长白落叶松纸浆林木材材性及纸浆特性的研究

长白落叶松纸浆林木材材性及纸浆特性的研究王树力，吴济生，仲崇淇（黑龙江省林业科学研究所哈尔滨１５０００４０）关键词长白落叶松，纸浆林，材性分析，纸浆特性纸浆林培育过程中，生物量是所有培育者关心的问题，而纸浆材材性及纸浆特性也是十分重要的内容，它涉及到...     

基于GIS空间分析技术的人为干扰强度火险评价研究

区域森林火灾的人为干扰主要分为人为负干扰和人为正干扰。通过基于GIS的空间分析方法,对人为火源的危险程度和人为正干扰的影响进行了分析与评价,确定了人为负干扰火险指标为农事烧荒、农事炼山造林、上坟、旅游与基本活动,人为正干扰火险指标为投入人力和投入资金,并确定了指标权重、指标度量算法和评价模型,并在实验区进行了验证,以火险等级区划图的形式进行了结果评价。     

北京八达岭人工油松林地表枯死可燃物负荷量研究

地表枯死可燃物负荷量多少是森林火灾发生的基础。调查八达岭林场不同地形条件下油松林地表枯死可燃物和林分因子,取得42块样地资料;用线性相关分析法对各因子与地表枯死可燃物负荷量进行分析,平均树高、坡度和海拔与对应负荷量有显著线性关系;应用多元线性回归中的逐步回归剔除法,建立了估测模型,除平均胸径外,平均树高、密度、郁闭度、海拔、坡度被引入,经检验回归显著,该估测模型可用于其它油松林地表可燃物负荷量估测。     

湖南借母溪自然保护区两栖动物区系研究

报道了借母溪自然保护区两栖动物资源和区系特征的调查结果。已知有2目8科25种。广布种5种，古北界种1种，东洋界19种。进而进行区系分析和多样性分析。     

Comparison of the modified Weibull and Richards growth function for developing site index equations

A site index model based on the Weibull cumulative distribution function was fitted to three stem analysis data sets of black spruce (Picea mariana (Mill) BSP), white spruce (Picea glauca (Moench) Voss) and aspen (Populus tremuloides Michx.). The resulting equations were compared with those based on the modified Richards' (1959) biological growth function (Ek 1971; Payandeh 1977, 1978). The Weibull-type model performed as well as or better than the biological growth function for white spruce and aspen, respectively, but it performed less accurately in the case of black spruce. The Weibull-type model appears to behave better, i.e., it produces more realistic height growth patterns, than the Richards function upon extrapolation particularly at young ages.     

外界生态因子对油茶品质影响的研究

对21个地区58个油茶物种(或优良品种)进行了含油率、脂肪酸组成、碘值和粗蛋白质等化学品质的分析。通过选取14个不同地区的普通油茶(Camellia oleifera Abel)的品质与19个生态因子进行多元线性逐步回归分析,揭示了不饱和脂肪酸含量与纬度成明显的正相关;种仁蛋白质含量与8、9月份的降雨量呈负相关的趋势。品质之间的相关分析表明:不饱和脂肪酸含量与蛋白质含量存在明显的负相关关系;不同物种之间,其不饱和脂肪酸含量与果实的大小成负相关。     

林分平均胸径100倍圆法测定每公顷断面积的理论初探(之二)--误差分析与修正系数

通过对100Dg圆公式含义的分析,对影响林分断面积精度的2个主要因子:样地株数密度与林分平均胸径估测值进行了误差分析与探讨,提出了样地株数密度估计林分株数密度采用典型选样,林分平均胸径估测值采用目测法等相应解决办法。其中,当目测值有偏差时采用修正系数可使100Dg圆的可靠性进行了理论上的探讨。     

岷江干旱河谷几种乔木抗旱性研究

岷江上游干旱河谷地区是我国西部生态环境最恶劣的地区之一,也是我国最困难的造林地区之一。本试验以生理研究为基础,选择干旱河谷区造林地内具有相对较高成活率和保存率的针叶树种岷江柏(Cupressus chen-giana)、辐射松(Pinus radiata)和阔叶树种臭椿(Ailanthus altissima)、榆树(Ulmus pumilaL.)、刺槐(Robinia pseu-doacacia),分别采用主成分分析法和综合评价法对影响其抗旱性的主要生理指标和试验树种的抗旱性进行了分析研究。结果表明:①影响该地区试验树种抗旱性的主要生理指标为:可溶性糖含量、SOD活性、游离脯氨酸含量、水分饱和亏缺度、叶片含水量和24h失水率;②5个试验树种的抗旱性表现为岷江柏最高,其次榆树>刺槐>臭椿,辐射松的抗旱性最差。     

Performance of forest groups in achieving multifunctional forestry in Flanders

The forest group is a new policy instrument in Flanders (northern Belgium) to realise multifunctional forest management. This group was introduced in 1995 and organises the various kinds of forest owners, private as well as public, on a local basis (mean working area 751 km²), with voluntary participation (as in all forest owner organisations). This study evaluates forest groups in Flanders through an analysis of their relevance, effectiveness, utility and implementation. The targets of forest groups are relevant to the evolving needs and priorities at the local, regional, national and international level. The effectiveness analysis reveals that most indicators — including the quantity of timber harvest, the number of members, the forest area with an accepted management plan, the area under management and the area with small-scale ecological measures — have been improving between 1995 and 2004. The utility analysis emphasises that the owners are motivated because the forest group provides information and increases knowledge, includes the owner into a collective management plan, offers a platform for sharing management experiences and acts as a union force against the government. However, the forest group is not the solution to introduce multifunctional forest management by all forest owners. The implementation analysis identifies a number of impeding factors, including the imbalance between rights and duties, inconsistencies between various policy aims, and failure of forest groups to act as a common forum for all stakeholders in their working area.     

Safety of the tram car for slopes examined by stress analysis of the ground structure

For monorail systems, it is very important to ensure the safety of the ground structure. We developed a tram car for slopes that utilizes the mechanism of the monorail and analyzed the stress of the ground structure that had double rails. First, we divided the ground structure into seven components, and formulated a procedure for calculating the stress of the ground structure. As a result, the stress that acts upon the main rail and the main rail connecting part was near the allowable stress, and each calculated value was within the allowable stress. We measured the stress by running the vehicle, and compared the measured values with the calculated values. As a result, some measured values were larger than the calculated values. However, the ratio of measured value to allowable stress was 90% or less. Finally, we calculated the static loading coefficient for each part, results of which were as follows: main and subrail: 1.1; rail connection part and prop foundation part: 1.0; rail installation part: 1.3. In the recalculations, it became clear that the recalculated values exceeded the allowable stresses. These results suggest that we need to review the ground structure materials.