Establishment and maintenance plan for Dipterocarpus zeylanicus plantation

Establishment and maintenance plan for Dipterocarpus zeylanicus plantation

Abstract of a seminar presentation

Based on a hypothetically formed plantation company

Deshika Kariyakarawana

Dipterocarpus zeylanicus, commonly known as “Hora” in Sinhala is endemic to Sri Lanka. It is a large tree attaining a height of 40m and a girth of 4m with a dense hemispherical crown. This is an important and common species in the low land wet evergreen forest where it occurs generally scattered below 1000m altitude. In river banks and well-drained alluvium, the species grows often vigorously. In wet evergreen forests which is generally storied, the top canopy consists essentially of dipterocarps.

The species regenerates freely and the seedlings establish themselves without much difficulty. Flowering is in January to February and fruiting is during April to May. Sapwood is pinkish white and heart wood is dark reddish brown. Strong hard wood timber comes under class I. After preservative treatments it can be used for railway sleepers, rafters, electric posts, beams, joists, heavy carpentry work and eminently suitable for underwater and marine work. Bark contains oleo resins.

Management objective of the plantation company is to optimise the land utilization by growing commercially viable and environmentally sustainable trees to invest at present to make profit after 35 years.

Plants will be produced in an own nursery with a six months nursery period. Seeds can be bought by villagers. Initially 988 trees per hectare will be established in the land of 50 hectare with the spacing of 2.5m×2.5m. Fertilizing will be done once per year until the 10^th year and weeding will be done for all 35 years. Two thinning operations are scheduled at 10^th year and 25^th year. Pest or disease attacks are not recorded for the species recently in Sri Lanka but termites can be a problem. Watering will be done using drip irrigation using water from the river at the boundary of the plantation nursery.

After felling the trees at 35^th year, logs will be sectioned in to 5m pieces and loaded in to containers for transport. Transport will be done by the customer. Estimated no. of trees in final harvest is 37050 with the total income of Rs. 12,327,244,592 including income from thinning. With some assumptions made for maintenance cost changes and timber price changes, in 35 years, expected profit is Rs. 11 billion. The IRR value is 24% at the end of 35^th year.