Regeneration of Forest
The renewal of a forest by some means (e.g. natural or artifcial) is known as regenerations. The regeneration has been defined in a number of ways by several workers. Regeneration of Forest
1) “The renewal of a forest crops by natural or artifcial means; also the new crop so obtained”.
2) Regeneration as, “The renewal by self-sown seed or by vegetative means.” It is of two types viz., Natural regeneration and Artifcial regeneration.
Regeneration of Forest
Methods of Regeneration:
There are following methods of regeneration of forest:
A) Natural Regeneration,
B) Artifcial regeneration and
C) Natural regeneration supplemented by Planting.
However, first two methods are most important in regeneration of forests.
Regeneration of Forest
A) Natural Regeneration:
The renewal of a forest crop, by self-sown seed, or by coppice or root-suckers, also the crop so obtained or also it can be defned as Reforestation of a stand by natural seeding.
B) Artificial Regeneration:
It is defined as the renewal of a forest crop by sowing, planting, or other artifcial methods; also the crop so obtained or the renewal of a tree crop by direct seeding, or planting. Site Preparation for Regeneration of Forest
The site preparation is used to create an environment suitable for establishing the desired tree species
1) To get rid-off logging slash or other debris
2) Reducing competition and animal habitat
3) To prepare a mineral soil seedbed
4) To improve drainage of surface and upper soil horizons and reduce the compaction
5) To create a more favorable micro site on harsh sites
6) To take measure to control disease.
Site Preparation Methods:
Following four methods of the site preparation are commonly used all over the world:
i) Mechanical
ii) Prescribed Burning
iii) Chemical and
iv) Combinations of the three.
Regeneration of Forest
i) Mechanical Method of Site Preparation for Regeneration: There are several methods employed for carrying out the site preparation mechanically. Following are some of the common mechanical methods:
a) Logging: This is the most common practiced method of site preparation. In this method,logging equipment is used for removing the vegetation and slash.
b) Scalping: This is nothing but the site preparation by hand cleaning.
c) Mechanical Cleaning: In this method self-propelled or the tractor drawn equipment are used.
ii) Prescribed Burning: Fire is a nature’s principal method of preparing sites for a new stand.
iii) Chemical Method: The herbicides may be used in new burns and the cuttings, non or poorly stocked parts of plantations, or in existing bushy fields.
Factors Affecting the Choice of Forest Regeneration Method
It is very important to make a choice of method of site preparation. In this case, there are, a number of factors infuencing the choice of site preparation method. Following are the seven factors which play a vital role in the choice of method:
1) The nature of existing ground cover,
2) Physical site factors,
3) Site preparation requirement,
4) Available labour and equipment
5) External constraints,
6) Environmental impacts and
7) Cost incurred in the operation.
Natural Regeneration of Forest
Regeneration from seed or vegetative parts may observe in Natural Regeneration. Reforestation of a stand by Natural seedlings
1) Natural Regeneration from Seed: Successful natural regeneration from seed depends upon Seed production, Seed dissemination, Seed germination, Establishment and seedlings.
Regeneration of Forest
a) Seed Production: Seeds are cultured ovules, which contain the embryo. An embryo is a miniature plant consisting of seed leaves (cotyledons) attached to rudimentary stem (hypocotyl) with a growing tip (Plumule) and a root tip (radicle) at the other end. Seed production depends upon various factors such a species, age of tree, site, weather conditions, season of maturity, alternate bearing, attack of pests and diseases and birds.
b) Seed Dissemination: For the continued existence of a species, it is necessary that seeds are carried away from the parent plant, because seeds germinating immediately below the parent tree commonly do not get established. Seed dissemination gives young seedlings a better chance of survival for they are saved to a large extend from competition with the parent plant. The means of dispersal adopted by the seeds of different species vary widely. The four important agencies by which seed dispersal is secured are i) Wind, ii) Water, iii) Animals, iv) Explosive mechanism or ejection mechanism in fruit itself.
