This study examines the impact of bark gnawing by black rat, Rattus rattus, on lemon trees during spring 2019 in the region of Ouargla (North-east of Algerian Sahara). Bark gnawing was occurred in all parts of the tree (trunk, branches, and twigs), but it was not as fatal. Our results revealed that approximately 66% of the 400 trees were affected by gnawing. The intensity of damage trees varied from 7 % to 56%, with the highest proportion of gnawing occurred in the branches, followed by twigs and trunk. We anticipated that the black rats needed to gnaw the bark to supplement their food, although the reason for this behaviour remains uncertain; further research are needed to understand this behaviour and establish management strategies are necessary to protect orchards and reduce potential losses.