IMPRESSIONS OF FORESTRY IN SOUTHERN EUROPE

The bonding of wood by means of glue has been practised for many centuries.

Adhesion between an adhesive and wood is the result of unbalanced secondary valency forces (Van der Waal's forces) present on the interfaces. It is fundamental to good adhesion that the adhesive must (a) wet the surface it is required to adhere to and (b) penetrate the wood capillaries. The phenomenon of “wetting” is indicated by the contact angle the adhesive forms on the wood surface as well as its ability to penetrate the wood capillaries. Maximum penetration of the capillaries is inhibited in practice due to air becoming trapped in “inkpot” type capillaries caused by the sawblade tearing the wood fibres over in the direction of the cut. Several ways to increase capillary penetration are suggested.

The anisotropic chemical reactivity of wood is theorized in so far that a unit area of wood substance (excluding lumen openings) cut on the cross-sectional plane cannot be as effectively glued as a unit area of wood substance on the radial and tangential plane. This is due to the positioning of the chemically reactive groups on the cellulose chains which are predominantly oriented parallel to the fibre axis.

The engineered design of joints is briefly discussed and mathematical expression given as to how incorrect joint design can be detrimental to the ultimate joint strength.

The general character of the better-known synthetic adhesives is briefly discussed. Little detail is given as excellent hand books exist on this specific subject.     

A BRIEF ACCOUNT OF CHINA S FORESTRY Ⅱ. THE ORIENTATION OF FORESTRY DEVELOPMENT IN FUTURE

<正> In the past 30 years,considerabte progress has been made in China's forestry development. Compared with the advanced countries in forestry,China still has     

回归方程的主成分估计在林业预测中的应用

讨论了林业中使用主成分估计方法克服回归模型复共线性问题。研究和分析了材积方程模型、油松林木平均高与立地环境因子回归模型中存在的复共线性，以及主成分估计方法在建立上述回归方程中的应用。     

基于ALOS数据的巨尾桉蓄积量遥感估测——以广西平南县为例

蓄积量是森林资源监测的一项重要指标,蓄积量遥感估测一直是林业遥感研究的重要内容。本文采用ALOS数据为遥感信息源,以广西自治区平南县优势树种巨尾桉为研究对象,分析选取影响巨尾按蓄积量估测主要的遥感信息和地理信息因子,结合郁闭度实地调查因子,建立了巨尾桉蓄积量估测模型,模型精度达91．18％。     

桉树人工林在广东省森林分类经营中的地位及发展趋势

根据5年来广东省森林分类经营和加速推进速生丰产林建设的实际，阐明桉树是短周期工业原料林的主要树种和商品用材林的重要树种，分析了广东桉树人工林目前面临的主要问题，并展望了其发展趋势。     

广西速丰桉树人工林二元胸高形数模型研究

以广西速生丰产按树人工林719块样地数据为基础,通过优选模型结构,以模型本身为权函数进行加权最小二乘法求解模型参数,研究建立了速生丰产按树人工林二元胸高形数模型。经检验,模型用于林分蓄积估计的总相对误差和平均相对误差均在±2．0％以内,小于规定的±3％;模型总体预估精度达99％以上,大于规定的97％;满足林业数表建模要求。     

广东省林科所树木园现状及营建管理技术浅述

介绍了广东省林科所树木园的发展历史、现状和营建管理技术，并提出了该园存在的主要问题以及今后的设想。     

林业局总体设计的系统思考

林业局总体设计是一项复杂的社会经济系统工程。总体设计在林区开发研究决策序列中占有十分重要的地位和作用。本文结合林业局总体设计的实际需要,对林业局系统的目标、功能和结构优化,以及系统开发设计的效果评价等有关问题进行了系统的研究和探讨。     

论林业生态环境建设的主体地位

本文以首都周围绿化工程为例,论述了林业的生态环境建设主体地位确立的客观性,指出主体地位确立的物质基础在于它对社会经济发展的推动;主体地位确立的条件在于诸多矛盾的正确处理。从而从理论上分析确立了林业的生态环境建设主体地位。为在可持续发展理论指导下,把首都周围绿化工程建设推上一个新台阶提出了具体思路。     

不同年龄尾巨桉林水源涵养能力比较研究

对广西横县镇龙林场不同年龄尾巨桉（Eucalyptus urophylla×E．grandls）人工林凋落物层和土壤层的水源涵养能力进行比较研究。结果表明：随着尾巨桉林龄增大,地表凋落物总量也逐渐增大,5年生林分地表凋落物量最高;凋落物层最大持水量与凋落物量呈显著正相关（P〈0．05）。表层土壤非毛管孔隙度和非毛管孔隙...     

