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.     

鲁中南山地刺槐萌生更新林经济效果评价

采用企业动态经济评价方法对刺槐萌生林不同轮伐期的经济效果进行了评价；按ＮＰＶ最大、ＩＲＲ最大确定了林分经济成熟龄；通过敏感性分析确定了经济成熟龄区间。     

四倍体刺槐、国槐和红叶石楠对根癌农杆菌菌株及不同抗生素敏感性研究

以含有RD29A目的基因和NPTⅡ筛选基因的根癌农杆菌菌株LBA4404、GV3101和EHA105侵染饲用型四倍体刺槐(Robinia pseudoacacia)、国槐(Sophora japonica L.)和红叶石楠(Davidson Photinia)的组培苗叶片,研究3个树种对根癌农杆菌菌株和不同抗生素(替门汀和头孢霉素)的敏感性、以及根癌农杆菌菌株对3个树种的侵染能力。结果表明,不同树种、不同根癌农杆菌株和不同抗生素种类均对转化效果产生明显影响,红叶石楠是最佳受体材料,3个菌株侵染后的平均抗性愈伤率为37.0%,其次为国槐,四倍体刺槐最低;根癌农杆菌菌株LBA4404侵染能力最强,3个树种的平均抗性愈伤率达到33.3%、平均分化率达到17.6%;替门汀对农杆菌侵染后的红叶石楠组培叶片抑菌效果最好。     

刺槐种群生物量动态研究

研究了河北省太行山刺槐种群乔木层生物量、各组分量及种群密度的动态规律。结果表明，刺槐种群自人工造林伊始，其种群总生物量、各组分量、种群密度（断面积表示）即表现出速增性，约至１２ａ生达到峰值，基本符合Ｌｏｇｉｓｔｉｃ规律。此后随个体间竞争的加剧，自疏作用加强，种群呈不稳定状态，种群密度和生物量下降，由一个同龄纯林逐渐趋向于具有多代个体年龄结构稳定的群体，并使种群生物量回复到一个相对稳定水平。本文还建立了生物量及各组分量与种群年龄、密度的相关模型，及Ｗ～ｆ（Ａ，Ｇ，Ｈ）多元线性回归议程。     

特种黑木炭研制报告

特种黑木炭是用柞、槲烧制的具有较高密度的木炭。影响黑木炭密度的主要因素有原料含水率和径级、干燥与炭化速度、炭窑窑形及精炼。本文还对烧制特种黑木炭过程中的具体操作技术要点进行了详尽的论述。     

微波加热软化木材的弯曲工艺研究

研究了微波加热水曲柳试件进行弯曲的工艺及其弯曲工艺参数与产品质量的关系。研究结果表明：该弯曲工艺可行;最佳工艺条件为木材含水率60％,微波加热功率400W,微波加热时间2.5min;该方法较传统生产方式的生产率明显提高。     

黑琥珀李株和冠幅与土壤养分相关的研究

应用逐步回归和通径分析，对土壤养分与黑琥珀李株产和冠幅增长的相关关系进行了研究，结果表明，土壤的机质，水解氮，速效磷和速效钾4个养分因子对黑琥珀李株产和冠幅的增长都有着显著和极显著的相关关系，其中以速效磷对产量和冠幅的增长作用最为显著，并且4种土壤养分因子之间存在着相互关联，互为作用的关系，因此，旋肥时应各种营养元素综合考虑，不能偏施。     

干旱地区提高刺槐造林质量的技术方法

中阳县地处干旱的黄土丘陵沟壑区，造林成活率低，成林难。该文在总结多年造林实践的基础上，从旱地育苗，提前整地，截干栽植，造林密度等方面，提出了提高刺槐造林质量的技术方法。     

黑银杏优良无性系选育研究

在对全县银杏种质资源普查的基础上，通过初选、复选和高接栽培对比试验，从２９７株雌银杏古树中发现并选育出了两个具有药用价值高、结实早、丰产稳产、抗逆性强等特点的黑银杏优良无性系———中银黑１号和中银黑２号。黑银杏种仁中总黄酮含量０９ｍｇ／ｋｇ，叶片中总黄酮含量８５ｇ／ｋｇ，分别比普通银杏高５０％和４１７％。文中还介绍了黑银杏的优良经济性状、生物学特性和生态学特性。     

Susceptibility of Eucalyptus grandis and Acacia mearnsii seedlings to five Phytophthora species common in South African plantations

Eucalyptus grandis and its hybrids, as well as Acacia mearnsii, are important non‐native trees commonly propagated for forestry purposes in South Africa. In this study, we conducted pathogenicity trials to assess the relative importance of five commonly isolated Phytophthora spp. (Phytophthora alticola, P. cinnamomi, P. frigida, P. multivora and P. nicotianae) from the plantation environment on E. grandis and A. mearnsii seedlings. Overall E. grandis was more susceptible to the tested Phytophthora spp. than A. mearnsii. Phytophthora cinnamomi was the only pathogen that had a significant negative effect on both the host tree species, leading to a reduction in root and shoot weight as well as to death in the case of E. grandis. Phytophthora alticola and P. nicotianae exclusively affected E. grandis and A. mearnsii, respectively. This study updated the current knowledge on the pathogenicity of Phytophthora spp. on two important non‐native commercially propagated tree species from South Africa.