For expansion of forest area by implementing thinning, it is important to analyze attitudes of forest owners, who are the ultimate decision makers for implementation of silvicultural practices in private forests.Using a questionnaire survey, we aimed to clarify the preferences of forest owners for the implementation of thinning practices. We surveyed the attitudes of forest owners regarding silvicultural practices and strategies to expand plantation forest area through commercial thinning.We conducted a questionnaire survey in Hayakawa, Japan, which has a large forest area, to examine forest owner attitudes about implementing precommercial thinning, commercial thinning from below, line thinning, or joint thinning together with other land owners. We also asked forest owners what criteria are important in making decisions for joint implementation of thinning. The interest of forest owners in line thinning was relatively low. Given a harvesting income to expenditure ratio that is not negative, more than half of surveyed forest owners, except for those with no intention to thin, intended to implement thinning. The most important factor for forest owners on whether to agree to joint implementation of thinning was the possibility of reducing harvesting costs by scaling up. If we could provide evidence that harvesting income and expenditure would not be negative when cooperating with other forest owners in joint implementation of thinning, it may be possible to expand managed plantation forest area under thinning with the forest owners’ consent.

In order to continue maintaining of cultural and historically valuable buildings, it is necessary to consider stocking of large sized and high quality timber. However, it is difficult to secure the timber for repair in Japan at present because the stock of the timber is assessed only by individual evaluation criteria. In order to maintain wooden cultural buildings, it is important to standardize the evaluation criteria. Purpose of this paper is to investigate individual evaluation criteria to selecting logs and in order to produce a timber required to maintain wooden structures. Moreover, it is intended to propose a criterion to selecting standing trees. For that purpose, we have selected logs at the timber market and have measured the size of their sapwood. The average sapwood width was calculated in order to predict a required size of a sawn timber. Then we measured the tree height and the diameter at breast height and upper parts of standing Japanese cypress trees growing at natural forests in Kiso area and using a three-order equation we have calculated their height curve and a relative taper-curve. Finally, we standardized the necessary size of the logs and the necessary size of the standing trees. As a result, we can now predict the size of standing trees as well as the size of the logs which are required to produce the wooden material quested to maintain historical wooden structures in Japan.

Effects of terrain and geographical condition on operational efficiency in silvicultural operations were examined and subsequently the operational efficiency was standardized depending on the single operations using the data of silvicultural operations from 1978 to 2005 in University Forest in Chiba, the University of Tokyo, Japan. No significant relationship was found between terrain and geographical condition and operational efficiency except the first thinning, which would require more labor for the site at <20◦ of slope than at >20◦. Variance of each operation was increased with decreasing workload, namely number of trees or area operated. The standardized operational efficiency showed the improvement or laborsaving of silvicultural operations in the experimental forest compared to the former one.

In the 21st century, the business activities using Internet have been starting in various circles. For forest regions, the advantageous characteristics of Internet such as “Transcendence of the distance”, ”Transcendence of time”, and ”Unrestricted volume of information” bring profits that were not obtained before. From these viewpoints, arrangement of the Internet usage is considered in this paper concerning three functions expected for the forest, namely wood production, sightseeing business, and offering of various environment. In other industrial circles, the methods of WWW usage have been changing from the information sending medium to the interactive communication tool. While ”Environment tax” has been introduced recently in each prefecture, the Internet can be used for the operation of this system.

Characteristics for forest stands and single trees of sugi (Cryptomeria japonica D. Don) facing high risk of snow accretion damage, were examined based on the results of the investigation in Toyama. As a result, the damage risk was high in the low mountainous region in the west of Toyama Prefecture. The first reason was that there remained a lot of plantations of Bokasugi that was a weak cultivar to the snow damage. Because the temperature was comparatively high, it was the second reason that the adhered snow easily fell. The forest stands with the high damage risk had the characteristics that the average height/diameter ratio was large, the slope azimuth was located on the leeward side, and the slope form was concave. The wood trees with a high damage risk had the characteristics of the large height/diameter ratio, and the small Young’s modulus of the tree trunk.

