March 1996 until February 2000, an study about the phenology of the Tempisque tree [Sideroxylon capiri (A.DC.) Pittier] was made in the Tropical Dry Forest of the Barra Honda National Park (Costa Rica). Ten trees were choosen at random and their phenology was evaluated monthly during the first two years and every two months afterwards. Climatological data were also collected in situ. Trees change their foliage each year during the rainy season or at the beginning of the dry season. In contrast with other native species in forest, soil water deficit is not responsible for foliage change in S. capiri. Some elements that affect the process are photoperiod and herbivores. Unknown physiological mechanisms allow the tree to maintain foliage during the driest months (March and April). Flowering and fruiting may occur every year and in any season, but mostly in the dry season, with variability both among seasons and among individuals
Keywords: sideroxylon capiri, phenology, tropical dry forest, tempisque tree, barra honda national park