m and un-felled strips of 36m.
- It is the simplest method of all high forest systems.
- As felling is concentrated, the yield per unit area is more and the cost of felling & extraction is low.
- Even aged forests can be regenerated in the area.
- The distribution of age class is very regular.
- Trees with cleaner and more cylindrical boles having fewer knots can be obtained.
- There is no damage to the new crop by felling as most of these operations are completed before the new crop regenerates.
- There is a provision for the complete overhead light. This greatly helps in the regenerations of species that are strongly light demanders.
- The entire crop is regenerated in one operation. So, it reduces cost and rotation making the work quicker.
- It does not require a high degree of skill.
- It makes easy supervision of operations.
- Due to early regeneration early, the coupe can be opened up for grazing soon.
- The success or failure of regeneration is clear by the end of the first year or in a few years.
- Desiccation and general degradation of the soil as a result of exposure to the sun, air, and water.
- The growth of grass and weeds may prove a hazard to regeneration operations.
- Multiplication of insects, fungi, bacteria, etc which are harmful to the young crop.
- It sacrifices all immature crops that may be still putting on valuable increments.
- This system is not wildlife-friendly, due to habitat loss animals migrate to other places.
- Less utilization of growing space and site factors.
- An even-aged forest is produced which is more prone to attack by insects, pests, fungi, and damage by snow, wind, and even frost as compared to an uneven-aged forest.
- Less annual yield than uneven-aged crops.
- This is not suitable for the hilly and sloppy area as there is an ever-present danger of landslides.
- Aesthetically, this system is not considered friendly.