The reporting status of international forest resources and forest products statistics were analyzed based on the Global Forest Resources Assessment 2005 of FAO (2006) and ForesSTAT of FAO (last updated Dec. 2006). Those data should be the basis of the global model that integrates forest resources and forest products market of the world. In the FRA2005, about 70% of the countries with forest area reported its growing stock and the change of it. The total area of forests in the countries reporting them accounts for a little less than 90 percent of the total forest area of the world. The total forest area of the countries with some estimates on the amount of industrial roundwood production in the ForesSTAT accounts for 99% of the world forest area. About half a number of the records on industrial roundwood production are based on the reports from its own country and the other half of the records are temporary estimates by FAO and other organizations. Most of the developed countries with substantial amount of production report its own production, and about 3/4 of the reported amount of production in the world is reported by its own country. On the contrary, majority of production in the developing countries are not reported from its own country but estimated by FAO. Those data can be bases for timber supply and demand estimates for the developed countries that constitute more than 70% of the global supply and demand of the forest products except woodfuels. However, the quality of forest resources and timber production data for the developing countries are unfortunately poor and it is difficult to estimate the change of timber supply and demand in those countries.

Economic studies of the timber price and the demand/supply structure after World War II had been conducted mainly by the following four researchers, Akai, Handa, Kishine and Nomura. In this report, we overview their research results as well as those of others afterwords. Our findings are as follows. (1) Akai analyzed the time trend based on the ascent or decent of timber price, and discussed the trend fluctuations from the change of demand and supply structure. (2) On the debate of price by Nomura and Handa, price of domestic timber demand and supply were estimated to be non-elastic with approximately 0.2–0.5, from Nomura, Kishine and the later studies like that of Nomura, although the estimation of the price elasticity differs for the target period, products and the derived supply and demand function. (3) In the period of the high economic growth rate, the price fluctuation was influenced remarkably by the shift factor of the demand and the imported timber as a substitute material replacing the domestic timber rather than as a complementary material. (4) It may not be able to describe the supply behavior of forest owner by the utility theory. A multiple-choice assumed profit maximization, that is, whether harvesting the fixed amount of timber (an available forest inventory) now or later with an expected price, may be more suitable for this purpose than a multiple-choice of money and the reservation demand (an available forest inventory), which assumed the utility maximization.

In this study, we develop a dynamic programming model for seeking the optimal thinning regime. Unlike previous studies, the growth model for Toyama prefecture can project diameter distribution over time. Therefore, our model seeks the optimal combination of thinning methods and thinning intensity in each planning period. We apply our dynamic programming model to sugi (Cryptomeria japonica) forest stands in Toyama prefecture.

We apply a logistic regression model to the data of snow damage occured in Oyabe city in 2004 in order to analyse the damage risk on sugi (Cryptomeria japonica) stand on the continuous basis. For specifying factors effecting the snow damage, we rely on the following three information criteria, 1) Akaike’s information criterion, 2) Baysian information criterion and 3) Bias-corrected Akaike’s information criterion for selecting appropriate ones. Our results are compared with those from the previous work with the use of the discrete regression tree model. Our experiments show that the ability to judge the degree of the snow damage risk is almost the same for both approaches according to a critical value by 50%. This implies that considering the amount of information on the risk as well as automatic specification of appropriate variables for the model, we can conclude that the proposed method is superior to the previous one.

This paper is intended to present models for describing the dynamics of actual wood volume damaged by the pine wilt disease. Applying the Kermack-McKendrick epidemic curve, we derived the simulation model and tested its applicability. However, the model is not able to explain the various situation by the structure as is. The model structure is reviewed in order to support the various situation and recognized necessity of the multiplexing of the model and the addition of the base. The new models that can express the situation more definitely are suggested.