Penyusunan tabel volume sortimen jati (Tectona grandis, L.f.) di kph Pemalang perum perhutani unit I Jawa Tengah

Abstract

Forest inventory is an activity related to tree stand potency prediction, including timber potency. As it is in Jati forest, the purpose of inventory is estimating the quality and quantity of timber potency. Table volume classification is needed to make tree volume prediction less complicated. There are one or more variables that usually used in tree table volume prediction. Because timber values are different in each sorts, Jati timber value is depend on its’ sorts type. Therefore, volume information of each sort type is absolutely required. Spread diagram from the sample tree were conducted to determine the models that will be used to predict the tree volume, whether it is linear (single and multiple) or non-linear. Based on the diagram, tree table volume prediction model can be determined. Tree volume prediction models, according to Spurr (1952), i.e: 1. Berkhout Model : V = a Db 2. Shumacher Hall Model : V = b0 Db1 Tb2 3. Stoate Model : V = b0 + b1 D2 + b3 D2 T + b4 T The Spurr models above can be transformed into linier regression models through the use of logarithmic transformation. Berkhout model type, which is often used in tree volume prediction, needed to be transformed into logarithmic equation. Conversely, Schumacher Hall and Stoate equation are already in linear type that logarithmic transformation is unneeded. Jati volume prediction at KPH Pemalang by using Berkhout model without transformation delivered better accuracy compare to another models with transformation. Best Jati volume prediction model determined at KPH Pemalang is Modified Geometric model : V = 13.432379 D (-29.5999/D). D in the equation determined as diameter breast height, within range 18-70 cm. Jati volume prediction per sort at KPH Pemalang can be determined based on the proportion of sort volume to total tree volume. The tree volume can be attained from model V = 13.432379 D^(-29.5999/D).