CONTRIBUTORS - WOOD WORKS
The global teak resource is therefore likely to expand , provided that appropriate cultural treatments , effective protection and management systems are applied to both the natural teak forests and the plantations on a long term sustainable basis .
Teak wood is dark golden yellow , turning dark brown upon prolonged exposure to air . Irregular figuring of darker streaks or marks , is quite common . The wood has a distinct leathery smell , but no appreciable taste . It is not lustrous . When first cut , the wood has an oily to sticky feel to it . Teak is used in shipbuilding ( decking and interiors ), exterior joinery , decking , veneer and plywood for panelling in homes and offices . It is in demand as a furniture wood . It is resistant to chemicals and is used for products exposed to acids . It is also used for boxes , chests , carvings and wood turning .
THE PROPERTIES OF THIS OUTSTANDING TIMBER ARE SUMMARISED BELOW FOR THE WOOD ENTHUSIAST :
TEAK : HARD FACTS
Botanical / scientific name :
Tectona grandis L . f . Family : Lamiaceae – the Mint family
Trade name :
Teak Other names : Burmese , Indian , Rangoon , Moulmein and Java teak ; Kyun ( Myanmar ), Giati ( Vietnam );
Origin : Myanmar , India , Peninsular Malaysia , Cambodia , Laos , Thailand and Java .
Conservation status :
Bole characteristics :
Teak is not CITES-listed and its conservation status has not been evaluated .
Tree size is variable , affected by site , soil and climate . The tree usually grows to 39 to 45m in height with a diameter of 1.2 to 1.5m . Trees in Myanmar can reach diameters of 1.8 to 2.4m .
May sak ( Laos ); Djati , Jati ( The Netherlands ); Teck ( France ); Teca ( Spain )
It is grown in commercial plantations in many countries , mainly tropical Africa and tropical America .
However , it is increasingly rare in its natural range , due to exploitation .
The length of the clean bole can vary from 6m to 27m . Trees that produce saw timber of these dimensions are usually 70 to 90 years old .
Colour :
Grain pattern :
Density ( at 12 % moisture content ):
Strength / bending properties :
Seasoning :
Durability and preservative treatment :
Working and finishing properties :
The heartwood is dark golden yellow , often with darker markings , turning dark brown to black on exposure .
Straight to an occasional wavy grain , displaying mottled figuring .
Timber from natural stands : Average 673kg / m 3 ( Ref 1 ) 480 ( 600-719 ) 839 ( Ref 2 ) 630 ( 650-680 ) 750kg / m 3 ( Ref 3 ) 560-800kg / m 3 ( Ref 4 )
Teak has excellent strength properties , making the timber suitable for a wide range of structural uses . It has medium to high crushing strength , low to medium bending strength ( MOR – Modulus of Rupture ), very low to low bending stiffness ( MOE – Modulus of Elasticity ), very low to low toughness ,
The wood seasons well , but rather slowly with very little shrinkage .
Teak heartwood has outstanding natural durability , a feature which has long been appreciated in the shipbuilding industry . It contains an oil that makes the wood very resistant ( but not immune ) to termite and marine borer attack .
The wood works very well , but is hard on tools . Very sharp cutting edges are essential during processing . Morticing and drilling operations can be done cleanly .
The narrow white to greyish sapwood is clearly demarcated from the heartwood and approximately 30mm wide .
The texture is moderately coarse to coarse and uneven .
Timber from plantations : 720-730kg / m 3 – 13 to 15 year old plantation trees in Costa Rica ( Ref 3 )
its Janka side grain hardness classification is ‘ soft ’ and its shear parallel to the grain classification is ‘ low to medium ’.
Both air- and kiln-drying can be done with no or very slight drying defects and once dry , the timber is remarkably stable in use .
It is resistant to fungal attack . The sapwood is susceptible to infestation by powder-post beetle . The heartwood is extremely resistant and the sapwood moderately resistant to preservative treatment .
The wood has good nailing and screwing properties and varnishes , stains and polishes well . Gluing results are best on freshly machined or sawn surfaces as the oily nature of aged surfaces may present problems in bonding .
// FEB / MARCH 2017 63