FORMATH
Online ISSN : 2188-5729
ISSN-L : 2188-5729
Original Article
A Comparative Analysis of A Stochastic Control Model based on Mean-Reverting Process for Forest Stand Management
Atsushi Yoshimoto
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JOURNAL FREE ACCESS

2006 Volume 5 Pages 85-104

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Abstract

A stochastic model for log price dynamics was provided with use of a variant of mean-reverting process, in which the drift term was a linear function of price and the volatility term was a function of price as in that of geometric Brownian motion. By approximating this stochastic model by the binomial process, we constructed a stochastic control model for forest stand management. The proposed control model was to select an optimal decision from three controls, "Harvest-Plantation", "Harvest-Abandon", and "Wait for Harvesting" under price stochasticity. The forest stand growth was derived from the stand density management diagram in the Kyushu region, following the standard forestry practice manual. Using the monthly time series data of sugi (Cryptomeria japonica) log price from 1975 to 2000, our analyses showed that the proposed mean-reverting process outperformed geometric Brownian motion most based on AIC for the time series data from September of 1980 to April of 1991. The resultant reverted mean became around 26,000 Yen/m3. As for the corresponding optimal rotation age, it was showed that if the current log price was lower than the resultant reverted mean, the rotation was postponed forever due to the large degree of expectation of price increase over time. On the other hand, if the current price was above the reverted mean, the rotation age became longer as the current price approached to the reverted mean.

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© 2006 The Author(s) CC-BY 4.0

This article is licensed under a Creative Commons [Attribution 4.0 International] license.
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