壶瓶山国家级自然保护区野生观赏木本植物资源及其开发利用

对湖南省壶瓶山野生观赏木本植物调查研究结果表明,该区共有野生木本观赏植物81科180属432种,其中乔木273种、灌木111种、木质藤本48种。分析研究了该区野生观赏植物区系特征,按类别列举了各类重要的观赏树种,同时提出了12个重要观赏树种。并对野生植物资源利用的前景提出了建议和探讨。     

大山峰野生观赏植物资源研究

在实地调查、采集、整理、鉴定的基础上,研究了大山峰野生观赏植物资源的多样性、分布区类型和性质.本区共有野生观赏植物(种子植物)122科379属722种(变种、变型),其中乔木189种、灌木224种、藤本67种、草本231种、竹类11种,分别阐述了它们的资源现状、观赏特性和园林用途,并对本区野生观赏植物资源的开发利用和保护进行了探讨.     

太宽河自然保护区珍稀濒危树种多样性与保育

太宽河自然保护区位于中条山的中西端。该保护区有较丰富的珍稀濒危树种,共23科,26属和31种（含变种）,种数占山西省珍稀濒危保护树种的70％以上;其中,4种为在该地长期引栽,27种为自然分布。在当地自然分布的树种中,有国家2级保护种1种,国家3级保护种6种,其余20种为省级重点保护树种;自然分布树种中,24种为极稀少或稀少分布,只有3种为常见或普遍分布。所有树种中,乔木树种23种,灌木种5种,另外3种为木质藤本。最后提出了保护该区珍稀濒危树种的策略。     

海南热带雨林国家公园珍稀濒危观赏植物园林应用筛选

对海南热带雨林国家公园珍稀濒危观赏性植物进行调查,采用层次分析法构建评价模型,筛选出适合应用于海南园林绿化植物资源。结果表明,海南热带雨林国家公园珍稀濒危观赏性植物共31科92属190种,分别为乔木42种、灌木4种、藤本3种、草本141种。层次分析法综合评价值为Ⅰ级（Tj≥4.5）的有37种,其中乔木18种、灌木1种、草本18种,草本均为兰科植物;Ⅱ级（4.5>Tj≥4.0）的有12种,均为乔木;Ⅲ和Ⅳ级的有141种。综合评价值Ⅰ级的37种珍稀濒危观赏性植物具有观赏价值高、广泛的逆境适应能力、人工栽培技术成熟、繁殖栽培成本低、园林应用前景巨大等特点,可为海南园林绿化提供良好的珍稀濒危植物资源。     

德州市园林树种调查与规划研究

通过对本市不同城市绿地类型中36个样点的调查,掌握园林树种207种。其中乔木111种,灌木87种,藤本9种;常绿类44种,落叶类163种;生长状况在较优以上的118种,常见种59种。分析了本市现有园林树木种类构成及其应用分布情况,整理出不同观赏特性树种名录,确定了本市基调树种、骨干树种、一般树种。分析了本市园林树种应用中存在的问题,如常绿树种较少,藤本和灌木的种类及数量都偏少,对本市今后园林树种规划提出了建议,包括应增加常绿树种数量,应多运用有特殊观赏价值的花灌木,加大藤本、灌木应用,实现垂直绿化,丰富季相变化,尤其是增加秋色叶树种的引种和使用。     

广东丰顺野生观赏树木资源评价

首次对广东丰顺县野生观赏植物资源进行系统的调查,查阅相关资料并运用层次分析法(AHP)对丰顺县野生树木进行综合评价。结果显示:丰顺县一级观赏乔、灌木资源有30种,包括多花山竹子(Garcinia multiflora)、大头茶(Gordonia axillaris)、五列木(Pentaphylax euryoides)等,具有极高的园林开发应用价值;二级观赏乔木、灌木资源有薄叶润楠(Machilus leptophylla)、三尖杉(Cephalotaxus fortunei)等45种,其园林开发应用价值较高;三级观赏乔木、灌木资源有33种,包括野漆(Toxicodendron succedaneum)、南酸枣(Choerospondias axillaris),园林开发应用价值一般;四级观赏乔木、灌木资源有25种,包括黧蒴锥(Castanopsis fissa)、铁榄(Sinosideroxylon pedunculatum)园林开发应用价值较低。开发利用价值较高的以樟科(Lauraceae)、山茶科(Theaceae)植物为主。     

哈尔滨市绿化树种的评价与选择

以哈尔滨城区不同景观环境树木分布为基础,通过绿化树种景观评价、古树分布和乡土特点分析,评选出哈尔滨市绿化基调乔木树种3个、灌木树种2个,骨干乔木树种14个、灌木树种12个,藤本骨干树种2个。     

英山县林木种质资源调查及保护利用

通过调查,发现英山县共有木本植物资源90科274属1037种,其中乔木527种、灌木413种,木质藤本97种。古树名木579株,古树群落11个。选定优良林分13块52.76 hm2,树种包括马尾松、黄山松、枫香、麻栎、栓皮栎、乌桕、油桐、日本落叶松等8个树种;初选优良单株16株。并对英山县野生林木种质资源的开发利用提出保护建议。     

长白山区野生材用植物调查研究

3年的调查研究表明,长白山区野生材用植物共有28科、52属、112种,其中乔木24科、42属、93种;灌木9科、11属、18种;木质藤本1科、1属、1种.文中介绍19种主要野生材用植物和11种野生珍稀材用植物,在5个不同景观带的分布情况及其他用途,提出开发利用和保护的具体建议.     

子午岭甘肃段野生观赏植物资源调查分析

为丰富园林植物种类,提高对野生观赏植物资源的开发利用,对子午岭甘肃段野生观赏植物资源进行了调查及统计分析,筛选出了观赏价值较高的野生观赏植物261种,隶属78科175属,其中乔木29种、灌木82种、草本127种和藤本19种。有针对性地提出了子午岭野生观赏植物资源开发利用建议。     

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.