Teak

Site factors

Teak grows well in alluvial soils, fairly moist, warm, tropical climate with pH ranges from 6.5 to 7.5. Teak show ed poor growth and form on dry sandy soil, shallow or hard pan soil, acidic, laterite, black cotton and water logged soils. It is a light demanding species relatively high light intensity , i.e. between 75 and 100% of sunlight for better growth and development. It occurs from sea level to an altitude of about 1200 m with 800-2500 mm rainfall regime and also grows in  very moist areas with the annual rainfall of over 3,500 mm. Teak also grows in dry areas of Tamil Nadu, Rajasthan, Madhya Pradesh, Andhra Pradesh and Maharashtra. In the Indian Peninsula, teak experiences maxim um temperatures up to 48^oC and minimum about 2^oC in the dry zone of Central India while in the moist parts of the Southern India (west coast), the maximum and minimum temperatures of teak distribution ranges fr om 43^oC and 13^oC respectively.

Planting stock

Generally stumps or seedlings are used as planting material. For stump preparation, the seedlings have to be maintained in the nursery for about one year. Then the seedlings are uprooted, all the leaves and and secondary roots are removed and stumps (4 to 6 cm shoot with 15 to 20 cm tap root portion) were prepared. Stump planting is generally preferred and it is easy for transport. For seedling plantation, young seedlings are shifted to 2 polythene bags containing soil mixture and maintained in the nursery for 3 to 6 months.

Seed collection, processing and Nursery techniques

Generally teak starts flowering 6 years after planting, but profuse flowering occurs after 15 years. Flowering occurs from June to September and fruits can be collected from November to January. Though teak produces profuse flowering the fruit set was very poor (1 to 2%), probably the coincidence south w est monsoon with flowering which affects pollination.

Germination of teak is often poor due to dormancy. Pre - treatment of the seeds by alternate wetting and drying of the seed for a w eek is required to break the dormancy before sowing . The seeds were kept in a gunny bag and dock the bag in water , preferably in a running stream, for 12 hours, then spread the seed in the sunlight to dry for 12 hours. This has to be repeated for one w eek. Further grading of fruits according to size help in improving germination. Germination increases with increase in size of fruits .The germination percentage varies from 30 to 50 % in moist teak and 5 to 10 % in dry teak. The seeds were sown in the raised nursery beds (10 x 1 x 0.3 m) prepared with soil and sand mixture. The nursery beds have to be watered regularly and covered with coconut leaf or paddy straw. Germination starts 10 to 15 days after sowing and continues up to 35 to 45 days . The paddy straw may be removed once the seed started germinating . The seedlings can be transplanted to polythene bags or it can be maintained in the nursery beds for 10 to 12 months for preparation of stumps.

Plantation management

A suitable land with good soil and rainfall of > 1200 mm ma y be selected for raising teak plantation. The land should be ploughed thoroughly and prepare pits ( 45 x 45 x 45 cm) in 2 x 2 m or 3 x 3 m or 3 x 4 m spacing before rainy season. Farm yard manure with soil mixture has to be prepared and filled in the pits. Seedlings are planted in the pits during rainy season. For stump planting crowbar may be used and pitting is not required. In the initial stage the plants have to be watered weekly, and regular weeding and pruning have to be done . The branches have to be removed periodically without affecting the main stem. Drip irrigation is beneficial in farm lands . Irrigation reduce the rotation period and also enhance the productivity . Application of 50 g of urea and 30 g of super phosphate after six months and 75 g of urea and 60 g of super phosphate after 24 months of planting increases the growth rates. The fertilizers are effective for enhancement of growth in young teak trees than mature trees. Thinning (removing alternate rows) is done 5 years and 10 years after planting in plantation raised with closer spacing (2 x 2m). Mechanical thinning is also needed. The interval of thinning cycle is at age of 5, 10, 15, 20 and 30 for 60 year rotation, in Kerala. Teak can also be planted in bunds in south and north direction in such way the agricultural crops get sufficient light. It was found that there w as no significant variation in wood properties of young (25 to 30 years old) and mature teak (50 to 60 years old). Therefore teak plantation raised with good quality planting material or clones in good soil with limited irrigation and dry period with silivicultural practices can be harvested within 20 to 25 years. In Brazil and Malaysia teak is harvested at the age of 15 to 20 years. The teak growing in the canal areas in Thanjavur and Tiruvarur (Tamil Nadu) showed fast growth with good girth (> 150 cm) within 20 years and canal teak is harvested at the age of 30 years.

Agroforestry practices

Teak is one of the favoured silvicultural species by the farmers. It is planted in different models, combinations as well as in different spacements. IFGTB has developed agroforestry models like, Agri-silvicultural models (Teak + casuarinas with agricultural crops maize, cotton, turmeric, tomato and chilly), Agri-silvi-horticulture model (Teak + coconut with agricultural crops plantain, turmeric , vegetables, maize and cotton) and Silvi-horticulture model (Teak-Gauva, Annona) (George, 2000). Under irrigated lands, silvipasture model was developed with Teak and Casuarina as tree component and Napier and Guinea as pasture components.

Yield

The average productivity of teak in Nilambur teak plantations was 2.85 m³ ha ^-1 year ^-1 in 53 years rotation period. In Indonesia the MAI at the harvest age (40 to 90 years) w as 2.91 m ³ ha ^-1 y ear ^-1 (FAO, 1986). The productivity in moist semi deciduous forest in Ghana was 8-10 m ³ ha ^{- 1} y ear ^-1 (Oteng-Amoako and Sarfo, 2005) while in Central America it was 8 to 12 m ³ ha ^-1 year ^-1 (Arias , 2005). Recent studies conducted on teak growing in farmlands with irrigation, fertilizer application and management revealed the possibility of reducing the rotation period to 25 y ear s with increase in productivity. The trees grow in farm lands grow f aster and produce more biomass when compared to plantations in the forest areas. The quality of teak timber in farmland at 12 years was found to be similar to that of 20 years in forest land.

Important insect pest and diseases

Teak defoliator , Hyblaea puera and leaf skeletonizer , Eutectona machaeralis are considered to be the major pests in teak. These insects are known to occur on seedlings in nurseries and also in grown up trees in plantations . H. puera feeds on tender foliages during the early part of the growth season and E. machaeralis feeds on older foliage towards the end of the season. Making regular pest surveillance in nurseries and young plantations, particularly during rainy season when there is a new flush formation to detect the occurrence of the pest and removal and destruction of larvae if the population is less. If the pest attack is severe it can be controlled by spraying of the foliage with the chemicals like monocrotophos or endosulfan 0.05-0.075% or neem based formulations (Neemazal 1%) at 10-12 days intervals can give good control. A virus (NPV) based formulation (biocide) is also available for management of the defoliator H. puera.

Uses

It has been extensively used for decking , deck houses , rails , bulwarks , hatches , weather doors and planking . The traders and timber users recognized several varieties of teak suitable for different end uses. The huge teak trees from Western Ghats region (high rainfall range) are used for structural needs like ship and boat building , construction and bridge building . Teak from Central Indian region is known for colour, texture and grains preferred for furniture and aesthetic needs. Teak wood of Godavari valley in Andhra Pradesh is used for furniture and cabinet making for its ornamental figuring. Teak wood markets and depots are available in all teak growing states in India.

Source: Transfer of Tree Cultivation Technologies to Krishi Vigyan Kendras - Publication by Institute of Forest Genetics and Tree Breeding,Coimbatore.