Site Quality Improvement in Forest Management

Abstract of a presentation conducted by

Kushani Perera

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

The productivity of a site for tree growth is usually evaluated on a stand basis. Considered in this way, site quality expresses the average productivity of a designated land area for growing forest trees. A common way of expressing relative site quality is to set up from three to five classes, or ordinal ranks, such as site I, II and III. The characteristics of each class must be defined to enable any area to be classified.

Site is a complex of physical and biological factors of an area that determine what forest or other vegetation it may carry. Sites get degraded due to many reasons, especially due to human induced problems such as land clearance, clear cutting and deforestation, agricultural depletion of soil nutrients through poor farming practices, livestock including overgrazing, dumping of non-degradable trash, plastics etc.

Site quality is a measure of relative productive capacity of a site for a particular species.Different site gives different growth response to different species. Site quality can be influenced by climatic factors, topographic factors, soil edaphic factors and competition. Monitoring site quality is important to match the species with the site, to estimate the quantity (harvest prediction) and the quality of the timber, to monitor overall ecosystem productivity, diversity and resilience and to check the habitat type and quality.

Site quality can be evaluated by both direct (actual crop production) and indirect factors (plant indicators, crop statistics, site factors).The quality of the original site can be improved by using several silvicultural practices like fertilization, improving the quality of soil by using cover crops, mulches and mechanical methods such as plouging, harrowing and deep ripping of the soil to improve aeration and at the same time mixing the organic matter content of the soil.