TREE PATTERNS IN THE SUDAN

Summary Bands of acacia trees rhythmically disposed occur in the Sudan in a form resembling grass patterns. They have been found only on the red sand belt of Western Sudan, and aerial and ground observations and measurements seem to indicate that they all lie on gentle slopes very roughly on the contour, that they are as much as zoo m. wide with similar or wider spaces between them usually occupied by ground patchily covered by grass. Though sometimes tree bands may have a man‐made origin, the cause is generally natural and is probably the same as that producing grass patterns.