Vertical distribution and zonation pattern of woody vegetation on the northwestern slope of Mt. Mayon, Philippines

摘要

The study was conducted mainly to determine the plant diversity and zonation pattern of woody species on the northwestern slope of Mt. Mayon National Park, Bicol Peninsula, Southern Luzon, Philippines. Presently, the area is subjected to frequent volcanic eruptions and intensive anthropogenic activities such as fuelwood gathering, swidden farming and wild plant collecting. Point-centered quarter and quadrat methods were used to examine 15 sampling sites with elevations from 500 to 2200 m above sea level (m asl).A total of 71 species belonging to 49 genera and 33 families were identified from the three altitudinal vegetation zones determined by cluster and principal component analyses. Zone I is Erythrina-Ficus-Glochidion zone (500-800 in asl), Zone II is Astronia-Cyathea-Weinmannia zone (900-1500 m asl) while Zone III is Eurya-Clethra-Neonauclea-Fagraea-Vaccinium zone (1600-2200 in asl).Dipterocarps which normally characterize vegetation on the lower altitudes of tropical mountains were absent on the northwestern part of Mt. Mayon possibly due to unfavorable soil conditions brought about by frequent volcanic eruptions and the ever intensive human activities.