PREDICTING PRODUCTIVITY OF NATURAL PINES GROWN AT BAN WAT CHAN ROYAL PROJECT, CHIANGMAI

Abstract

An estimation of volume and biomass production of native pines naturally grown at Ban Wat Chan Royal Project of Chiangmai province was carried out financially supported by the Forest Development Administration of VACRS, Taiwan ROC, through the Royal Project and the Highland Agriculture Project of Kasetsart University. The study site is about 1,000 m above mean sea level with 2,545-mm mean annual rainfall. On the basis of dominant species, three sub-types of forest could be distinguished as follows: (1) Pinus merkusii stand, (2) Pinus kesiya stand, and (3) mixed stand of P. kesiya and P. merkusii. Twenty temporary plots of 10x10 m² in size were systematically sampled in each stand for data collection. Tree height was predicted from a simple regression equation developed having dbh as dependent variables. In a manner similar to total height, total biomass as well as biomasses of stem, branches, and leaves were estimated from allometric relation equations established from 10-sample trees harvested.

Both volume and biomass of P. merkusii stand were found to be greater than those of P. kesiya stand, followed by mixed stand. Such volume figures were of 198 m³/ha for P. merkusii stand, 194 m³/ha for P. kesiya stand and 121 m³/ha for mixed stand. Total aboveground biomasses of P. merkusii, P. kesiya, and mixed stands were of 165.87, 142.02 and 94.80 t/ha, respectively, while their stem biomasses were of 143.24, 121.55, and 82.47 t/ha equivalent to 86.42, 86.19, and 85.99% of total biomass, respectively. Productivity of P. merkusii in mixed stand both in terms of biomass and volume was found to be 3 times higher than that of P. kesiya.