The phenology of 160 individuals from 12 tree species of Costa Rica's montane forests were observed monthIy during 49 months, in order to evaluate the following phenophases: flowering, fructification and leafing (budding and falling). Different occurrence patterns were found for each evento Thus, flowering occurred continuously for one species bu! suh-annually for another. Four species showed annual flowering and the olher six supra-annual flowering. Flowering was concentrated from November 10 May, at the end of Ihe rainy season, and during ¡he dry season. Fructification was continuous for tbree species, annual for Iwo, and supra-annual for the other seven. There was more fruits production at Ihe end of the dry season and during the first months of the rainy season. New leaf production was a very dynamic event and highly synchronic for all evaluated species, showing annual rhythms for six of them. Leaf falling was a continuous event throughout the year, without abrupt changes for all species under evaluation.
Keywords: cleyera, drimys, magnolia, montane tropical forest, ocorea, phenological pattems, quercus, schejjlera, styrax, vaccinium, weinmannia