Regeneration of Forest
c) Seed Germination: Germination of seed depends upon several internal and external factors such as Permeability of seed coat, Availability of moisture in seed, Oxygen, Nature of embryo (dormancy), Temperature, Moisture in soil, Oxygen and light. Besides this some factors,
1) Age of Tree,
2) Flowering Phase,
3) Sound or health of seed condition,
4) Coppice origin trees,
5) Size of seed,
6) Plant per cent,
7) Type of dissemination,
8) Soil type / nutrition,
9) Pest and disease,
10) Non insect pests.
d) Seedlings Establishment: Successful establishment of newly germinated seedlings in suffcient number as a member of forest crop is undoubtedly, the weakest link in the whole chain of process (a to c) which make up the regeneration of forest crops. The Factors Responsible, for Seedlings Establishment are as:
1)Climate: Light / moisture rainfall / temperature / frost
2) Edaphic – Soil / nutrient / aeration / texture / structure.
Regeneration of Forest
II) Natural Regeneration by Coppice and Root Suckers:
Coppice : Stool shoots generally arise from the adventitious buds formed between the wood and the bark of the stump and are comparatively short lived than those produced by dormant buds. These
shoots are called coppice shoots.
Classification of Coppice Regeneration:
1) Seedlings Coppice
2) Stool Coppice and
3) Root collar Shoots
4) Pollard Shoots
Natural Regeneration by Root Suckers: Shoots arises from the roots, may occur naturally or artifcially.
Regeneration of Forest
Regeneration by Artificial Method
The deforestation is still continuing and takes a heavy toll of forest wealth. This not only affects the forests but the wildlife and the whole ecosystem also. Deforestation is on alarmic rate (1.5 million hectare every year). For carrying out artifcial regeneration, there are some preliminary considerations which are urgently needed.
Basic Steps in Artificial Regeneration:
1) Choice of Species:
i) The choice of species is very important in artifcial regeneration. Therefore, before choosing the tree species, the purpose of growing the trees has to be specifed.
ii) Climate and microclimate: The choice of species depends upon the prevailing climatic and micro-climatic conditions.
iii) Soil requirements:
a) Wet soils – Salix species, Populus species, etc.
b) Water – logged soils, Eucalyptus robusta, E. saligna etc.
c) Sandy loam – Albizia procera, Acacia nilotica, Dalbergia sissoo, etc.
Regeneration of Forest
iv) Market faci ities :
v) Growth rate: Fast growing tree species – Acacia nilotica (Babul), Leucaena leucophala (Subabool), Melia azedarach (Bakain), P. deltoides (Poplar), Salix species (Willow)
vi) Availability of Exotics: In simple it meaning pertains to, not native to the area of question. The exotic can be described as “an organism in an area which is not native of the area but has its origin in some other region. For example, Eucalyptus species, Leucaena leucocephala, Robinia pseudacacia, Populus deltoides etc.
vii) Base of extablishment.
viii) Management objectives. The artifcial regeneration depends upon the objectives of management.
ix) Site conditions: The site is the complex of physical and biological factors of an area that determine what forest of other vegetation may ^arry.
x) Succession: The succession is the gradual replacement of one community by another in the development of vegetation towards a climax.
xi) Cost of growing: This is also very important factor affecting the choice of species.
xii) Availability of seed /propagation material : The seed source should be sound.
Regeneration of Forest
2) Choice of Method:
The success of artifcial regeneration depends, to a great extent upon the choice of method. There are mainly two methods of this regeneration, viz. i) Sowing and, ii) Planting.
i) Sowing: Sowing, in the simplest words, is the process of scattering the seeds in a particular place e.g. nursery bed, field etc.
Advantages of Sowing:
a) It is the cheapest method and costs less,
b) Sowing is direct method and no other complications,
c) It takes less time and thus the work is completed soon,
d) In sowing method, there is no question of disturbances of roots.
e) Sometimes, sowing is done directly in the feld (in forests), and hence it does not require any nursery.
f) The sowing being the simple method, is supposed to be less cumbersome.
ii) Planting: Planting is another method of artifcial regeneration. However, planting is described as the transferring nursery stock to the planting site as contrasted with transplanting in the nursery.
