Potential of Ecosystem Phosphorus Storage in Ban Nong Tao Community Forests, Mae Wang District, Chiang Mai Province

Abstract

The potential of forest ecosystems on phosphorus storage was studied in Ban Nong Tao community forest, Mae Wang district, Chiang Mai province. The forests were divided into conservation (CF) and utilization (UF) forests. By using a method of plant community analysis, fifty sampling plots of 40 x 40 m were set up in each site, totally 100 plots, by a stratified random technique. Stem girth at 1.3 m above ground and height of all tree species with ≥1.5 m height were measured. Plant species diversity, biomass and ecosystem phosphorus storages were investigated. Totally 244 tree species (166 genus, 73 families) existed in CF. The family of Fagaceae had the highest species richness, whereas UF consisted of the lower number (132 species in 93 genus, 53 families). Pinus kesiya was the most dominated species in both forests. Species diversity index by Shannon-Wiener equation in CF and UF were 6.19 and 4.16, respectively. In CF, the most important species was P. kesiya while that in UF was Quercus brandisiana. Forest biomass was higher in CF (252.36 Mg ha-¹) than in UF (139.74 Mg ha-¹), and stored phosphorus amounts were 134.89 and 74.03 kg ha-¹, respectively. Average available phosphorus amounts in soils within 2 m depths in CF and UF were 73.44±19.71 and 23.02±4.09 kg ha-¹, respectively. The total ecosystem phosphorus storages in CF and UF were in the order of 208.33 and 97.05 kg ha-1. Differences in original plant communities and utilization by selective tree cutting resulted in lower plant species diversity, biomass and phosphorus storage in UF as compared to CF.