FORMATH
Online ISSN : 2188-5729
ISSN-L : 2188-5729
7 巻
選択された号の論文の11件中1~11を表示しています
Original Article
  • Nophea Sasaki, Banjamin Smith
    原稿種別: research-article
    2008 年 7 巻 p. 1-14
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    The role of forests in absorbing atmospheric carbon has been recognized under the Kyoto Protocol, which allows signatory countries to use forests as a mitigation option. Although several studies have estimated carbon stock changes in Japanese forests, most only estimate changes through 1995 or ignore carbon stock changes in natural forests. This study is the first attempt to estimate carbon stock changes in Japanese forests from 1966 to 2012, the final year of the Kyoto Protocol’s first commitment period. Forest land use and growing stock data were analyzed. Then, two models of forest land use change and growing stock were developed. Analytical results showed that most natural forest loss resulted from conversion to plantation forestland, while a minor portion was converted to other forms of land use. Carbon stock in Japanese forests increased from 857.3 TgC in 1966 to 1594.2 TgC in 2012, representing an increase of 16.0 TgC year-1 over the same period. During the first commitment period of the Kyoto Protocol, annual carbon sequestration was estimated at 15.3 TgC, of which about 77.1% was sequestered in plantation forests. Only carbon sequestration in specially managed forests is credited under the Marrakesh Accord; thus, eligible carbon is expected to be lower. When data of specially managed forests become available, further study of eligible carbon sequestration is necessary because it could provide a baseline for decision making about the use of carbon sinks for carbon emission mitigation.

  • Potential for Implementation of Afforestation and Reforestation CDM Projects
    Naoto Matsumura, Eiichiro Nakama, Taulana Sukandi, Rinaldi Imanuddin
    原稿種別: research-article
    2008 年 7 巻 p. 15-24
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    The Conference of the Parties 9 in Milano, Italy (COP 9, 2003) approved modalities and procedures for afforestation and reforestation (A/R) project activities under the Clean Development Mechanism (CDM) of the Kyoto Protocol. According to the conclusions of COP 9, several approaches are available to monitor temporary carbon sequestration in A/R-CDM projects. Developing baselines for such monitoring is difficult because of a lack of basic growth and management data. In this paper, we present guidelines for preparing a project design document (PDD), in which growth and yield prediction in plantation forests plays an important role, and present a methodology for modeling and estimating carbon stocks using inventory data from Acacia mangium plantations in Malaysia and Indonesia.

  • Yasushi Mitsuda, Shigejiro Yoshida
    原稿種別: research-article
    2008 年 7 巻 p. 25-37
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    We examined the usefulness of distance-dependent competition indices for predicting individual tree basal area growth in a mature Japanese larch plantation. Using data from a permanent sample plot, we calculated several traditional distance-dependent competition indices and constructed individual growth prediction models. Results of regression analyses suggested that tree size could explain a large part of variation in tree growth much better than distance-dependent competition indices. We also used local indicators of spatial association to detect “hot spots,” or clusters of similar-sized trees, and “cold spots,” or clusters of trees of varying sizes within sample plots. Relationships between basal area growth and diameter of trees in “hot spots” and “cold spots” were analyzed.

  • Hirokazu Yanagihara, Yoshiyuki Ninomiya, Atsushi Yoshimoto
    原稿種別: research-article
    2008 年 7 巻 p. 39-59
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    Even in the same even-aged forest stand, trees grow differently due to their own growth capacity, relative spatial conditions, and other environmental factors. In this paper, we use a Gaussian mixture model (GMM) to investigate growth patterns in an even-aged forest to identify groups of trees with the same growth characteristics. Given the Richards growth function for the growth process, the estimated coefficients are used as new response variables in a multivariate GMM to identify growth patterns. The optimal number of grouped growth patterns is searched by minimizing the cross-validation (CV) criterion. We demonstrate our proposed method using growth data from a sugi (Cryptomeria japonica) sample plot in Hoshino Village, Fukuoka Prefecture, Japan. The model identified three separate growth patterns in our sample plot.

  • Atsushi Yoshimoto
    原稿種別: research-article
    2008 年 7 巻 p. 61-77
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    Expectation of the future trend and volatility of log prices has an impact on forest management decisions under stochastic environments. In this paper, we investigate the reverted mean level of log price dynamics using several variants of the mean-reverting process. Market-based log price data in Fukuoka Prefecture, along with nationwide averages, are used for the analysis. Target timber products are 3 and 4 m sugi (Cryptomeria japonica) and hinoki (Chamercypress obtusa) dimensional log. Parameter estimation is carried out by a quasi-maximum likelihood method. Our analysis shows that the reverted mean price differs significantly between the nationwide average and market-based price dynamics. Because the nationwide average price data smoothes market-based price dynamics, the underlying volatility is underestimated when compared to market-based price data. The estimated parameter values of all models from the nationwide average price are also much smaller than the estimated parameters from the market-based models. The reverted mean derived from the market-based data tends to show a decreasing trend over the time horizon, while the nationwide data does not.

  • Sándor F. Tóth
    原稿種別: research-article
    2008 年 7 巻 p. 79-93
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    This study summarizes work that focused on quantifying the spatial tradeoffs behind conflicting forest management objectives. The term “spatial tradeoff” refers to the spatial consequences of different management objectives. The techniques build on spatially-explicit forest planning models and have the capability to identify Pareto-optimal harvest schedules with respect to various timber and non-timber objectives. The focus of this study is to demonstrate how tangible information on forest resource tradeoffs and production possibilities can be used to (1) identify efficient compromise management alternatives, (2) build consensus among stakeholders with conflicting interests, and (3) help realize and market environmental forest services.

