Wild Olive Tree Mapping Extent, Distribution and Basic Attributes of Wild Olive Trees at Al-Baha Region, Saudi Arabia Using Remote Sensing Technology

This study provided detailed information on the extent and distribution of wild olive trees in the Al-Baha region according to tree crown size. The study area concentrated along the Sarah mountain, encompassing districts including Al-Qura, Al-Mandaq, Al-Baha, the southern part of Baljurashi and a small portion of Qelwa Mekhwa Al-Aqiq districts. This indicates that wild olive trees prefer to grow in high foggy mountain conditions, which was previously predetermined study as having medium to high vegetation density zones. The information extracted from high-resolution Pleiades satellite image revealed that, in the study area (1, 991 km2), there is a total of 717, 894 wild olive trees, of which 95, 990) 13.4 %) had large crown sizes (greater than 5.1m) ; out of the remaining, 228, 996 had medium (3.15.0m) and 392, 908 had small (less than 3.0m) crown sizes. The result showed that the districts of Al-Mandaq and Al-Baha have a higher density of wild olive trees with smaller crown sizes. On the other hand, Al-Qura and Al-Baljurashi have a lower density of wild olive trees with bigger crown sizes. Meanwhile, districts such as Al-Aqiq, Qelwa and Mekhwa have the least dense wild olive trees with smaller crown sizes. Further analysis of the images through automatic measurement of the tree crown diameter revealed that most of these trees (54.7 %) belong to a small diameter class (less than 3.0m), whereas big diameter class (greater than 5.1m) were observed to a greater extent at both Al-Qura and Baljurashi districts. This information would be essential in identifying the landscape preference of wild olive in the Al-Baha region.