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We examined the relationship between Dorcas gazelle and livestock use of trees according to size. Our data suggest that Dorcas gazelle use of trees differs according to species and size. larger Acacia trees are used for territorial purposes whereas smaller trees may be visited within the course of grazing. Our data show that tree size also determines potential food availability. On shorter trees, gazelles can graze on leafy vegetation at a range of heights between ground level until the top of the tree. In contrast, leafy vegetation on taller trees is available at heights that are often too high for gazelles to reach. However, larger trees provide another food source for gazelles not found on shorter trees such as seed pods, which were only found on larger Acacia radiana trees. There was no significant difference between the size of the other tree species that were used and not used by gazelles. Goats, camels, and donkeys were typically associated with only larger trees, regardless of species. Dorcas gazelle conservation will require maintaining viable Acacia populations that are characterized by recruitment and a variation of tree sizes and ages. (C) 2011 Elsevier Ltd. All rights reserved.