Existing Status of Acacia Woodlands in Central Saudi Arabia: A Case Study in Hawtat Bani Tamim and Al Duwadmi

摘要

Acacia woodlands are ecologically important and it is necessary to understand its structures and dynamics to develop sustainable conservation strategies. This study aimed to provide baseline information on the composition and growth of Acacia woodlands in the Hawtat Bani Tamim and Al Duwadmi regions of central Saudi Arabia. Height, diameter at breast height, crown diameter, seedling density, and soil seed bank content of Acacia tree species were characterized for 27 remote, circular, 0.1-ha plots in both study areas. At Hawtat Bani Tamim, Acacia raddiana, A. tortilis, and A. ehrenbergiana accounted for 45.53, 37.5 and 16.96% of all species present there. Most DBH were in the 6–10 cm class. A. raddiana was the main species in most diameter classes. Most trees were 4.1–5.0 m tall and A. raddiana predominated in this height class. Acacia ehrenbergiana had 92.63% damaged seeds. At Al Duwadmi, A. raddiana represented 78.99% of all Acacia trees there. A. gerrardii and A. tortilis accounted for 11.93 and 9.07% of the species there, respectively. Most of the DBH values were in the 6–10 cm and 11–15 cm classes, and A. tortilis and A. raddiana were abundant in both classes. Most trees were in the 4.1–5 m height class, which was dominated by A. raddiana. A. ehrenbergiana had 88.26% damaged seeds. In both areas, there was a gradual decline in the number of trees in DBH classes > 35 cm. The Acacia species in the two areas showed a fair regeneration status. There were more seedlings than saplings and fewer saplings than trees. This baseline study could contribute towards future sustainability planning initiatives after other assessment studies have been conducted to identify changes in the Acacia woodlands of this region.