ECOLOGY

Tectona Grandis is a large deciduous tree with a rounded crown and, under favorable conditions, a tall clean cylindrical bole of more than 25 m. The base of the tree is often buttressed (having outgrowths at the base caused by exaggerated root swelling) and sometimes fluted (having irregular involutions and swellings in the bole). Leaves are broadly elliptical or obovate and usually 30 to 60 cm long. Over most of its range, teak occurs in moist and dry deciduous forests below 1 000 m elevation and is one of the several species constituting mixed forest stands. It grows best in localities with annual rainfall of 1,250 to 3,750 mm, minimum temperature of 13º to 17ºC and maximum temperature of 39º to 43ºC. Hotter and wetter conditions also promote growth of the species.

Natural teak forests mainly grow on hilly and undulating terrain with traps, basalt, granite, schist, gneiss, limestone and sandstone as underlying rocks. The best teak forests, both natural and plantation forests, grow in well-drained deep alluvium with a PH between 6.5 and 7.5. It has been determined that a high calcium content has positive effects. Teak plantations have failed completely when they have been established on low-lying, poorly drained land with clay soils (Seth and Yadav, 1959). In the natural forests of Myanmar, teak grows mainly on hilly and undulating terrain and is one of several species constituting mixed stands.

Teak is a light-demanding species; it does not tolerate shade or suppression at any stage of its life and requires unimpeded overhead light for its proper development. Teak coppices and pollards vigorously and sometimes retains its coppicing potential even after attaining large size. Teak begins flowering and seeding at a young age, about 20 years from seedling and about ten years from coppice, and produces abundant seeds almost every year (Seth and Kaul, 1978). The hard thick pericarp of the seed prevents easy germination and a considerable portion of fresh seeds remains dormant in the first year. Teak seeds remain viable for many years.