Production Function of Planted Mangroves in Thanh Phu Nature Reserve, Mekong Delta, Vietnam

摘要

Through assessment of forest structure, biomass of mangrove plantations in the Thanh Phu Nature Reserve, Mekong Delta, Vietnam was analyzed in correlation with diameter at breast height (DBH, i.e. at 1.3 m height). Study plots were set up in 7, 11-22, and 26-year-old planted Rhizophora apiculata Blume plantations. There is a significant inverse correlation between DBH and tree density (R-2 = 0.73; p < 0.01). To derive an allometric relation to estimate aboveground biomass, 32 trees representing all ages were chosen randomly and harvested at ground level to examine allometric relations. We measured the fresh and dry weight of stems (W-S), branches (W-B), leaves (W-L), and aboveground stilt roots (W-R) in situ. Allometric relationships were satisfied best with DBH as an independent variable (R-2 = 0.72, 0.89, 0.87, 0.98, and 0.97 for leaves, branches, stilt roots, stem, and total aboveground biomass, respectively; p < 0.001). The total aboveground biomass was estimated in the plantations to vary between 76 and 320 tons/ha. Of this, more than 50% of total aboveground biomass was represented by stems. The estimated biomass value of this study is consistent with that of other mangroves in the world. Total biomass of R. apiculata plantation in Thanh Phu Nature Reserve accounted for about 170,057 tons dry weight or 8056 tons C.