Optimal stochastic control modeling for sustainable agricultural and forest resource management and optimal landscape management

本研究的目的是分析在不确定环境下的农业和森林资源的可持续管理，从经济的角度来看，朝着最佳的景观管理。研究从两个方面进行。一种是数学建模方法，另一种是基于调查的方法。本研究的主要内容如下：1.建立了一个寻求维持林分经营的最低阈值价格线的随机控制模型。分析表明，最低阈值价格水平受目标林分生长量的影响.提出了一种求解扩散过程的非参数方法。该方法具有以下优点：1避免了局部或全局估计多项式函数的所有系数; 2不需要核函数和与之相关的带宽选择; 3可以容易地进行感兴趣状态的预测、滤波和平滑.对原木价格动态进行了时间序列分析。结果表明，近10月出现了一个季节性降水高峰。原木价格的季节性程度大于木材价格.进行了杉干材生产的可行性研究。研究表明，要实现可持续生产，不仅要建立高效的生产体系，而且要建立多样化的产品体系.在听证调查的基础上，对森林所有者的经营方式进行了分类。管理风格被分为1。享乐型经营，业主通过森林经营享受和进行沟通;收入导向型管理; 3.大型资产控股管理;放弃管理，即所有者停止林业做法。

The objective of this research was to analyze the sustainable management of agricultural and forest resources under uncertain environments from the economic point of view toward the optimal landscape management. The research was conducted from two approaches. One is a mathematical modeling approach and the other is a survey based approach. The overview of the research is as follows ;1. A stochastic control model was constructed for seeking a minimum threshold price line to maintain forest stand management. Our analysis shows that a minimum threshold price level is affectejd by the target forest stand growth.2. A nonparametric method for diffusion processes was proposed. The proposed approach has the following merits : 1 avoid estimating all the coefficients of a polynomial function locally or globally, 2 : no kernel functions and no bandwidth selection associated with them were required, and 3 : prediction, filtering, and smoothing of states of interest can be easily conducted.3. Time series analysis was conducted on log price dynamics. The results showed that a peak of seasonaliry appeared in October recently. It was also shown that the degree of seasonality was severer for log price than lumber price.4. A feasibility study was conducted on sugi dried lumber production. It was shown that in order to seek the sustainable production not only an efficient production system but also a wide variety of products should be constructed.5. Classification of forest owners' management styles has been analyzed based on the hearing survey. The management style was shown to be categorized into 1. the pleasure-seeking management, by which the owners enjoy and perform communication through forest management, 2. the income-priented management, 3. the large-scale asset holding management, and 4. the abandoning management, where the owners cease forestry practices.