湘西自治州的野生油料树种

湘西自治州,植物资源丰富,在华中植被区系上,独具特色。其中野生木本油料资源,品种多、潜力大、质量好,是油料植物中的一大优势。根据调查收集的部分资料统计:林木种子含油率在15％以上,有43科、83个树种。其中种子含油率在40％以上,有25科、32个树种,如黄连木(Pistaciachinensis Bunge)种子含油率42.46％、亮叶水青岗(Fagus lucida Rehd et Wils)     

甘肃南部生物质能源树种资源调查及开发利用

甘肃南部有丰富的生物质能源树种,据调查有油脂油料植物30科95属341种,其中可作为燃料油的植物有80多种。介绍10多种重要能源树种形态特征、地理分布、种群结构、含油率,提出了开发利用生物质能源树种的建议。     

兰州市行道树树种现状调查

通过对兰州市区道路树种的栽植概况调查,结果表明：目前兰州市区共有行道树树种18种,其分属10科12属,乡土树种占61%,其中刺槐、臭椿、旱柳、白蜡等树种后期病虫害严重,作为行道树将在兰州市区逐渐淘汰。并通过对行道树种的选择,筛选出适宜市区可推广应用的行道树种类有21种,分属13科17属,乡土树种占62%。     

乌桕的培育与抚育管理

乌桕为我国南方重要工业油料树种,出油率高达40%以上,是目前木本油料树种中出油率较高的一种,是理想的能源树种之一。乌桕木材纹理致密,有光泽,不翘裂,可作家俱、车辆、雕刻等用材;乌桕为优良的乡土树种,其树冠整齐,夏叶青绿,秋叶红艳,冬日则白色乌桕子挂满枝头,经久不凋,还有抗风力强、抗大气污染的特性,是行道树、护堤林或城市绿化的优良树种。     

南岳衡山野生油料植物资源及其特征

采用线路调查和样地调查相结合,并参阅前人已有的研究成果及文献资料的方法,对南岳衡山野生油料植物资源及其特征进行研究。结果是:南岳衡山有油料植物(种子植物)309种,归属于93科180属,其中油脂植物80科165属263种,精油植物33科46属80种。油料植物科含属一级的大小级中,随属级的大小级增加,科的数量逐渐减少,油料植物属有相对集中于少属科的倾向;随种级的大小级增加,科的变化规律不明显。油脂植物科含属一级和含种一级的大小级均随大小级的增加而科数逐渐减小,以含1属(种)和2～4属(种)的科占绝大多数。精油植物以含1属的科和1种的科占绝对优势,没有≥10属和≥10种的科。油料植物以木本植物为主,占70.55%;草本植为辅,占29.45%。油脂植物中木本植物占78.71%,草本植物占21.29%;精油植物木本植物占45.00%,草本植物占55.00%。含油器官大多为果实、种子。起始含油量(19.0%)以上的野生油脂植物140种,占全区油脂植物53.23%;油脂植物中有大量的富油植物(含油量≥50.0%)和较富油植物(含油量40.0%～49.9%),其含油量最高达73.8%。油脂植物的脂肪酸组成中,有富含油酸、亚油酸、亚麻酸的植物,还有一些类群富含低碳原子脂肪酸、桐酸、癸酸、棕榈酸等特用脂肪酸。     

乌桕主要害虫及防治策略

乌桕Sapium sebi．ferum Roxb属大戟科乌桕属,别名木蜡树、乌桕籽、木梓、桕子柴等,为落叶乔木。乌桕是我国的原生树种,据记载,在我国已有1000年以上的栽培和利用历史。乌桕的栽培十分广泛,是山区、丘陵、平原及城市园林中常见的树种。乌桕分布范围遍及全国19个省、市、区,华中地区是乌桕自然分布的中心地带。     

海南省热带雨林的保护和利用

海南是我国热带雨林和热带季雨林原生地之一。是地球上同纬度地区的“绿色明珠”。据资料记载，海南已发现植物4200种，隶属198科1109属，其中有乔灌木1400多种，占全国乔灌木种类的28．6％；在800多种乔木中，有458种列入国家的商品材，200多种为珍贵树种；还有药用植物2500多种，果树142种，油料植物89种。     

山东鲁山省级自然保护区木本油料树种资源调研

对鲁山省级自然保护区木本油料树种资源进行调查,筛选出种子(种仁)含油率在20%以上的树种有21科、55种,对开发利用现状进行了阐述,并就木本油料树种资源的保护、开发利用等方面提出建议。     

乌桕金带蛾在贵州的分布与危害

乌桕[Sapium sebiferum(L.)Roxb.]是我国一种重要的木本油料树种。我省乌桕品质尤为优良,据测定12个品种(类型)含油率为44.1%～56.56%。近年在桕树上乌桕金带蛾(Eupterotesapivora Yang.)连年成灾,生产受到很大损失,桕林生长不良,结籽少,质量差,桕耔出油率下降,酸价增高。为此,我们于1968～1989年在我省乌桕主产区为中心的地区,对乌桕金带蛾进行了较为深入的调查。现将其在贵州的分布与危害报道     

呼和浩特树木园生存与发展问题探讨

呼和浩特树木园位于呼和浩特市赛罕区,内蒙古林业科学研究院内,隶属于林科院管理,占地面积330亩。树木园始建于1954年,是我国建设较早的专业植物园之一。园内设有裸子植物区、被子植物区、沙生植物区、水生植物区和苗圃等5个专业区。现有乔灌木树种达500种以上(包括变种),分属55科、130属,其中,经济树种、观赏树种和珍稀树种36科、81属、256种,而且70%以上是第一次引入本地区;针叶树引种62种,其中较丰富的是云杉属,20种。1999年呼和浩特树木园被中国科协命名为全国科普教育基地。内蒙古农业大学、内蒙古师范大学等大中专院校和广大中小学生经常来园进行植物学实习和生物课教学,已成为内蒙古地区重要的科普教育宣传基地。     

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.     

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.     

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.     

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.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

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.