Site preparation and forest plantation establishment in different geographical zones

Abstract of a Presentation conducted by

Gayan Udugama

Department of Forestry and Environmental Science, 

University of Sri Jayewardenepura, Sri Lanka

A written scheme of management aiming at continuity of policy and action and controlling the treatment is known as a Forest Management Plan. Under any plantations establishment survey and demarcation, site preparation, planting, irrigation, weeding, fertilizing, pruning, thinning, and regeneration felling are the main steps to be followed.

Survey and demarcation of boundaries is carried out generally using chain and compass survey or modernly using GPS technology. Before moving towards site preparation and planting operations, the buffer zones are identified and forest management layout will be prepared which includes location and shape of the forest plantation, road network plan, location of waterways, subdivision for fire breaks, access, spacing and mapping.

Site preparation is done to create favorable growing conditions for seeds and seedlings, and to facilitate tree planting operations. This will reduce the competition of unwanted vegetation in order to increase the survival and growth rate of the desired trees, remove slash and logging debris if the site has been harvested, and to improve water retention and provide optimal soil conditions to desired plants. The decisions taken here will depend on several factors such as existing vegetative cover, site terrain, purpose of plantation, species to be planted, soil conditions and economics.

In Sri lanka, abandoned chena lands/ vegetable lands, shrub lands and rubber uprooted lands are the common lands available for establishing forest plantation. Further such lands can be divided into three categories based on the geographic nature. They are namely flat areas, slopes and ridges. Therefore site preparation and planting operation will differ with the terrain. Generally in high slope areas forest plantation establishment is not carried out as the land is vulnerable to erosion and the operations are costly. Final decisions on the site preparation and planting will rely on the economics.

Vegetation clearance is the first step in site preparation where manual, mechanical, burning and chemical methods are used. In slopes and ridges mostly manual methods are preferred but in flat terrain mechanical and manual methods are being used. Burning is not allowed if the plantation need to be certified. Ploughing, subsoiling, pre-planting harrowing, planting pits and terracing is carried out after the vegetation is cleared.

Spacing of plantation will depend on objective of the planter and basically on several factors such as species, thinning operations, whether it’s an intercrop or a monoculture, etc. In slopes and ridges planting is carried out along the contours as a protective measure where in flat terrain any conventional planting layout suitable for land can be used.

Protection measures need to be undertaken for fire risk, pest and disease risk and for the risk of soil erosion and landslides.