Seed Processing of Forest Trees

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 The objective of Seed Processing is to produce good quality seeds for sowing. The Processes are Pre-cleaning, Pre-curing, Cleaning.

Pre-cleaning involves cleaning of twigs, barks, leaf litter and other impurities before they are sent for extraction. It can be done by hand and by flotation and fruits be separated by blowing and winnowing.

Pre-curing involves the deliberate storage for ripening of seeds and slow air drying of seeds/fruits.

Cleaning of sound seeds from impurities can be done by screening and sieving,sorting,winnowing,flotation. Screening and sieving remove almost all impurities which have different size than the hole in sieve or screen. Sorting according to length may remove longer and shorter impurities. Cleaning by winnowing is a common practice.Likewise, Flotation method can be used to separate out impurities having different specific gravity than that of seed.

Seed Collection of tree species

Seed collection is very important part of the plantation project or to fulfill the objective of afforestation and reforestation.

The seeds should be collected from the selected tree following different guidelines. The seeds should be collected from healthy vigorous trees of reasonably good form that are making more than the average growth.The seeds produced by immature and mature trees are sometimes infertile so middle aged trees has to be chosen for collection.Poorly deformed, diseased, abnormal, insect infested trees has to be avoided. The seedlings that are produced from the isolated trees of naturally cross- pollinating species,( are likely to be self pollinated ) are weak or malformed and seeds few with low viability. Dominant and Co-dominant trees are mostly chosen and vigorous wolf-trees are also avoided.

Bamboo and Rattans

BAMBOOS are tall, perennial, arborescent grasses, belonging to Poaceae family. There are 50 genera and approximately 1326 species generally inhibiting the humid tropical, sub-tropical and mild temperate regions of the world. It is found  in over 18 million hectares of land, of which 75% lies only in Asia.The rhizomes of the Bamboo may be short and thick and clustered together and produce Bamboo in well defined clumps. Mature Bamboo clumps produced new shoots every year throughout the rainy season. The shoots develop then rapidly within 2-3 months and reach their full height and diameter.

RATTANS belong to the family Palmae/Arecaceae. 600 species of Rattans belonging to 13 genera are reported to be distributed worldwide concentrated in Africa and South East Asia.Rattan is an ideal raw material for cottage industries. Its industrial use is in furniture, walking sticks, polo sticks, umbrella handles, basket making, mats, ropes, and various other articles.

Silviculture of indigeneous tree species in Nepal

Recommending any particular silvicultural system for a species is not a good idea. The silvicultural system for a particular forest stand should be formulated or selected on the basis of species, forest condition, forest owner's objectives and so on.

Sal ( Shorea robusta)

Silvicultural characteristics 

Strong light demander, Good coppicer , Seedling die back due to frost, drought, fire , and dense overstorey, Annual seeders but good seed years after every 2 years, Light winged seeds and seeds dispersed by winds.

Silvicultural Systems

Selection system, Irregular shelterwood system, Uniform shelterwood system, One cut shelterwood system, Clearfelling system, Coppice with standards, Coppice with reserves, Simple coppice.

 

Khair (Acacia catechu)

Silvicultural characteristics

Strong light demander, Seedlings are susceptible to severe frost, Drought resistant, Coppices well unless it is under shade of other species, Seeds produce in abundance, Seeds dispersed by wind and water, requires protection from grazing and browsing.

Silvicultural systems

Clearfelling and Plantation, Simple coppice, coppice with standards, Seed tree method.

 

Sissoo ( Dalbergia sissoo)

Silvicultural characteristics

Strong light demander, Good coppicer, Annual seeder and seeds produced abundantly, Seeds dispersed by wind and water, Older seedlings can tolerate mild frost, Should be protected against grazing and browsing.

Silvicultural systems

Seed tree method, Clearfelling and plantation by Taungiya, Two storyed high forest system, Simple coppice, Coppice with standards, Coppice with two rotation system.

 

Chilaune ( Schima wallichi)

Silvicultural characteristics

Not frost hardy,Coppices very well, Good seed year are frequent , Winged light seeds dispersed by wind, Moderately shade tolerant but later it benefits from full overhead light, Capable of colonizing plantations of other species.

Silvicultural systems

Simple coppice, coppice with two rotation, Coppice with standards, Selection coppice, Selection system.

 Katus (Castanopsis indica )

Silvicultural characteristics

Moderately shade tolerant, Frost hardy, Benefits from overhead light in later stage, Young seedlings are frost tender, Coppices well.

Silvicultural systems

Simple coppice, Coppice with two rotation, Coppice with standard, Selection coppice, Selection system.

Deodar( Cedrus deodara)

Silvicultural characteristics

Shade bearer and young seedlings benefit from side shade, Winged Seeds dispersed by wind, Young seedlings don't suffer from frost, Very sensitive to fire, Good seed years after every 3 years, Most of the seeds fall close to the parent tree, Profuse regeneration in favorable sites.

Silvicultural Systems

Single tree selection, Irregular shelterwood system, Uniform shelterwood system (40-50 seed trees/ha).