Introductory Agroforestry

Exercise 3

Exercise 3: Cultivation and Nursery Practices for Grewia Optiva

Learning Objective: Economics of Cultivation - Nursery and Plantations of Grewia optiva Drumm.



Plate 3.1 Grewia optiva tree

Botanical Name: Grewia optiva Drumm.
Common Name: Beul, Dhaman
Family: Tiliaceae

Description:

• It is a very popular tree of the farmers of the sub-Himalayan tract for its fodder and fibres.
• A full grown tree is moderate sized with spreading crown, reaching a height up to 12 m with a clear bole of 3-4 m and a girth of about 80 cm.
• Bark is smooth and whitish-grey.
• Flowers 1-8, solitary and axillary, petals yellow or white.
• The fruit is a fleshy drupe, 2-4 lobed, olive green when immature and black when ripe, and edible.
Distribution:

• It is distributed from the foothills of the Western Himalayas from Jammu and Kashmir to Nepal up to 2000 m elevation.
• It is not a common forest tree and is generally grown on field boundaries or terraces raised by the hill farmers.
Site factors:

• It is a tree of sub-tropical climate.
• In its natural habitat, the maximum shade temperature seldom exceeds 38oC and the minimum rarely drops below -2oC.
• Tree is hardy and grows on a variety of soils. Sandy loam soil with adequate moisture supply supports good growth.
Phenology:

• Leaf-fall - March-April
• Leaf renewal - April-May
• Flowering - April-May
• Fruiting - June-July
• Fruit ripe - October-November
Silvicultural characteristics:

• Strong light demander
• Require complete over head light
• Seedling suppressed by weed
• It is frost hardy tree
• Young seedling dieback due to severe frost
• It coppice very well
• Susceptible to fire and browsing
Natural Regeneration:

• Natural regeneration occurred sporadically
• Seed coat is hard
• Germination take place after the seed get soaked for more than 12 hours
• Long tap root is formed during the first year which is longer than the shoot length
Artificial regeneration:

Grewia optiva can be propagated by seeds, transplanting of nursery raised seedings, by cutting or planting stumps.

Seed collection and storage:

• The fleshy drupes are edible,
• A substantial quantity of fruit crop is devoured by the birds, if seed collection is delayed.
• The fruits are not borne on the current year's shoot, tree lopped completely do not bear fruits.
• Therefore, trees reserved for seed production should either not be lopped at all or if necessary only partially.
• The fruits are rubbed and washed in water to separate out the seeds.
• Each fruit contains 2-4 seeds;
• There are about 12,000 to 15,000 seeds per Kg.
• The seeds have a hard testa and can be stored well for at least a year without any appreciable drop in vitality.
Nursery Technique:

• Pre-treatment of seed is necessary as seed coat is hard.
• Sowing should not be done on raised beds as moisture needed for germination.
• The dibbling method of sowing with twice a day irrigation proved to be the best in germination percent.
• The seed is sown in March-April, about 2 cm deep in lines 15 cm apart
• Watering is done regularly till germination is over. Germination starts in about 10 days and takes a month to complete.
• Sowing in March results in prolonged and scattered germination with heterogeneous stock.
• The seedlings are spaced about 10 cm apart in lines.
• The growth of the seedlings is fairly fast and they attain a plantable height of 30 cm or more by July.
Planting Out:

• Planting is done at the onset of monsoon, late planting generally fails.
• Seedlings uprooted from the nursery with balls of earth are wrapped in moist gunny bags and transported safely.
• Planting is done in 30 cm3 pits at a spacing of 4x4 m for block planting and 4-5 m for single row planting along the field bunds. For stump planting 15 month aged seedlings are used.
Vegetative Propagation:

• It can be successfully propagated by cuttings, under intermittent mist.
• Soaking the cutting base for 20 hrs in 100 mg/litre IAA gave a maximum rooting of 77.5 % in June.
• The technique used for mass multiplication of cuttings for plantation and seed orchard establishment.
• It can also be propagated by air layering.
ECONOMIC IMPORTANCE

Small timber:

• The wood is white, heavy, hard, elastic, strong and fine-textured.
• It is used for oar-shafts, axe-handles, shoulder poles, cat frames, bows and several other purposes, where strength and elasticity is required.
• The wood is difficult to saw when green but also difficult to work by hand after seasoning. It is reported to be suitable for paper-making.
Fibres:

• The bark yields a fibre of inferior quality used for cordage.
• The elastic branches are used for making baskets.
Fuel-wood:

• Though used as a fuel wood, not liked very much because of the foul foetid smell it emits on burning.