Allometric Biomass Equations, Biomass Expansion Factors and Root-to-shoot Ratios of Planted Acacia mangium Willd. Forests in West Java, Indonesia

Abstract

We present two models of log-linearequations for biomass estimation in planted staiids ef 3-to 1"year-old\rAcacia mangium Willd.trees,using destructive sampling dataof 59 trees inWest Java,Indonesia.The log-linear\requations includeparameters for individualleaf,branch, stem, abeveground, belowground (rooO,and tutal\rbiemass.Average annual incrementsof stand-level biomasswere estimated at 7.77 to 1O.09tha''y'i(modelA) and at\r7.91to 10,27thai y'i (modelB), with the largestvalues inthe 5year-oldstand, Followingthe methodology\rpresentedby IPCC NationalGreenhouse Gas InventeriesProgramme, we calculated basicwood density(D),\rbiomass expansion factors(BEF),and root-to-shoot ratios (R)of the study stands.\r'Ihe\rvalue of D increased\rsignificantlyas stand age increasedfrem 3 to 8 years, but didnot significantly differbetween & and 10-year-old\rstands. The value of BEF didnot differamong the3-to&year-oldstands (average1.332) and decreasedte 1.180in\rthe 10-year-oldstand. The values ofR increaseclsignificantly with stand age, from O.157 to O,190.The BEF values of\rA. mangi"m inthis study were smaller thanthe defaultvalues forthetropica]broad-!eaf foresttype(dbh> 10cm)\rgiven by IPCC (mean,3.4;range, 2.0-9.0).Because many factors may affectthe parametervalues oi log-linear\requatiens and D, BEE and R forbiomass estimation, the equations and values providedinthis study are only\rapplicable to A. mangium forestsgrowing under comparable climatic, stand age, forest management conditions.\r