Advantages of Planting:
a) More Success,
b) Less seed needed
c) No damage,
d) Cheaper weeding
Disadvantages of Planting:
a) Need of nursery
b) Disturbance of roots
c) Time consuming,
d) Need of skilled labour
e) Incurred high costs
3) Site Selection: The selection of site is also a crucial factor in artifcial regeneration. There are several factors which affect the site preparation.
Following are the factors which are essential to carry out the preparation:
1) Ground Cover:
2) Physical Factors: a) Topography, b) Exposure, c) Soil type, d) Erosion hazards, e) Size of treatment area and f) Access
3) Preparation requirement: To create a suitable environment for establishment of desirable species.
4) Man Power and Equipment: The site selection and preparation methods require good skill
and useful equipment.
5) External Constraints:
a) Legal responsibilities,
b) Smoke management guidelines,
c) Proximity to sensitive areas and
d) The attitude of adjacent farmers / land owners.
6) Spatial Arrangement: This is also called as Spacing.
Artificial Regeneration by Vegetative Method:
Planting material besides seeds for e.g. Bare root seedlings, containerized seedlings, cuttings, layering, rhizomes, suckers, offsets, bulbs, corms are also used for vegetative propagation material.
Propagation by Cuttings:
Cuttings are of two types, 1. Stem cutting 2. Root cutting
1. Stem Cutting: Very few species response well for this method. The species, which easy to root are suitable for this method of planting. Particularly species of di-cotyledons group having active cambium layer e.g. Shisam, Nimbara Drumstick, Mulberry Inga dulsis, Dhaman, Pangara, Pimpal, and Banyan Tree etc.
Depending upon the maturity of stem cutting are grouped into:
i) Hard Wood Cutting: Mature woody branches are used.
ii) Soft Wood Cutting: Recently mature branches are used e.g. mulberry-Inga dulsis.
iii) Root-cutting: Roots are used for preparation of cutting e.g. Sandalwood, Pangara.
2. Stumps: In few species, stumps are used for planting e.g. Teak, Shivan, Shisam, Cassia spp. Stums are easy to transport, require less space and can be transported to long distance. These are prepared at the time of planting operation or just before planting operation. Fresh uprooted seedlings are used to transplant easily. 20% stem portion and 80% taproot is kept while preparing the stump. Fine edge knife or implement is to be used so as to avoid the damage, stem portion is cut 5 to 6 cm above the collar region is kept intact and remaining portion or roots are cut to prepare stump. The stumps are then packed in bundles, keeping stem portion on one side and roots on another side, the stumps should
be transported immediately. For transportation stumps are covered with moist gunny bag cloth to avoid desiccation. They can be transported within 2-3 days without much loss.
These stumps are planted on start of monsoon after 3-4 rain showers when soil becomes sufciently moist and soil temperatures are warm. Stumps are planted by preparing small holes in slating portion with the help of crowbar so that new shoot will rise straight. Then the stumps are inserted inside and soil is pressed frmly so as to avid water stagnation in the hole. The cooler region is kept just near to the soil surface.
Regeneration of Forest
3. Root Suckers: Root suckers can also be used for planting purpose e.g. Pomegranate, Kokum, Salaim Anjan, Shisam, Nimbara, Pangara, Erythrona etc. The layers, grafted plants, budded plants can be used to prepare planting material. These all are only used in forestry for conservation of superior genotype. It is used for commercial plantation as they are short lived, spreading and not develop long straight (trunk), particularly suitable for timber purpose.
Regeneration of Forest
Planting by root cuttings in sandal wood, pangara. Planting by root suckers e.g. Pala, Anjan, Pomegranate, Kokum, Salai, Shisam, Nimbara, Erythrina Supersa.
Regeneration of Forest
