eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2015-04-28 12 1 219 230 5300 article Loutfy El-Juhany 1 Prince Sultan Institute for Environmental, Water and Desert Research, King Saud University, P.O. Box 2454 Riyadh 11451, Kingdom of Saudi Arabia The natural forests of Saudi Arabia occupied a large area in the mountainous southwestern region. This forest area is considered a unique ecosystem in Saudi Arabia representing a semiarid zone while the rest of the country lies within arid zone. The forests in Saudi Arabia have been important for human life in this region for a long time, where it was the main source of woods used for house constructions, cooking and warming. In addition, they are important habitats for wildlife and flora. Now, they are open as recreation centers and for tourism. These forests have been suffering from varying degrees and types of degradation due to both human-induced and natural factors. Juniperus procera trees in these forests have exhibited a widespread decline with extensive tree dieback and die-off. Dieback is a phenomenon affects different tree species overall the world. It occurred in the natural forests of Saudi Arabia since about 35 years. Now, vast tracts in these forests are seen full of trees affected by dieback and die-off. The causes of dieback have not been clarified yet. Many researchers have expected natural disturbances, such as drought, sand storms, fire, floods, insects and diseases, climate change that may lead to die-back and die-off. The magnitude of dieback of juniper trees vary from place to place and it existed in both lower and high areas. Indeed, it spreads overall the forest area in the southwestern Saudi Arabia. The percentage of juniper trees which are affected by dieback in Taif, Baha and Asir sub-region accounted for 5.1, 14.5 and 11.4, respectively. Solving this problem must base on information about its magnitude, effects, causes and then the way by which it can be eliminated. https://www.biotech-asia.org/vol12no1/the-magnitude-of-dieback-on-juniperus-procera-trees-in-the-natural-forests-in-the-southwestern-region-of-saudi-arabia/ Dieback; Juniperus procera; natural forests; Saudi Arabia