Vegetation Structure of Ajlun Woodlands in Northern Jordan

Abstract

Woodland vegetation in the Ajlun mountains of Northern Jordan was investigated and surveyed to determine the influences of altitude and topography on patterns of vegetation structure. Three tree species (Quercus calliprinos Webb, Q. ithaburensis Decne, and Q. aegilps) and seven shrubs (Styrax officinalis L., Cistus creticus L., Cistus salviifolius L., Atriplex halimus L., Calycotome villosa (Poir.) Link, Retema raetam L., and Sarcopoterium spinosum (L.) Spach) dominate the woody vegetation in the study area. Higher plant densities were found on the lower altitudes of southwest-facing slopes than on the higher altitudes of northeast-facing slopes. Species segregation occurred on the basis of three main investigated factors: (1) Community ecological importance value complex of the species which combines the relative density, the relative coverage, and the relative frequency of the species; (2) altitudes above sea level; and (3) northeast and southwest slopes. Regeneration was negatively affected by consequently continuous reduction in species diversity and tree-size distribution.