FORMATH
Online ISSN : 2188-5729
ISSN-L : 2188-5729
Volume 5
Showing 1-12 articles out of 12 articles from the selected issue
Original Article
  • -The Stand Density Control Diagram,Stand-aggregate, and Forest Management-
    M. Matsumoto, E. Izumi, M. Fujiwara
    Type: research-article
    2006 Volume 5 Pages 11-23
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    The objective of this study is to develop a model that makes a prediction about operational effects of an assumed management plan based on a real forest. In this study, forest was considered to be stand-aggregate. This prediction model of forest stand resources was constructed by using the system dynamics method; which enables us to analyze flows and stocks. In this prediction model, the forest-stock element was arranged according to ageclasses in order to express age-succession in the forest by applying the idea of stand density control diagram. Consequently, we could express management plans as the succession of stand density. The transitions of forest stand resources were estimated about private sugi (Cryptomeria japonica) forest of Kuma Town, Ehime Prefecture in terms of 100-year-cutting-period.

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  • Hirokazu Yamamoto
    Type: research-article
    2006 Volume 5 Pages 25-42
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    Timber-frame building is a symbol of Japan’s “Culture of wood” which makes use of renewable natural resources for construction. Compared to that of the West, Japan’s is fundamentally different in that it incorporates a unique recycling system of timbers. In the 21st century, we face the global issue of limited natural resources and in groping for a more suitable solution, it is to this Japanese tradition of timber-frame building that we should turn to in to guide us to an important future course so that not only Japan’s buildings but also its forests, with its rich natural reservoirs remain intact. Ninety percent of cultural buildings designated by Japanese government are made of wood of which nearly half have roofs made of materials derived from vegetation. Due to the perishable nature of these materials, traditional buildings tend to be affected by rain and wind. Therefore, scheduled maintenances and restorations of these buildings must be continued into the future. About 30-40 percent of building parts are commonly replaced and at times requiring complete dismantlement. In order to enforce a schedule of maintenances, it is important to keep stocks of wood for repairs and a system to obtain these stocks on a long-term basis is essential.

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  • -Illustrated Range of Sympathy-
    Hiroshi Tokimitsu
    Type: research-article
    2006 Volume 5 Pages 43-61
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    One sympathized with another which was similar to ego. The motion of one’s heart was affirmed and the promoting method was considered with figures. Hinoki (Chamaecyparis obtuse Endl.) stands were illustrated on a map with four fields. A stem changed to a triangle board by a rotary lather, and stems were collected to form a stand. Growth was realized as movement to an end. The bounds changed with time. The end was shown as a yield table, and target change was administration. Therefore growth was managed to the end. In order to affirm the management, the end expressed on the map could be realized and the administration should be affirmable.

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  • H. Yanagihara, A. Yoshimoto, Y. Ninomiya
    Type: research-article
    2006 Volume 5 Pages 63-83
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    In this paper, we presented a statistical procedure of estimating the clustered multivariate linear regression model for predicting the amount of carbon sequestered in a forest stand where there exist several growth patterns. The procedure is as follows: 1) By fitting a volume growth curve to the data of each sampled tree, parameters of the applied growth curve model are estimated. 2) By setting the estimated parameters as new observations, we classify growth patterns of sampled trees by k -means method based on the new observations. 3) We construct a multivariate normal linear regression model with dummy variables for k -clusters. 4) Among a set of the estimated regression models with the different number of clusters, the best model is selected by minimizing the resultant predictive Akaike’s information criterion (PAIC) for the remaining trees. 5) Finally, by using the best set of parameters of growth curves for the remaining trees, we predict the amount of carbon sequestered by remaining trees with its asymptotically 1−α confidence interval.

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  • Atsushi Yoshimoto
    Type: research-article
    2006 Volume 5 Pages 85-104
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    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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  • -Comparison between Four Universities-
    Mariko Tanaka
    Type: research-article
    2006 Volume 5 Pages 105-126
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    Searching for the strategy to increase the consumption of domestic timber, a questionnaire was enforced for university students. In this questionnaire, future trend for lumber use was investigated from 4 universities; Tokyo University of Agriculture, Shizuoka University, Takushoku University, and Tokyo Keizai University. In this report, results of questionnaire are analyzed from 475 answers. The questionnaire includes the items about the residence desired to live in the future life, favorite wood interior and furniture, building of school and public society house in tree, and the idea for the new wood product. Comparing the answer from students of the law and economics departments with that from students of agriculture department, it is revealed that former students have a tendency to dislike timber products than latter.

