Atributos poblacionales y reproductivos de Pinus chiapensis en Chiapas, México

Abstract

THE EXPANSION OF THE AGRICULTURAL FRONTIER, TOGETHER WITH A MORE INTENSIVE HARVESTING OF FUELWOOD AND TIMBER HAS REDUCED AND ISOLATED THE POPULATIONS OF PINUS CHIAPENSOS IN THE MOUNTAINS OF TSOUTHERN MEXICO. THIS STUDY WAS AIMED AT PROVIDING INFORMATION ABOUT POPULATION STRUCTURE, SEED PRODUCTION, SEED GERMINATION AND SEEDLING SURVIVORSHIP OF THIS SPECIES IN REMNANT FOREST FRAGMENTS IN THE CENTRAL AND NORTHERM HIGHLANDS OF CHIAPAS. THE NUMBER OF SEEDINGS AND JUVENILES, AND REPRODUCTIVE CAPACITY OF ADULT TREES (NUMBER OF CONES/TREES, AND NUMBER OF SEEDS/CONE) IN FOUR LOCATIONS WERE ESTIMATED. GERMINATION WAS EVALUATED UNDER NATURAL CONDITIONS IN AN EXPERIMENTAL GARDEN (UNDER PINE CANOPY VS. IN THE OPEN) LOCATED IN SAN CRISTOBAL DE LAS CASAS, AND IN THE LABORATORY. GERMINATION WAS SIGNIFICANTLY DIFFERENT (P<0.001) BETWEEN THESE CONDITIONS, AS WELL AS AMONG SEED PROVENANCES (P<0.003), BEING HIGHER AND FASTER IN THE OPEN THAN UNDER THE PINE CANOPY. THE PROVENANCES SHOWED DIFFERENCES IN THE PROPORTION (P<0.001) AND NUMBER OF FULL SEEDS PER CONE (P<0.005). THE RESULTS SUGGEST THAT THE RECRUITMENT OF P. CHIAPENSIS SEEDLINGS MAY DEPEND ON THE AVAILABILITY OF GAPS IN CANOPY, AND SHOW EVIDENCE OF SOME GENETIC DIFFERENTIATION AMONG THE STUDIED DEMES.