Selection and Field Establishment of Tree Crops for Large Scale Plantations in Wet, Dry and Intermediate Zones of Sri Lanka

Rachitha Silva

Large-scale forest tree planting in Sri Lanka started in late 1950's and till December 1998 has covered about 140,000 ha of forest plantations belonging to the Forest Department. The main plantation species are Teak, Eucalypts (Eucalyptus grandis), and Mahogany etc. Most of the fuel wood, miscellaneous hardwood and teak plantations are located in the Dry zone. Eucalypts and Pine plantations are mostly in the up country Wet zone. Mahogany plantations are situated in Intermediate and Wet zone. Current emphasis is on indigenous hardwoods, like Nedun while planting of Pines is banned and Eucalypts is being planted only on a very limited scale.

The selection of a tree crop depends on; the purpose of intended plantation, the potential species available for planting, the site qualities, Silvicultural and economic factors. The purpose of plantation is a policy decision of Government arising from a domestic need. After determining the purpose, the choice of species is narrowed. If a native species meets the need, there is no reason to choose an exotic, if not exotics have to be introduced. Species and provenance trials have to be carried out before establishment of plantation. The site qualities play a major role in Genotype x Environment interactions. The site qualities like climate, soil, physiographic and biotic factors affect the growth at different sites. Silvicultural factors include silvicultural systems, ecological requirements of species etc. Economical factors include demand and supply, Relative costs and returns.

Field establishment of a selected species involve several steps like surveying, site preparation, planting, maintenance and tending operation. Field establishment techniques of several plant species for Dry and Intermediate zone (Teak, Mahogany), Up country (Eucalyptus microcorys) and Low country Wet zone (Nedun) have been discussed.