Great timber on our doorstep Teak, which produces high value tropical timber, can be grown successfully in northern Uganda BY WALTER MAPANDA
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eak (Tectona grandis) is recognised worldwide for its excellent wood properties, which make it suitable for a range of uses. The ancestral home of teak is Myanmar (formerly Burma), India, Thailand, Laos, Cambodia, Thailand and Vietnam. Unrestrained clearing of natural teak forest in Asia has led to teak plantation development outside Asia. As far back as 1858, teak plantations were shown to be economically feasible. The plantations were at the time located in countries of teak origin, especially Myanmar. In Africa, Nigeria was the first country to establish a teak plantation in 1902. It was followed by Ghana in 1905 then Ivory Coast in 1929. Teak has also been introduced in other West African countries such as Benin, Guinea, Senegal and Togo. In East Africa, teak is grown in Kenya, Sudan, Tanzania and Uganda. In places where optimum site-species matching is done for teak plantations, they are normally very profitable. If maintained properly, a hectare of teak can gross more than US$ 250,000 in 20 years. Generally, plantation establishment and maintenance costs are projected at approximately US$ 17,000 per hectare over 20 years (United Teak, 2007). Therefore, investment requirements for teak establishment and maintenance are generally low in relation to the revenue realised through thinnings and final harvest. However, teak requires more intensive silviculture than pine and eucalyptus and there are serious social, economic and environmental
considerations to take into account when proposing establishment of a teak plantation. Teak monoculture plantations are susceptible to defoliating pests, especially when undergrowth is suppressed and site conditions are not optimal. In addition, genetically superior planting stock is scarce and poor standards of post-planting care operations (slashing, chemical and manual weeding) have adversely affected the productivity of teak plantations in the world. In Uganda, information on teak site-species matching, establishment, fertiliser application, response to weeds, thinning and pruning is out-dated, scarce and scattered.
Precious wood Teak wood has unique properties. Its sapwood is pale yellow-brown to cream or ivory in colour, while the heartwood is a dark golden-yellow when fresh and turns to a dark golden-brown with exposure. With prolonged exposure to the weather, the colour lightens. The grain is generally straight and the texture is moderately coarse and uneven due to the presence of growth rings. When seasoned, teak weighs approximately a tonne per 1.5 cubic metres. Teak is a slow-growing tree so its timber is denser and heavier than that from other timber species. Density is approximately 670 kilogrammes per cubic metre at 12 per cent moisture content. Teak can be kiln-dried easily and its degradation is minimal. It also air-seasons very well and has little tendency to split or warp. Air seasoning of teak is slow but once seasoned, the timber is exceptionally stable and has a low co-efficient of expansion
and contraction under changes of atmospheric temperature and humidity. Teak is highly resistant to termites and marine borers. The wood has a distinct oily feel, which makes it water, acid and fire resistant. The durability of teak wood comes from a variety of natural reasons including high oil content and silica. The oily resins, called tectoquinones, naturally repel termites and resist rot. The silica content makes it difficult for marine borers to damage the timber. It is also resistant to decay when fully exposed to the weather, clear off the ground, with free air circulation. Despite having a high silica content and an oily feel when wet, the dry wood glues well. The timber works easily both with hand and machine tools and it takes both nails and screws fairly well.
Uses Teak has outstanding wood properties. As such, it is used for a number of construction functions including flooring, decking, deckhouses, rails, hatches, weather doors, planking, cladding, fasciae and bargeboards. It has decorative applications such as lining, panelling, turnery, carving, outdoor and indoor (cabinetwork, sleepers) furniture and parquetry. Teak is also highly priced as a boat and shipbuilding timber.
Silviculture of teak Traditionally, site quality for teak plantations is assessed by the top height of trees (average height of 100 largest dominant trees per hectare). Pandey 1966, cited in Panama Forestry, 2006,
Table 1: Site factors important for growing teak Altitude (m)
Drought
Rainfall (mm)
Temp ( OC)
Effective rooting depth (mm)
Less than 1000
Teak is very resistant
1250 to 3750
13 to 40
More than 800
Teak grows and develops well in low attitude, high rainfall areas and in climates that have a three to four months dry season with less than 60mm precipitation. The hotter and wetter the better. The species favours sites with very deep soils. Source: Kaosa-ard, 1981 cited in Panama Forestry. (2006)
Miti July - September 2013
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