CARBON STOCKS ASSESSMENT OF A SELECTIVELY LOGGED DIPTEROCARP FOREST AND WOOD PROCESSING MILL IN THE PHILIPPINES

Abstract

LASCO, R. D., MACDICKEN, K. G., PULHIN, F. B., GUILLERMO, I. Q., SALES, R. F. & CRUZ, R. V. O.
2006. Carbon stocks assessment of a selectively logged dipterocarp forest and wood processing mill in the
Philippines. This study determined effects of selective logging on carbon (C) stocks of a dipterocarp forest
in the Philippines. Biomass C was determined from fixed plots using a chronosequence of 1–21 years after
logging. The total C budget within an existing timber concession in the area, including that in the wood
processing mill, was analysed. Unlogged forests had mean C stocks of 258 Megagrams of C per hectare (Mg
C ha^–1), of which 34% was in soil organic carbon (SOC). About 98% of above-ground biomass C was in trees
≥ 19.5 cm diameter-at-breast height. After logging, aboveground C stocks declined by about 50% (100 Mg
C ha^–1). In between the cutting cycle of 35 years, logged forests sequester C at the rate of about 1.4 Mg C
ha^–1 year^–1. Before the next harvest, forests recovered about 70% of the original biomass C. Changes in SOC
showed no apparent relationship with the number of years after logging. About 40% of woody aboveground
biomass C was converted to lumber and veneer/plywood or sold as logs. Most of the remaining 60% was
emitted to the atmosphere as carbon dioxide through burning as fuel and decay.