Modelling cork oak production in Portugal

The layout of 32 permanent plots in the most important cork production regions of Portugal and the measurement of the most representative tree parameters were performed for statistically sound cork weight modelling. The establishment of cork weight equations is presented for the different cork oak study areas considered alone or grouped according to the most representative tree parameters. For the presented cork weight models was chosen independent variable the total stripping surface (artmax). For the selection criteria five statistic were used, including PRESS, APRESS and Mallows's statistic. The crossvalidation of the best classified models was performed and to discuss the importance of the “study area” factor, a regression analysis with “dummy” variables was performed.     

自然植被净第一性生产力模型及其应用

本文利用中国１２５组天然成熟森林资料及Ｅｆｉｍｏｖａ在ＩＢＰ期间获得的世界各地的２３组森林,草地及荒漠等自然被资料应用及相应的气候资料对目前流行的气候生产力模型;Ｍｉａｍｉ模型,Ｔｏｒｎｔｈｗａｉｔｅ Ｍｅｍｏｒｉａｌ 模型,Ｃｈｉｕｋｇｏ模型,综合模型及北京模型的适用性进行了研究。结果表明：Ｃｈｉｋｕｇｏ模型,北京模型与综合模型都能较好地反应森林净第一性生产力状况,但对于干旱半干旱地区,模型与综     

中西部地区退耕还林还草模式探讨

在将我国退耕还林还草工程区划分为 2个大区 9个类型区的基础上 ,研究了每个大区的退耕还林还草基本技术思路和每个类型区的退耕还林还草模式 ,包括其类型区域范围、自然资源特点、社会经济特点、主要限制因子、基本技术思路、林草类型结构、植被恢复方式、植被恢复技术、主要树种草种、经营管护方式等     

基于时延神经网络的木材干燥模型辨识的研究

木材干燥是一个复杂、多变的过程，传统的系统辨识方法很难建立一个理想的木材干燥模型。利用时延神经网络的特点，本文提出了基于时延神经网络的木材干燥模型辨识方法，并给出了辨识网络和结构。对辨识得到模型的仿真结果表明，利用时延神经网络所建立的模型是可靠且有效的。     

Conducting surveys on forestry attitudes and practices in Leyte communities,Philippines: Experiences and lessons learnt

A survey of forestry practices and attitudes was undertaken in four communities in Leyte, the Philippines, to improve understanding of the social and economic factors affecting small-scale forestry development. The survey had three main data collection activities — initial focus group discussions (FGDs), household interviews, and reporting and validation FGDs. A team of enumerators was selected for household interviews which consisted of both males and females, to avoid potential problems of unwillingness of people to talk with those of the opposite gender. The interviewers were also required to be able to speak local dialects (Cebuano and Waray Waray), the survey questionnaires being administered in these dialects. Various methods were used to gain the support and assistance of local government units and barangay captains. Some difficulty was experienced by the survey team in the first community due to barangay elections at the time of the survey, and the requirement by the University of Queensland Ethics Committee that respondents sign a consent form. This requirement was found to be not culturally appropriate for the Leyte smallholder communities. Offering goods at the end of the interview was found to be of limited value for encouraging participation in the survey. Provision of food and drinks were found to encourage FGD participants to express their views, but too much alcohol had a negative effect. The importance of providing comprehensive feedback to respondents and involving them and other stakeholders in development of policy recommendations was apparent. These survey experiences provide valuable insights which are not generally available in textbooks on sample surveys, and provide lessons for planning and conducting smallholder community survey into natural resource management issues.     

中国木工机械制造业的国际竞争力探讨

首先阐述了我国木工机械制造业的发展现状,然后运用迈克尔.波特的钻石模型对我国木工机械制造业国际竞争力的影响因素进行了深入分析,最后提出提升我国木工机械制造业国际竞争力的几点建议。     

荒漠化程度评价高光谱遥感信息模型

本文用国产高光谱分辨率成像光谱仪系统数据对荒漠化评价建立定量化遥感信息模型。对荒漠化评价因子中的主要定量因子 (植被盖度、生物量和土壤含水率 )进行了定量反演 ;对难于进行定量计算的评价指标 ,先通过目视解译获得各因子的编码图 ,分别进行影像化后参加荒漠化程度评价遥感信息模型计算。通过每个像元都可获取全部评价因子的指标值 ,在现有的荒漠化评价方法的基础上 ,建立以像元为单位的荒漠化程度评价的定量化遥感信息模型并输出荒漠化程度分布图。结果表明 ,用高光谱数据定量反演荒漠化地区植被生物量、盖度和土壤含水率是比较可靠的。当反演区域内灌木和草地同时存在时多项式模型的精度要明显高于线性模型 ;当植被类型单一时 ,模型即为较高精度的线性模型 ,但模型的应用地域范围受到限制 ,只能分块进行计算。因此 ,在只有灌木和草地的区域用多项式模型反演会提高效率。土壤含水量的反演方法适合于地形平坦、植被比较稀疏的条件。但研究发现 ,基于土壤热惯量的含水量模型具有一定的抗植被干扰能力。荒漠化程度评价的遥感信息模型的精度主要取决于现有荒漠化评价的方法 (即评价指标是否科学合理、专家给定的权重和等级标准是否客观 )以及各指标数据的获取精度     

Growth and yield prediction models for Acacia mangium grown in the plantations of the central region of Bangladesh

Acacia mangium is a very fast growing species belonging to the family Leguminosae that has been introduced in the plantations in Bangladesh for its faster growth and wide range of adaptability. The present study aimed at development of growth and yield prediction models for the species using simultaneous equation method. Models were selected for the species to estimate stand dominant height, stand diameter, stand basal area per hectare and total volume yield per hectare. Paired t-test, 45-degree line test, percent absolute deviation and biological principle of stand development were used for the validation of chosen models. The results suggest that the models derived were statistically and biologically acceptable and could be satisfactorily used for stands of Acacia mangium of ages 4–7 yrs based on a base age of 6 yr.     

贮木场选址模型的研究

建立了一个贮木场选址的数学模型，这个模型将动态经济评价方法，运输网络和贮木场选址有机地结合起来。     

王朗林区人工缺苞箭竹亚层数量特征及其模型

王朗林区人工缺苞箭竹亚层数量特征及其模型刘兴良，向性明（四川省林业科学研究院成都６１００８１）关键词四川王朗，亚高山暗针叶林，亚建群层，缺苞箭竹，大熊猫，仿真造林缺苞箭竹（Ｆａｒｇｅｓｉａｄｅｎｕｄａｔａ）是四川王朗林区亚高山暗针叶林下亚建群层的主要...