DIFERENCIAS EN LA PRODUCCIóN DE FRUTOS DEL ROBLE Quercus Humboldtii Bonpl. EN DOS BOSQUES ANDINOS DE LA CORDILLERA ORIENTAL COLOMBIANA

knowledge of mechanisms of tree species reproduction under natural situations including fruit and seed production patterns is very important for forest management strategies. considering the influence of abiotic factors such as soil characteris tics, humidity and rainfall on fruiting phenology, we studied fruit production patterns of the andean oak (quercus humboldtii: fagaceae) in two forest sites of the colombian eastern cordillera (cachalú and patios altos), under contrasting environmental conditions. at both sites, we monitored monthly fruit production of 15 trees in cachalú and 11 in patios altos using fruit/seed traps placed under the tree crowns. in each site soil cores were extracted below the litter layer 20 cm depth, and soil characteristics and nutrients were analyzed. in general, trees in cachalú produced more fruits than in patios altos, as well as mean fruit mass (wet and dry weight) was significantly higher in cachalú. at both sites, oak fruiting peaked from april to may, when the highest rainfall occurs. we found positive correlations between fruit production and rainfall one month prior. high phosphorus (p) and potassium (k) were the main variables for explaining the high production. in contrast, high aluminum (al) contents explained the low production found in patios altos. we discuss the importance of including fruit production for oak management strategies, such as restoration and reforestation programs.