弧结毛瓢虫对铁杉球蚜取食量的测定

弧结毛瓢虫（Ｓｃｙｍｎｕｓｓｉｎｕａｎｏｄｕｌｕｓ）是近年研究发现的一个新种,其取食量的研究未见报导。弧结毛瓢虫属瓢虫科小毛瓢虫属的小型瓢虫,主要取食铁杉球蚜,是控制铁杉球蚜的重要天敌。为了获取弧结毛瓢虫取食铁杉球蚜的生物学资料,１９９７年７月在宝兴...     

樟白轮蚧的四种天敌瓢虫检索表

红点唇瓢虫、湖北红点唇瓢虫、细缘唇瓢虫、中原寡节瓢虫是樟白轮蚧 （ Ａｕｌａｃａｓｐｉｓ ｒｏｓａｒｕｍ ） 的４ 种捕食性天敌, 本文以检索表形式区分它们的成虫和幼虫。     

黄山松上小鞋孢盘菌属一新种*

本文报道在安徽省黄山风景区黄山松上发现的小鞋孢盘菌属（斑痣盘菌目）一新种──中华小鞋孢盘菌（ＳｏｌｅｅｌｌａｃｈｉｎｅｎｓｉｓＹ．－ｒ．Ｌｉｎ，Ｚ．Ｌｉ＆Ｓ．－ｍ．Ｙｕｓｐ．ｎｏｖ．）。对该种作了拉丁文及汉文描述和图解。主模式标本保藏于安徽农业大学森林保护教研室。     

四川大渡河流域不同地点铁杉林瓢虫科多样性比较

文章首次报道了四川大渡河流域的铁杉林瓢虫科种类、数量及发生时间.在3个地点的铁杉林中,共采集到瓢虫48种.对斑小瓢虫Scymnus geminus、华山松小瓢虫S.huashansong、马蹄毛瓢虫S.lycotropus、宁陕毛瓢虫S.ningshanensis为首次在四川报道.3月到11月均可采集到瓢虫成虫,以5月(22种)、6月(25种)和7月(24种)为最多.幼虫出现主要集中在5月.羊厂沟铁杉林是以阔叶为主的针阔混交林,其瓢虫的物种丰富度指数、多样性指数、均匀度指数均远远高于泥巴沟和驷马桥.泥巴沟和驷马桥同属于针叶树占优势的针阔混交林,林内瓢虫科物种丰富度指数较低,但种类优势度高.三地瓢虫组成相似性均处于较低水平.     

毛金竹开发利用研究

毛金竹开发利用研究欧阳训荣刘宝财（江西省遂川县五指峰林场３４３９０９）关键词：毛金竹抚育改造效益分析毛金竹Ｐｈｙｌｏｓｔａｃｈｙｓｎｉｇｒａｖａｒ．ｈｅｎｏｎｉｓ（Ｍｉｌｆ）ＳｔａｐｆｅｘＲｅｎｃｌｅ，又名小毛竹，隶属禾本科竹子亚科刚竹属，广泛分布于...     

A Study on the Soil Water Balance of Protective Forest Ecosystems in Loess Areas in China

ＡＳｔｕｄｙｏｎｔｈｅＳｏｉｌＷａｔｅｒＢａｌａｎｃｅｏｆＰｒｏｔｅｃｔｉｖｅＦｏｒｅｓｔＥｃｏｓｙｓｔｅｍｓｉｎＬｏｅｓｓＡｒｅａｓｉｎＣｈｉｎａＣｈｅｎＬｉｈｕａ，ＹｕＸｉｎｘｉａｏＣＯｌｌｅｇｅｏｆＳｏｉｌａｎｄＷａｔｅｒＣｏｎｓｅｒｖａｔｉｏ...     

七种泡桐生长点的培养

为了探索泡桐种类生长点（茎尖）培养的最佳培养基，从泡桐属７种中的每种选择１－２株成年树，取其０．５ｍｍ长的生长点，分别培养在４种无菌培养基中。这４种培养基是：Ｍｕｒａｓｈｉｇｅａｎｄｓｋｏｏｇ（ＭＳ）培养基、阔叶树（ＢＴＭ）培养基、木本植物（ＷＰＭ）培养基和Ｗｏｌｔｅｒａｎｄｓｋｃｏｇ（ＷＳ）培养基。在ＭＳ、ＢＴＭ和ＷＰＭ培养基中培养３０天后，外植体成活率最高的是毛泡桐、光泡桐和海岛泡桐。在ＭＳ和ＢＴＭ培养基中成活率最低的是白花泡桐和Ｐ．ｃｏｒｅａｎａ。在ＭＳ和ＢＴＭ培养基中成活申为零的是台湾泡桐和兰考泡桐。在相同的ＢＴＭ和ＷＰＭ培养基中３０天的过程，发芽率较大的是毛泡桐和光泡桐。从成活的外植体上面芽的发育数目和芽的平均长度来看，ＭＳ和ＢＴＭ是最佳培养基，但在种与种之间以及植株个体之间．其生长点的成活率有所不同。     

