PENYUSUNAN MODEL PENDUGA VOLUME POHON JENIS JELUTUNG RAWA (Dyera polyphylla (Miq) V. Steenis)

Abstract

The development ofDyera polyphylla trees requires complete information on the estimated yield. The estimated yield or volume can be obtained by using an estimating equation for the tree volume.The objectives was to obtain of the best estimation models for the total and merchantable volumes of D. polyphylla trees. The volume estimation models were formulated using 96 selected tree samples representing the whole stand populations. Sample trees were measured using Spiegel Relascop Bitterlich (SRB). The estimator models tested consist oflinear and non-linear models with a single variable (diameter) and double variables (diameter and height ofthe tree). The results ofthis study indicatedthat diameter as the single variable can be usedto formulate an estimatormodelfor both the totaland merchantable volumes of trees. However, the addition of the height variable into the model is still needed. The estimation models oftree volumes with two variables (diameters andheights) were used to obtain a standardvolume table. The determination coefficient rose less than 2% compared to the model with the diameter variable. The best model oftree volume estimators with either one or two variables has high coefficient (> 80%) ofdetermination (R ). 2 The best models ofestimating total tree volume are 1) with the use ofdiameter as a single variable: Ln Volume c c 7 9444 2.1952 Ln DiameterccD and 2) with the use ofdiameter and height as double variables: Volume . c c c c c * =2.4081*10 *(Diameter .Height) . The best models to estimate the volume ofmerchantable trees are 1) with the -4 2 0.80871 use ofdiameter variable: LnVolume=8 2598+(2.2843)*(Ln(Diameter)), and2) with the use ofdiameter andheight . as the variables: LnVolume=9.0589+(1.8958)*(Ln)Diameter))+(0.7347) *(Ln(Height) )