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FOREST NURSERY TECHNIQUES

To make an afforestation /re-forestation campaign a success a well stocked nursery raised on scientific lines is a pre-requisite. Beside the adverse biotic and edaphic  factors, failure of most of the planting campaigns in the country can generally be traced back to poor stock raised in ill-equipped nurseries by the staff which often ignorant of the modern techniques of nursery rising and its management. The result is the most of the planting material thus produced is not up to the mark and is much below the requisite international standards. It is weak, whippy, diseased and sometime even totally unfit for planting. Thus, although millions of plants are planted in the state forests and are also distributed to the people, on the whole percentage of success and survival is not satisfactory. It is therefore highly imperative that maximum attention is paid to raising o f nurseries on scientific lines. This information has been assembled to familiarize the foresters and others with the latest technical know-how in this particular aspect of forestry practices.
SEED COLLECTION: Observations over a number of years indicate that seed can be collected from different localities in Pakistan at different times of the year as under:
Important tree species and period of their seed ripening
NAME OF SPECIES
PERIOD OF RIPENING OF SEED

A: CONIFERS
Abies pindrow (Fir)
September-November
Cadrus deodara (Deodar)
September-November
Picea smithiana (Spruce)
September-November
Picea gerardiana (Chalgozapine)
September-November
Pinus roxburghii (Chir pine)
April-May
Pinus wallichiana (Blue pine)
September-November
Pinus helepensis (Quetta pine)
October-November
Cupressus arizonica (American cypress)
April-May
B: BROAD LEAVED SPECIES
Acacia miseata
November
Acacia nilotica
June-July
Acacia Senegal
June-July
Aesculus indica
October-November
Ailanthus altissima
July-August
Albizzia lebbek
December-January
Albizzia moluccana
May-June
Albizzia procera
March-April
Alstonia  scholaris
May-June
Azadirachta indica
June-August
Bauhinia variegate
May-August
Bombax ceiba
May-June
Broussonetia  papyrifera
July-September
Cassia faistula
May-June
Cedrela  toona
June-July
Dalbergia sissoo
January-February
Eucalyptus citriodora
March-April-September
Eucalyptus camaldulensis
September-October
Eucalyptus microtheca
September
Eucalyptus tereticornis
September-October
Jacaranda mimosifolia
January-March
Juglans regia
September-October
Leucaena  leucocephala
November-December
Mangifere indica
July-August
Melia azedarach
December-January
Morus alba
April-June
Parkinsonia aculeate
May
Prosopis  cineraria
June-August
Quercus incana
December-January
Quercus semcarpifoli
July-August
Robinia pseudoacacia
August-September
Tamarix aphylla
December-January
Terminalia  arjuna
February-May
Zizyphus  mauritiana
March-April

First of all plus trees of an age ranging from 20-60 years have to be marked because the seed from younger trees or over mature trees show less viability and germination percent. A tree qualifies to be a plus if it is healthy, straight-boled and dominant, with minimum number of branches. Cones while still closed are collected from the tree pods are also closed. Drupes and berries are collected when ripe. These are spread out in the sun where they open in 7-10 days. The seed is separated from the inner material and thoroughly cleaned. It has been found that weight of the clean and healthy seed varies according to the localities and is directly efficiency linked with weather  conditions, of labour, distance involved and quantity of seed produced in a cone and of course the good or bad seed years.
EXTRACTION AND CLEANING: Seeds of most conifers have to be dewinged after extraction by rubbing them between moistened hands or rubbing a mesh by the hand or power brush: packing the seeds loosely in a sack against trees or walls. Dewinging machines are also available but are required only for large wale operations.
Screening: Seeds can be screened satisfactorily by sifting them through screen either dry or with running water. The screen must be of proper size to separate the seeds from the chaff or other materials.
Fanning: Fanning is used to remove wings or light chaff as well as for separating the empty seeds from filled ones. This method is not practicable with light seeds from filled ones. This method is not practicable with light seeds such as those of eucalyptus, poplars, willows etc. the speed of the fan can be adjusted to suit the size of the seeds.
Floating: Seeds of most pulpy or flesh fruit can be cleaned by floating in water after depulping. Sound seeds usually sink; empty seeds, skins and pulp either float or sink more slowly than the sound seeds. The usual method is  to place a quantity of macerated fruit in a large wash tub tiled slightly and given a direct stream of water crating a rotatory swirl. The material in the bottom is starred lightly. The pulp and light seeds will be brought to the surface and carried over to the edge of the tub by over flow water. By this method seeds of Junipers can be easily separated from the pulp.
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