GROWTH PERFORMANCE AND STAND STRUCTURE OF SOME ACACIA SPP. IN SOUTH WESTERN SAUDI ARABIA
Naturally growing Acacia spp. occur mostly as woodlots in some parts of Saudi Arabia. They are extremely important types of vegetation in a country with a very small vegetation cover and huge areas of deserts. The present study was carried out in five locations in Al Baha Region (semi-arid) in south western Saudi Arabia. The objective of the study was to assess the growth performance and stand structure of the natural cover of Acacia spp. in these locations. Such information is very essential for inference on the types of products that can be expected from forest utilization, it is central to growth and yield projection, and crucial for ecological assessment. Growth parameters measured were DBH (diameter at breast height, 1.3m), total height, basal area/ha, volume/ha, crown coverage relative to the total land area, stocking density and regeneration capacity. The results revealed that most of these species occurred as woodlots and few as forests. Generally, the stocking density and regeneration were low probably due to illicit felling for fuel wood and grazing. Tree heights were below the average perhaps due to the low stocking density and increased natural spacing between trees. Large trees were extremely rare; however the remaining stumps on the forest floor suggested that they were mostly felled down probably for fuel wood or construction purposes. Currently Acacia spp. in the study locations may provide very important environmental roles and non-wood products rather than provision of wood products. These forests and woodlots require immediate intervention and protection to attain sustainability.