Abstract: This thesis studies efficient protection distance and area of farmland protective forest in the comprehensive agricultural development area in Karamay. The results indicate that at present the program of windbreak is unreasonable. Under vested site condition, tree height which the windbreak can reach can not plays a role in protecting the farmland within the development when the windbreak becomes mature. In order to achieve efficient protection, increasing density of the main or subsidiary windbreak is feasible. The main and subsidiary windbreak’s space distance should be 270m and 400m respectively in common wind speed and medium site condition. At the same time, the area percentage of the efficient protection is 16.55%, 13.64%, 10.65%, 7.54%, 4.87%,2.59% and 1.12% respectively on the condition that the wind speed slows down 20%～50%.

Key words: Karamay, windbreak, efficient protection distance, efficient protection area