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  • K. Yukutake, K. Fukushima, I. Fujikake
    Type: research-article
    2006 Volume 5 Pages 127-141
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    As a result of timber imports including North American timber of the major species, the timber self-sufficiency rate in Japan is below 20%. Timber prices are depressed, and planted forests are being abandoned in the middle of the rotation without suitable silvicultural treatments, which means that the application of sustainable forest management becomes difficult. A rise in the supply of home-grown timber could, therefore, be closely linked to achieving sustainable forest management. We approached the feasibility of sustainable domestic forest management by examining the effects of North American timber imports on Japanese timber market using a demand/supply model. Among others, our estimates of the cross price elasticities of demand for Russian, New Zealand, and domestic timber for the price of North American timber, which has the largest share in the market, were 0.619, 2.603, 0.149, respectively. We also found that the 10 % increase of all of the housing starts, exchange rate and oil price in the US raised equilibrium consumption of domestic timber only by 1.0%.

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  • Naoto Matsumura
    Type: research-article
    2006 Volume 5 Pages 143-154
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    In that the interest in the sustainable forest management rises, the integration of objective forest resource information and the nationwide information service become important. Also, forest resource inventory is reconsidered as the basic information for the purpose of conservation of the forest environments and biodiversity, and mitigation of the global warming by, for example, the forest sink project. It was shown that the accumulation of the data and the cross-check are important especially after surveying and reviewing the characteristics of the previous forest inventory regarding the design of the multipurpose permanent monitoring system.

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  • - Result and Application -
    Masahide Aoyagi
    Type: research-article
    2006 Volume 5 Pages 155-166
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    The Oketo Experimental Forest (est. 1955) is situated within a prefectural forest in Oketo Town in eastern Hokkaido. In this forest, trees have been felled at eight-year intervals (management stages) and five management stages have been completed thus far. For all forest units, the diameter-tree curve (tree diameter vs. number of trees per hectare), on the semi-logarithmic graph with the diameter grade on the horizontal axis and the number of trees per hectare on the vertical axis (logarithmic values), was essentially a straight line (correlation coefficient≒1), confirming that the accurate estimation of stand volume from diameter-tree regression lines is possible. Since one regression line indicates the stand volume of one forest unit, the area between two lines represents the difference in volume between the two forest units (amount of trees felled). Based on this relationship, a simulation method that optimizes natural forest managements was developed.

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  • M. Takahashi, H. Taoda, M. Inagaki, K. Ishizuka
    Type: research-article
    2006 Volume 5 Pages 167-175
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    Japan was covered with a grid having a 20 km ~ 20 km mesh size, and an appropriate monitoring site was selected for each mesh (total 1000 sites). Thirty percent of the monitored stands had trees with some symptoms of decline or damage in the tree crown, primarily due to high tree density of the stand. Damage caused by severe climate conditions such as typhoons and heavy snow was the second leading cause. Insect damage and fungal deceases were found in 3% of all the stands. Unknown causes, which suggest forest decline from air pollution and acid rain, were responsible for less than 10% of the damage in all stands. The monitoring confirmed the absence of damage due to anthropogenic pollutants in Japanese forest areas.

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  • T. Hiroshima, Y. Zheng, M. Matsumoto
    Type: research-article
    2006 Volume 5 Pages 177-186
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    Purpose of this study was to evaluate the political implication on carbon sequestration in the forests and houses sectors. Forests and houses sub models were constructed and employed to conduct simulations that predicted the amount of carbon to be sequestered in planted forests and wooden and non-wooden houses on a national scale over 50 years planning horizon based on several policy scenarios. As a result, carbon uptake in the forest sector got decreased in all of the scenarios year by year. Carbon uptake in the house sector got decreased in first 20 years and increased after that.

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  • Nobuyuki Yamamoto
    Type: research-article
    2006 Volume 5 Pages 197-205
    Published: 2006
    Released: June 05, 2020
    JOURNALS FREE ACCESS

    Since mid-90s the study about forest resource accounting system has been developed in Japan. The forest resource accounting system is consistent and comprehensive system for representing forest resource and environmental information. It goes on the framework of SNA (System of National Accounts). We have various ways of understanding it. As one way, we understand forest resource accounts comprises the four accounts of (1) forest accounts, (2) forest land accounts, (3) forest product accounts, and (4) forest management accounts. This paper focuses on reconsidering the study about the forest resource accounting system and representing the importance of it for the forest management.

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