this present paper deals with the contribution of tree shading to reduction radiation heat load in poultry houses. typically dimensioned facilities, east-west and north-south-oriented, located at the southern latitudes of 0; 10; 20 and 30 degrees were considered. sheltering efficiency was expressed as an index in function of space and time. such index (isg) takes into account the shading effect of trees in and out the facility. use of tree shading was more efficient in the north and northeast regions of brazil, where the solar irradiation is higher than south and southeast regions. the east-west as well for the north-south orientations of the facilities the same was observed. an index of isg of 25% was observed in the northeast region for east-west oriented facilities, while a value of isg = 33% was observed for the north-south orientation. for all the latitudes shading effects were more efficient in the north-south orientation. the southeast index was isg = 21% for the east-west and isg = 32% for the north-south orientation.