The practice of growing trees with agricultural crops has been often criticized on the grounds that trees cast shade, compete with farm crops for water and nutrients, attract birds which eat grains, serve as alternate hosts for insect pests, and impede the flow of water when trees are planted too close to water channels. To answer some of these questions two experiments were performed one at Pakistan Forest Institute and the other at Aslam Model Farm, Mirpur Khas, Sind. At Peshawar Dalbergia sissoo (shisham), Eucalyptus citriodora, Populus deltoides and Salmalia malabarica (Semal) were planted in 4 replications with 444m, size plot and trees planted at 4.3 x 4.3. m spacing with Pavan wheat variety. The yield of wheat varied 1700 kg/ha to 2762 kg/ha and no tree species had any significant effect on it. The Aslam Model Farm experiment included the planting of Eycalyptus camaldulenis over the area of 1000 x 630 m long. Each belt was 630 m. long and comprised 3 rows of trees spaced 2 meters apart. Trees in rows were planted at one meter spacing. Distance from the tree belt had no significant effect on yield of either grain or straw.