  • Perspectives of Japanese Suppliers
    Toshiaki Owari, Yoshihide Sawanobori
    原稿種別: research-article
    2008 年 7 巻 p. 121-133
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    Japan grants the largest number of chain of custody certificates outside Europe and North America. Certified companies may receive market benefits from their own certification and certified products. In this study, we examined the benefits of chain of custody certification in the forest products market in Japan. A nationwide survey was conducted from October to December 2005 of 132 companies that had obtained a chain of custody certificate from one of the certifying bodies operating in Japan: the Forest Stewardship Council (FSC), the Programme for the Endorsement of Forest Certification schemes (PEFC), or the Sustainable Green Ecosystem Council (SGEC). In the mailed questionnaire, respondents were asked if they received any premium from their certified products. The perceived level of benefits gained from a chain of custody certification was also measured using a 5-point scale. Results indicated that it was not possible for most Japanese companies to receive premium prices for certified forest products. Factor analysis determined three benefit dimensions: (1) business performance, (2) customer relations, and (3) environmental communication. The mean benefit rating of environmental communication was the highest, followed by customer relations. Business performance was rated significantly lower than the other two dimensions. Paper products companies, as well as large companies (≥ 300 employees), received relatively high benefits from certification.

  • Yozaburo Ejiri
    原稿種別: research-article
    2008 年 7 巻 p. 135-159
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    This study uses three-dimensional diagrams to express the export function, total labor demand function of individual countries, and the world-market supply function, and describes a method to specify the trade equilibrium point. The trade model is constructed as a multi-commodity, multi-country general equilibrium model, but actual simulation is conducted by a twocountry, two-commodity model. The specific factors model is adopted when assuming the production function has a decreasing return to scale and only one variable (i.e., labor input), and wage is assumed to be an exogenous variable. First, the total labor demands of each country are derived as functions of the price of each good, and these total labor demand functions are expressed by three-dimensional diagrams. Second, the “price possibility frontier” domain for each country is defined by the total labor demand function and labor endowment. Next, the equilibrium trade point is specified by the “price possibility frontier” and the restriction on the balance of supply and demand of each good. Last, the normative equilibrium trade point is simulated, using actual data from the Japan–U.S. international input–output table for the year 2000. The simulated normative trade follows the same direction as actual trade. This result suggests the usefulness of this method for analyzing how the internalization of public benefits from forestry or agriculture impacts the pattern of international specialization.

  • Wil de Jong
    原稿種別: research-article
    2008 年 7 巻 p. 179-204
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    Forests and forestry were first seriously considered as a vehicle to reach development objectives in the 1970s, leading to the recognition of community forestry as a focal point for international development cooperation. The exact opportunities for cooperation, and how to realize them, have changed as international development thinking has evolved. In recent decades, traditional academic analyses of communal forestry and development practices have been complemented by trends that focus on specific aspects of forests and local people, including non-timber forest products, forest devolution, decentralization, and collaborative management. The perceived role of community forestry in development cooperation, as well as the type of assistance that is needed and provided, continues to evolve with changing international development agendas, priorities, and objectives.

  • Shourong Wu, Shigeyuki Miyabayashi
    原稿種別: research-article
    2008 年 7 巻 p. 205-221
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    This is a comparative study of environmental consciousness between China and Japan, mainly regarding forests. We used questionnaires to research environmental consciousness of urban and rural elementary school students in China and Japan. The research was conducted in underdeveloped Sichuan and developed Fujian Provinces of China, and in Tokyo and Gunma Prefectures of Japan. We introduced five aspects of environmental consciousness: environmental sensitivity, attitude, conduct, knowledge, and participation. We performed multiple comparison testing using nonparametric tests. Overall, the results indicated that Chinese students' environmental consciousness is higher than Japanese students, with highest levels in Sichuan Province, followed by Fujian Province and Japan. Rural Sichuan students scored highest in sensitivity, conduct, knowledge, and participation. Urban Sichuan students scored highest in attitude, followed by rural Sichuan students. Japanese students scored lowest in attitude, knowledge, and participation, but higher in conduct than Chinese students, except for rural Sichuan students. Fujian students ranked between Japan and Sichuan.

  • Róbert Marušák, Atsushi Yoshimoto
    原稿種別: research-article
    2008 年 7 巻 p. 223-237
    発行日: 2008年
    公開日: 2020/05/22
    ジャーナル フリー

    This paper examines the issue of forecasting growing stock development and cutting possibilities based on the actual regeneration period of individual forest stands. These cutting possibilities represent a harvest level that is sustainable in light of forest stand regeneration. A survey was conducted using two groups of forest stands taken from the Forest Management Plan database at the Training Forest Enterprise of the Technical University in Zvolen, Slovakia. We compare the growing stock and harvest levels estimated by considering the actural regeneration period with those estimated by the following indicators of allowable cut: analytical cutting percentage, empirical cutting percentage, 1/20 of standing volume of forest stands in the two oldest age-classes and older, and 1/30 of standing volume of forest stands in the three oldest age-classes and older. The results indicated that cutting possibilities estimated by considering the actual regeneration period can be used as the judging criterion for selecting the most suitable allowable indicator to the target forest management unit. For our experiments, the empirical cutting percentage outperformed the other indicators on the basis of suitability of the derived cutting possibilities.

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