NATURAL REGENERATION FROM VEGETATIVE PARTS
· Vegetative reproduction or sexual reproduction is the reproduction in plants through some part of the plant body e.g.
§ By coppice
ADVANTAGES OF VEGETATIVE REPRODUCTION:-
i. One plant may produce several plants.
ii. Plants not capable of producing seeds may reproduce.
iii. Plants obtained from vegetative reproduction are relatively fast growing.
iv. Vegetative reproduction may be used for fusing genetically superior trees with inferior ones.
MODES OF VEGETATIVE REPRODUCTION
When certain plants or seedlings are cut from near ground level they produce a flush of fresh shoots. This is coppicing.
Coppice is of two types:-
i. Seedling coppice
ii. Stool coppice
i. Seedling Coppice
Seedling coppice is the mode of producing coppice shoots from the base of seedlings which have been cut back.
ii. Stool Coppice
Stool coppice is the coppice growing out from a stool or from a living stump.
1. Cassia fistula
2. Dalbergia sissoo
3. Morus alba
4. Albizia species
5. Eucalyptus species
6. Salix species
7. Robinia pseudoacacia
8. Ailanthus altissima
9. Azadirachta indica
10. Syzygium cummini (JAMAN)
11. Acacia catechu
12. Butea monosperma (DHAK)
13. Populus species.
i. When a root of a plant is partially or wholly cut to produce a shoot.
ii. Trenches are dug around the isolated trees in a Radius of about 3 meters.
iii. These root-suckers develop into full-fledged trees.
iv. Trees produced by Root-Suckers are easily susceptible to strong winds and have a poor growth.
A portion of a stem, root or branch is planted in the soil. A new shoot is thus produced. e.g.
3. Japance Mulbery
4. Ficus species
5. Grapes species
6. Pomegranate species
7. Chinar species
Roots developed on a girdled portion of a branch. It has two types:-
i. Ground layering
ii. Aerial Layering. e.g.
– Magnolia species
– Gardenia species
The cut part (scion) of one plant is grafted to another (stock). It has two types:-
i. Tongue grafting
ii. Wedge grafting e.g.
It is usually before sprouting season.
– Mango, Apricot, Almond, Palm, Peach, Persimmon, Pears, Apples etc.
A bud is grafted to the bark of another plant. e.g.
– Mango, Apples, Peach, Almond, Palm.
It is usually done in summer season or spring.
i. Pollarding is the process in which a branch of a plant is cut off in order to produce a flush of new shoots.
ii. Pollarding is carried out at a height which is above the browsing reach of animals. e.g.
i. Salix trees in Kashmir Valley.
ii. Grewia oppositifolia in Dir, Bunair.
i. Looping pertains to a cutting of branches.
ii. This is carried out in a number of broad-leaved species for fodder. It is injurious in coniferous species. e.g.
– Quercus species for fodder
– Morus species for sericulture, for rearing silkworm.
Pruning means cutting of branches from the bole in order to maintain the quality of the timber but it should not exceed one-third of the height from the bottom of the tree.
NATURAL REGENERATION UNDER VARIOUS SILVICULTURAL SYSTEMS
· The following are the main silvicultural systems:-
1. Clear felling system
2. Shelterwood system
3. Selection system
1. NATURAL REGENERATION UNDER CLEAR FELLING SYSTEM
i. Under this system, the mature crop is removed in one operation.
ii. The Natural Regeneration of an area gets seeds from the following sources:-
(a) From the adjacent mature forest.
(b) Ripe seed on the trees before felling.
(c) Dormant seed in the clear felling area.
(d) Advance growth.
iii. When the Regeneration comes up, tending and weeding operations have to be carried out in it.
2. NATURAL REGENERATION UNDER SHELTERWOOD SYSTEMS
1. Shelterwood systems are those in which the mature trees are extracted in a series of operations.
2. The initial one being is the seedling and the last one being the final fellings.
3. The basic feature of a shelterwood system is that some trees are retained so that they may act as a supplier of seed in order to enable fresh Regeneration to come up.
4. Different type of shelterwood systems, depending upon the pattern in which the mature crop is removed.
Keeping in view regeneration the different operations carried out under a shelterwood system are as under:-
(a) Seed supply
(b) Light requirement:-
i. Over wood
ii. Middle story
(c) Soil condition
(e) Slash disposal
(h) Protection against damage by wild animals.
(a) Seed supply
i. This is the basic operation for obtaining Natural Regeneration.
ii. Seed supply is ensured when there are enough middle-aged trees.
iii. Seed bearers vary from species to species. e.g. In case of Chir Forest 20 to 30 trees per hectare are retained.
iv. In the hills, seed bearers are retained more on the Ridges in case of conifers so that the entire hill slope has sufficient seed.
(b) Light requirement
i. Over wood
· The trees are removed in such a manner that sufficient gaps are created in the canopy so that regeneration is facilitated.
· Light requirement varies from species to species.
· Young regeneration needs less light than an older crop.
· The secondary fellings are carried out in such as way so as to allow more light.
ii. Middle Storey
· The middle storey acts as a barrier to light. Hence it is manipulated that enough light is admitted for the seedlings to flourish.
· The undergrowth is the lowermost storey.
· It also obstructs light.
· The following methods are used to manipulate the undergrowth:-
– Regular cutting back.
– Control burning
– Use of weedicides etc.
(c) Soil Conditions
The soil should be that a long tap root system can be developed by the seedlings for successful regeneration.
· Control burning destroys the undergrowth, leaf litter etc, thereby eliminating competition for young seedlings.
· Control burning is carried out under careful supervision. e.g. This is carried out in Chir forests for a year or two until a good regeneration comes up.
(e) Slash Disposal
· The disposal of slash so that fire hazards are reduced and the seeds have an easy access to the soil.
· Weeding is carried out before the weeds have suppressed the seedlings growth.
· As a rule in areas which are very prone to frost no weeding is done from October onwards because weeds provide protection against frost.
· The numbers of weeding varies from species to species.
· Weedicides have been effectively used in recent times, in the seedling stage.
· Cleaning is a tending operation carried out in a sapling crop, which involves the removal of inferior growth.
(h) Protection against damage by Animals
· Regeneration has to be protected from two types of animals.
(a) Domestic cattle’s
(b) Wild animals.
(a) Grazing and browsing should be controlled through completely fenced off and watch & ward.
(b) i. Special porcupine fences have to be erected against porcupines and pigs.
ii. Trenches quite deep and wide should be dug out to keep out Elephants.
· The closure period should be neither too long nor too short.
3. NATURAL REGENERATION UNDER SELECTION SYSTEM
1. Under the selection system, the mature trees are extracted singly or in small groups over the entire felling series.
2. In the year following the main fellings, cultural operations are carried out.
3. Climb, cutting is also done.
4. Hence, fellings are carried out in a felling series over a fixed number of years, called the FELLING CYCLE. It may vary from 10 to 20 years.
5. Only selective fellings are carried out. e.g. In tropical moist deciduous forests, the canopy is slowly opened up to obtain regeneration.
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