REGENERATION
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Definition
Methods/Types of Regeneration
Natural Regeneration
Sources of Natural Regeneration
Natural Regeneration from seeds
Seed production
Seed Dissemination
Seed Germination
Seedling Establishment
Ecological Requirement for Natural Regeneration
DEFINITION
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... replacement of the old forest crop with a crop of nwer generation
... new growth that develops in a forest crop before felling is generally
called an advance reproduction or an advance regeneration
... renewal of a forest crop by natural or artificial means
Methods/Types of Regeneration
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Natural regeneration
Artificial regeneration
Assisted natural regeneration
Natural Regeneration
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Refers to the natural process by which plants replace or re-establish
themselves.
... regeneration by self sown seeds, coppice or root suckers, i.e. without
human interference (Cremer, 1990)
Regrowth, which occurs naturally after stress or disturbance (Temple and
Bungey, 1980). It may be growth from seed of both pioneer or permanent
species, or growth from lignotuber (e.g. Eucalyptus spp.), rootstock
(Melaleuca spp.), etc. remaining in the ground.
Sources of Natural Regeneration
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from seeds or by sexual means
from vegetative parts or by asexual means
Natural regeneration from seeds:
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seed production
seed dissemination
seed germination
seedling establishment
Seed production
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Species:every year (Tectona grandis, Dalbergia sissoo, Acacia nilotica)
alternate years (Sorea robusta, Terminalia alata)
atfter a long interval (Abies pindrow, Anoquissus latifolia)
Flowering periodically (Strobilanthes, bamboos)
Age of the tree:most abundant and best quality seeds produced after attaining a certain
height
best seeds are produced by middle-aged and medium-sized trees
young as well as old trees produce seeds of less geminative capacity and
seedling vigour
Soil condition:a base rich soil stimulates seed production
over abundance of nitrate retards seed production
Seed production
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Climate:a warmer climate favours early and heavy seed production
hot and dry years are followed by heavier crop of seeds
late frost and rain storm are harmful
Crown and root space:large and well developed crown bears more seeds
judicious thinning contributes to crown development and creates
space for root development
Others:fire injury lessens the mass production of seeds
fungus and insect reduces the seeds production
girdling too has a negative impact on seed production
Seed dissemination
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wind
water
gravity
animals
explosive mechanism
Seed dissemination
By WIND
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seeds are winged, hairy or light
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examples: Dipterocarpus, Terminalia, conifers, Dalbergia, Acer,
Betula, Rhododendrons, Oroxylon, Bombax, Popolus, Salix
By WATER
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Trees grow near water courses or by the water body
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seeds are able to float
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examples: teak, Acacia, catechu, Tarmarix, Casuarina
By GRAVITY
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seeds are heavy
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seed coats are hard
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examples: oak acorns, Juglans regia and diospyros
By ANIMALS
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seeds are stony which can pass with the dung
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examples: Bronssonetia, Trema, Vitex, Morus
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Sticky seeds (Desmodium, Flemingia, Andropogon, Rumex)
Seed dissemination
By EXPLOSION
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seeds are covered by pods
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seeds pods are dehiscive
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examples: Viola, Oroxylum, Geranium