Using interviews and satellite images, the relationship between tree cover in pastures and animal management and productivity was studied in 53 farms in the dry zone of the Pacific Coast of Costa Rica. Additionally, the effect of high (27% of the area), medium (14%) and low (7%) tree cover in pastures on animal performance of Brahman heifers was studied on one farm. Growth rate, species selection and diet quality were evaluated during both dry (February-May) and rainy (June-August) seasons. Sixty per-cent of the farms produced beef only, 20% were dual-purpose and 20% a mix of beef production with crop systems. Ninety percent of farms retain dispersed trees in the grazing areas and in living fences. Tree cover was 16% (range of 0 to 60%) and was associated positively with the frequency of weed control, resting period of pastures, availability of family labor, years of farmer's experience on the study farm and the existence of off-farm economic activities, but negatively with the area of natural forest and the animal stocking rate. Heifers grazing paddocks with high tree cover had a growth rate of 893 g animal-1 day-1 during the rainy season, 13-14% higher than under medium or low cover. This was associated with a greater selectivity of Brachiaria brizanrha and higher nutritional quality (>60% digestibility) under high tree cover. During the dry season, heifers under high tree cover lost less weight (93 g animal-1 day-1) than those under the medium cover (160 g animal-1 day-1) but losses were similar to those under low cover (104 g animal-1 day-1).