The effect of tree windbreaks/shelterbelts has been studies in Thal desert (Pakistan) on the yield of wheat crop in 1984 grown under irrigated conditions. Wheat was sampled in 1M2 plots along transect lines on the leeward side. The results obtained indicate a net gain in grain yield. There was also a loss of grain near the tree row which could be minimized by improved cultural practices and control of weeds. However, the economic gain from the sale of wood obtained from windbreaks more than compensated the loss.