Development and Application of an Algorithm to Calculate Cross-cutting Patterns to Maximize Stumpage Price based on Timber Market and Stand Conditions : A Case Study of Sugi Plantations in Gunma Prefecture, Japan

Abstract

We developed a cross-cutting pattern algorithm to maximize the stumpage price of each diameter class of timber, depending on market prices, and applied it to Sugi (Cryptomeria japonica) plantations in Gunma Prefecture, Japan. We used a relative-taper curve and a relative height-diameter curve to estimate taper by diameter at breast height class. Using this algorithm, we estimated the optimum cross-cutting pattern method based on Sugi log prices at different points in time. The optimum cross-cutting pattern allows the stumpage price to rise more dramatically than by the fluctuation of log prices alone. During 6 months, which is a relatively short period of time when considering market conditions, an obvious difference in optimum cross-cutting pattern was confirmed; in some cases, a focus on 3.65-m logs was beneficial, whereas in other cases, 4-m logs produced greater benefits. The difference accords with the prospective cross-cutting pattern considered profitable by the Gunma Forest Association. This result indicates that the algorithm can estimate optimum cross-cutting patterns according to changes in the timber market without contradicting empirical rules.