OBSERVATIONS OF A VISITOR ON TIMBER DRYING IN SOUTH AFRICA

The final results are presented of a comprehensive N, P,K and dolomitic lime factorial experiment with Eucalyptus grandis planted on a fully cultivated Mispah soil series. On this marginal site, fertilising had a marked effect on the growth of E. grandis as measured at clearfelling at eight years and three months. The response to single fertiliser elements was greatest for potassium, followed by phosphorus and nitrogen, dolomitic lime having a depressive effect. The best N:P elemental fertiliser ratio was 3:1, while that for P:K was 1:3. Overall, an elemental N:P:K mixture of 3:1:3 was superior, increasing growth with rate of application. Fertilising with 100 g LAN (26% N), 100 g single superphosphate (8,3% P) and 50 g potassium chloride (50% K) increased yields at clearfelling from 56,7 t/ha for no fertiliser to 85.0 t/ha, an improvement of 49,8%. This fertiliser application is recommended for planting E. grandis on shallow soils derived from Ecca shale. Fertiliser treatments also affected form factor significantly, ranging from 0,370 to 0,411 and resulting in volume differences of 11.1% for trees with the same D.B.H. and height. Not only was the response to fertilising highly profitable in itself, but it also rendered the establishment of E. grandis to be viable on an otherwise uneconomically suitable site.     

林业应用回归分析中F检验的一个误用

指出了在林业应用回归分析方法时,使用 F 检验法检验回归关系显著性和进行回归模型选择中常见的一个错误,并对这个错误进行了分析。     

桉树专用肥促生效果研究

对桉树专用肥促进林木生长的效果进行综合评价。通过桉树专用肥与桉树人工林常用的复合肥：肥Ⅰ（荷兰进口）、肥Ⅱ（来自广西）及肥Ⅲ（来自广州）进行施肥生长效果对比试验,结果表明：与肥Ⅱ、肥Ⅲ比,专用肥用作基肥,幼林生长量提高２４％以上;用作追肥,生长量提高１４％以上。大面积推广施用桉树专用肥,１．５年生无性系林分各小班蓄积为２３～５０ｍ＾３／ｈｍ＾２,实生苗林分各小班蓄积为１６～３０ｍ＾３／ｈｍ＾２;２     

河北园林蚧虫名录

本文报道了河北地区为害园林植物的蚧虫8科42属73种,同时对其寄主、为害程度及分布作了介绍。     

ADDRESS BY THE HON. W. A. MAREE,MINISTER OF FORESTRY,TO THE SOUTH AFRICAN LUMBER MILLERS ASSOCIATION

This article deals with statistical inference in forestry reasearch. After an introductory review of definitions, the applications, limitations and range of validity of statistical tests of significance and their use in the analysis of variance are discussed.

The basic principles of various experimental designs are briefly outlined.     

巨尾桉人工林地径与胸径、树高相关模型的研究

根据巨尾桉人工林样木的地径D0、胸径D及树高H观测数据,采用多模型选优法和逐步回归法求解方程,经分析对比后分别建立了地径与胸径、地径与树高相关的2个数学模型:lnD=3.7275-18.6673/D0;H=32.0925-244.050 3/D0。应用这2个模型,配合一元材积表或二元材积表就可测定被伐木的材积。     

雷林1号桉33枯梢病的病原鉴定

雷林１号桉３３号梢病病原菌鉴定为ＢｄｒｙｏｄｉｐｌｏｄｉａｔｈｅｏｂｒｏｍａｅＰａｔ．（Ｌｉｍｅｔａｌ，１９８５）。病原菌菌线体在温度３０～３３℃生长最好，分生孢子在２９～３１℃萌芽率最高，光照强度在１０００～２０００ｌｘ能迅速大量产生子座形成分生孢子，菌体在ｐＨ６．５生长最佳，相对湿度８１％～９０％，最适于菌丝发育。     

论非对称信息条件下林业企业电子商务中的信用问题

通过对非对称信息、信用体系以及电子商务基本理论的解释分析，探讨了中国政府在电子商务基础设施和其他资源方面投入了大量的人力物力但收效甚微的原因，即混乱的经济秩序和信用缺失是导致电子商务发展缓慢的根本原因之一。研究表明，发展电子商务对林业可持续发展具有重要作用，同时信用对林业企业电子商务交易具有决定性作用。