Sunday, July 12, 2015

SOME VARIETIES of WOODS of Indian subcontinent



SOME VARIETIES of WOODS of Indian subcontinent
Post 126   by Gautam Shah ➔

With quality woods getting scarce due to deforestation and restrictions on export and import, attention is now on low quality woods. These are few species that were till now used for low quality products and in rural areas. The species have individual drawbacks that need to need to be technologically handled. This is not an exhaustive list, many such species exist, and are used for specific products. Such species of wood are found across the Indian subcontinent (India, Pakistan, Bangladesh, Sri Lanka, Nepal) or geographically very large subregions of it. These are tropical varieties and may be found in similar climate zones in other parts of the world.
Neem Tree in Rajasthan India

NEEM (Azadirachta indica) is also known as Neem, Nim-tree, Sanskrit Nimba, or Indian Lilac. Neem is also called ‘arista’ in Sanskrit to mean ‘perfect, complete and imperishable plant.’ The Sanskrit word Nimba derives from ‘nimbati syasthyamdadati’ meaning ‘to give good health’. It is a tree in the mahogany family Meliaceae. Originally from Burma (Myanmar), but now found almost everywhere in Indian subcontinent, and Iran. It is now planted in parts of Africa and Australia. Neem trees can grow on village outskirts (Gochar or cattle grazing fields), farm borders, and roadsides, singly or as plantation. For the Cart Festival (Rath-Yatra) of Lord Jagannath at Puri, Orissa, India, Specific Neem trees are selected after religious ceremony, cut and used for statues and huge wood cart.
Praying before a tree prior to cutting for Lord cart for Rath-Yatra

Neem trees grow very fast in tropical climates. The tree grows to substantial maturity in a decade, and fully grown can be 12 to 18 mts. tall and can have trunk girths of 1.8 to 2.4 mts. It has a straight trunk and long spreading branches that forming a crown of 20 mts. across. The trunk and branches both offer good wood. It is an ever green tree, providing green leaf for fodder for sheep and goats, whereas its dry leaves and seeds provide organic fertilizer with biocide properties.
 
Grains of NEEM timber

The sap wood of Neem is of lighter colour and the heart wood resembles Mahogany, and is of darker reddish to brownish colour. The timber of a fresh cut is dripping wet, but once sawn begins to season well. After three years of natural drying, or plant-based seasoning, wood dries with shrinkage. Neem timber has medium density. It can be worked but its surface cannot take smooth finish, however it can be painted with suitable surface filling primer. The wood is hard, lustrous and aromatic.
 
Neem timber sawn sections

Neem wood was considered rural timber. It is better then Mango wood, due to the compact grain. Its superior toughness and resistant to moisture, termites, other insects like borers and fungi make it a favourite wood for farm implements, carts, house beams and columns, door and window frames, furniture like charpoys (country beds), cart, axles, ship and boat building, helms & oars, tool handles. It is now widely used for plywood making and as inserts in flush-doors and block-boards.
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MANGO tree is of genus Mangifera, and belongs to the flowering plant family Anacardiaceae. Mango is a tropical tree, growing in many parts of the world in as many varieties. The English word mango representing the fruit, (pl. mangoes or mangos) originated from the Malayalam word manna via Portuguese during spice trade with Kerala in 1498.
Mango Tree
Mango Tree
Mango trees are grown in every part of India, as single a farm tree or as an orchid. Trees grow to a height of 35–40 mts., with a crown radius of 10 mts. The trees are fairly very sturdy, and bear fruit for very long time. The trunk girth is 1.50 mts. So provide large section of timber. The heartwood is mainly golden brown, to pale-whitish. Sapwood may not be very distinct. The grains are straight, interlocked, curly or mottled. The grains show coarse texture. Mango timbers have porous end grain, which restrict its use for lathe turned articles. Timbers with interlocked or wild grain have tear-out problems during planning or machining. Resins have a tendency to bind on the heated saw or planning blades. Some varieties have high silica content that can dull the cutting edges. 

Mango tree cut section of trunk 
 The timber is of light pale colour but with patchy irregular grains. The open ends of fibres show dark colour. Fresh mango timbers contain lots of moisture and sawn pieces if not properly held for storing and seasoning, have a tendency to warp. Constituent resins make it difficult to saw and plane the timer. Dry timber is very stable and durable. Mango is considered durable to perishable, but also susceptible to moisture, fungal and insect attack.

Mango timber grains
 Mango wood is easily available, and was fairly cheap. It has been truly a country wood used only for rural or farm implements. The wide trunk allows timbers for shelves, door planks, school bench tops, seats, and chair handles. Mango wood cannot have clear polish, mainly due to the irregular grains. Mango wood is used for wood stair and ladder steps when Ironwood or Sadad is not easily available.
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