Tree resources decline in Saudi Arabia: Climate change or pest attack causes?

Abstract

In Saudi Arabia, tree mortality has abnormally increased over the past ten years, exceeding regulatory standards without clear interpretation. The present study aimed to investigate three attacked tree populations in different biogeographic regions of Saudi Arabia. For this purpose, climatic data from the last thirty years, forest densities, soil cover, pest search, and insect damage to trees have been reported. The results of this study show a distinct climate change manifested by an increase of 2 °C in temperature accompanied by a decrease in precipitation and the extension of drought periods during the last 30 years. Analysis of satellite images and the computation by quadrat methods revealed a decline in forest density and soil tree cover caused by dieback associated with an increase in the rate of tree pest attacks. Furthermore, tree investigations show attacks of the xylophagous beetles Steraspis speciosa and Paropta paradoxus on Acacia population in the north and centre of the country. In addition, many strains of termites are attacking the Dobera glabra population in the south of the Kingdom. This study shows that tree dieback, as a response to long periods of drought, when associated with pest attacks, provokes a dramatic decline in forest tree heritage. Climate change is the principal precursor to forest decline and pest invasion in Saudi Arabia.

Keywords

• climate analysis
• forest decline
• tree death
• xylophagous insects