General Description
Teak (Tectona grandis) is a tropical hardwood tree species placed in the flowering plant family Lamiaceae. Tectona grandis is a large, deciduous tree that occurs in mixed hardwood forests. It has small, fragrant white flowers and large papery leaves that are often hairy on the lower surface. It is sometimes known as the “Burmese teak”. Teak wood has a leather-like smell when it is freshly milled. It is particularly valued for its durability and water resistance, and is used for boat building, exterior construction, veneer, furniture, carving, turnings, and other small wood projects. Tectona grandis is native to south and southeast Asia, mainly India, Sri Lanka, Indonesia, Malaysia, Thailand, Myanmar and Bangladesh but is naturalised and cultivated in many countries in Africa and the Caribbean. Myanmar’s teak forests account for nearly half of the world’s naturally occurring teak. Molecular studies show that there are two centres of genetic origin of teak; one in India and the other in Myanmar and Laos. “CP teak” (“Central Province” teak) is a description of teak from the central states of India. “Nagpur teak” is another regional Indian teak. It produces small, white flowers arranged in dense clusters (panicles) at the end of the branches. Flowers contain both types of reproductive organs (perfect flowers)The word teak comes from Tamil tekku , Malayalam thekku via the Portuguese teca. The plant is known in Sinhala as Thekka among the Sri Lankan people and Segun in Bangladesh.
Cultivation
Teak’s natural oils make it useful in exposed locations, and make the timber termite and pest resistant. Teak is durable even when not treated with oil or varnish. Timber cut from old teak trees was once believed to be more durable and harder than plantation grown teak. Studies have shown that plantation teak performs on par with old-growth teak in erosion rate, dimensional stability, warping, and surface checking, but is more susceptible to color change from UV exposure. The vast majority of commercially harvested teak is grown on teak plantations found in Indonesia and controlled by Perum Perhutani (a state owned forest enterprise) that manages the country’s forests. The primary use of teak harvested in Indonesia is in the production of outdoor teak furniture for export. Nilambur n Kerala, India is also a major producer of Teak of fine quality, holds the world’s oldest Teak plantation. Teak consumption raises a number of environmental concerns, such as the disappearance of rare old-growth teak. However, its popularity has led to growth in sustainable plantation teak production throughout the seasonally dry tropics in forestry plantations. The Forest Stewardship Council offers certification of sustainably grown and harvested teak products. Propagation of teak via tissue culture for plantation purposes is commercially viable. Teak plantations were widely established in Equatorial Africa during the Colonial era. These timber resources, as well as the oil reserves, are at the heart of the current (2014) South Sudanese conflict. Much of the world’s teak is exported by Indonesia and Myanmar. There is also a rapidly growing plantation grown market in Central America (Costa Rica) and South America. With a depletion of remaining natural hectares of teak forests, a growth in plantations in Latin America is expected to rise. Hyblaea puera, commonly known as the teak defoliator, is a moth native to southeast Asia. It is a teak pest whose caterpillar feeds on teak and other species of trees common in the region of southeast Asia.
Uses
Teak’s high oil content, high tensile strength and tight grain make it particularly suitable where weather resistance is desired. It is used in the manufacture of outdoor furniture and boat decks. It is also used for cutting boards, indoor flooring, countertops and as a veneer for indoor furnishings. Although easily worked, it can cause severe blunting on edged tools because of the presence of silica in the wood. Over time teak can weather to a silvery-grey finish, especially when exposed to sunlight. Teak is used extensively in India to make doors and window frames, furniture, and columns and beams in old type houses. It is resistant to termite attacks and damage caused by other insects. Mature teak fetches a very good price. It is grown extensively by forest departments of different states in forest areas.Leaves of the teak wood tree are used in making Pellakai gatti (jackfruit dumpling), where batter is poured into a teak leaf and is steamed. This type of usage is found in the coastal district of Udupi in the Tulunadu region in South India. The leaves are also used in gudeg, a dish of young jackfruit made in Central Java, Indonesia, and give the dish its dark brown color.Teak is used as a food plant by the larvae of moths of the genus Endoclita including E. aroura, E. chalybeatus, E. damor, E. gmelina, E. malabaricus, E. sericeus and E. signifer and other Lepidoptera including Turnip Moth.
Uses in boatbuilding
Teak has been used as a boatbuilding material for over 2000 years (it was found in an archaeological dig in Berenice Panchrysos, a port on the Indian Roman trade). In addition to relatively high strength, teak is also highly resistant to rot, fungi and mildew. In addition, teak has a relatively low shrinkage ratio, which makes it excellent for applications where it undergoes periodic changes in moisture. Teak has the unusual properties of being both an excellent structural timber for framing, planking, etc., while at the same time being easily worked, unlike some other similar woods such as purpleheart, and finished to a high degree. For this reason, it is also prized for the trim work on boat interiors. Due to the oily nature of the wood, care must be taken to properly prepare the wood before gluing. When used on boats, teak is also very flexible in the finishes that may be applied. One option is to use no finish at all, in which case the wood will naturally weather to a pleasing silver-grey. The wood may also be oiled with a finishing agent such as linseed or tung oil. This results in a pleasant, somewhat dull finish. Finally, teak may also be varnished for a deep, lustrous glow. Teak is also used extensively in boat decks, as it is extremely durable and requires very little maintenance. The teak tends to wear in to the softer ‘summer’ growth bands first, forming a natural ‘non-slip’ surface. Any sanding is therefore only damaging. Use of modern cleaning compounds, oils or preservatives will shorten the life of the teak, as it contains natural teak-oil a very small distance below the white surface. Wooden boat experts will only wash the teak with salt water, and re-caulk when needed. This cleans the deck, and prevents it from drying out and the wood shrinking. The salt helps it absorb and retain moisture, and prevents any mildew and algal growth. Over-maintenance, such as cleaning teak with harsh chemicals, can shorten its usable lifespan as decking.