中国茎蜂科分类研究──Ⅴ．华茎蜂属及其近缘属（膜翅目：茎蜂科：哈茎蜂族）

记述了中国哈茎蜂族３属６种，含２新种；裂板华茎蜂（Ｓｉｎｉｃｅｐｈｕｓｉｎｃｉｓｕｓｓｐ．ｎｏｖ．）及红腹华茎蜂（Ｓｉｎｉｃｅｐｈｕｓｒｕｆｉａｂｄｏｍｉｎａｌｉｓｓｐ．ｎｏｖ．）．新种模式标本保存于中南林学院环境与资源系．编制了华茎蜂属及尾茎蜂属已知种检索表．     

山林水环境水生昆虫丰富度及多样性初探

水生昆虫（Ａｑｕａｔｉｃｉｎｓｅｃｔｓ）是自然环境的重要成员，参与构成生物多样性（Ｂｉｏｌｏｇｉｃａｌｄｉｖｅｒｓｉｔｙ）。经对昆明市郊山林水环境设８个样点调查，共获水生昆虫５目１５科３０种。其中半翅目（Ｈｅｍｉｐｔｅｒａ）和鞘翅目（Ｃｏｌｅｏｐｔｅｒａ）为两大优势类群。样点Ｓ一Ｖ和Ｓ一Ⅵ水生昆虫种类较多，物种丰富度（Ｓｐｅｃｉｅｓａｂｕｎｄａｎｅｃ）依次为２１和１９；样点Ｓ一Ⅶ和Ｓ一Ⅵ的半翅类昆虫多样性指数即Ｓｈａｎｎｏｎ一Ｗｉｅｎｅｒ指数较大，分别是１．５３００和１．５１２２。     

扶绥中东金花茶新种

扶绥中东金花茶新种梁盛业（广西林科院）ＣａｍｅｌｌｉａａｃｈｒｙｓａｎｔｈａＣｈａｎｇ＊ｅｔＳ．Ｙ．Ｌｉａｎｇ，ｓｐ．ｎｏｖ．Ｓｕｂｇｅｎ．ＴｈｅａＣｈａｎｇ，Ｓｅｃｔ．ｃｈｒｙｓａｎｔｈａＣｈａｎｇ，Ｓｅｒ．ｃｈｒｙｓａｎｔｈａｅＣｈａｎｇ．Ｓｐｅ...     

长苞铁杉群落结构特征研究

长苞铁杉属于珍稀濒危植物，被列为国家Ⅲ级保护植物。在样地调查材料的基础上，对福建省天宝岩自然保护区珍稀植物长苞铁杉群落结构、群落数量特征、种群动态进行了深入分析与研究。并对长苞铁杉濒危机制及保护措施进行了探讨，为长苞铁杉林的保护提供了理论依据。     

珍稀濒危植物长苞铁杉种群密度效应模型

植物种群的调节是一个多因素的复杂过程,通过对种群的出生、死亡和生长等过程的控制,使种群的数量维持在生境可以容纳的最大水平上.尽管影响种群动态的因素可分为密度制约因素和非密度制约因素,但在植物中,尤其对木本植物,主要是密度制约起着种群调节与控制的作用,这种调控的过程反映了种群对群落结构及相应环境条件的适应与利用,主要表现为植物种群密度效应(江洪,1992).种群密度效应一直是种群生态学领域研究的热点.前人在研究植物种群密度拥挤效应规律时,提出了大量理论或经验的表达式(Yada et al.,1963;唐守正,1993;方精云,1995;Hozumi,1977;1983;John et al.,1994;张大勇等,1985;吴承祯等,2000c;2000d;安藤贵,1968;洪伟等,1996;陈辉等,1992),反映了植物种群数量动态受多种限制因素影响,如有限的资源、空间以及种内、种间植物个体对资源的竞争,导致种群数量发生变化,即为密度效应     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.