广州市域林带的规划与实施

把广州市域林带分为市域主干道绿化带、市域生态廊道、市域组团绿化隔离带、市域滨水林带。依据城市可持续发展指导思想 ,提出生态优先、效益兼顾 ,一体化、可操作 ,因地制宜、适地适树 ,分期实施、稳步推进的原则。规划过程中重点突出了 8条主干道绿化带的“一路一景”特色 ,7条新建生态廊道的城市生态安全对策以及丰富城市形象的组团绿化隔离带和规划建设有岭南风情的滨水生态风光带 ,并提出了规划实施过程中用地政策、资金筹措、管理养护、科技开发等方面的保障措施。     

广州市城市森林体系规划建设探讨

针对广州市林分质量差、林种结构不合理和龄组比例不协调等城市森林现状,阐述了广州市城市森林体系规划建设的基本原则和目标,构建了广州市内环、中环和外环分项规划框架,重点讨论了市域林带(包括主干道绿化带、市域生态廊道、市域滨水林带)和城市林区(包括生态景观林区、水源涵养林区、商品林区)、城区花园式单位、自然保护区与野生动物栖息地等重点项目的规划建设问题.     

济南市中心城生态隔离带详细规划研究

生态隔离带对于阻隔城市组团、防止环境恶化具有非常显著的作用。本研究充分结合上位规划及实际用地现状,从规划控制、指标限定、城乡统筹、生态保护、建设指导等方面入手,形成济南市生态隔离带详细规划方案。"一横五纵多廊"的生态隔离带将与南部山区相连接,环绕城市各片区组团,构建起完整的绿色生态骨架,创造宜居的现代都市生态环境。这也是生态隔离带专题研究及详细规划层面的一次深入突破。     

凤庆县森林网络构建途径

从凤庆县创建"森林县城"的森林网络建设多项指标着手,结合森林城镇建设的基本原则,围绕交通廊道绿化、水系廊道绿化、村庄绿化、城市公园绿化等内容,针对凤庆县城镇建成区绿地乔木应用比例较低,生态防护隔离带林分质量低等问题,提出创建森林县城所必须的森林网络构建思路。阐述森林网络构建原则、理念、功能定位和规划布局,并提出统筹兼顾、协调发展、完整立体、强化保护管理机制等建议。     

临沧市国家森林城市建设规划研究

对临沧市创建森林城市的条件进行SWOT分析。从市域和城市主城区2个层次,分别探究森林城市建设规划的规划思想和布局理念,将市域城市森林网络体系构建成"一核、二网、三廊、八片多点"的森林景观格局;按照"基质—斑块—廊道"的生态体系,将城市主城区布局为"一轴、五片、绿网纵横"的城市森林景观格局。并详细阐述市域和城市主城区2个层次森林体系布局的主要内容。     

绿树红花绕滨州

山东省滨州市结合新城区建设,把城区外环林带作为“城市增靓”工程的重点来抓。自2002年冬季开始,已完成绿化建设里程29.8公里,外环的轮廓在一片绿意中渐渐浮现出来。严把规划设计关,全力打造精品工程。滨州市城区外环绿化设计是:沿道路和河道两侧全线贯以林带配置,在交叉路口和转弯处配置片林或景点,点、带、面结合,实现防护效能和观赏价值的有机统一。外环线绿化带设主林带和副林带。主林带以河、路为依托,栽种高大乔木树种,中间栽植3行乔桑,作为绿化隔离带,形成混交林结构模式;河两岸每侧栽植一行金丝垂柳。副林带在主林带外围辐射,由冬…     

广东省各地、各部门共同推进生态景观林带建设

胡锦涛同志在2011年视察广东时指出,要"加强重点生态工程建设,构筑以珠江水系、沿海重要绿化带和北部连绵山体为主要框架的区域生态安全体系,真正走上生产发展、生活富裕、生态良好的文明发展道路"。为贯彻落实这一重要讲话精神,广东省政府于2011年出台了《关于建设生态景观林带构建区域生态安全体系的意见》,决定在全省统一规划建设23条、1万公里、805万亩的生态景观林带,要求把生态景观林带工程建设作为继"十年绿化广     

哈尔滨工程大学校园绿化改造方案

本文通过对哈尔滨工程大学绿化现状的分析,在规划中,提出了"一园、二区、三空间、四廊道、六组团"整体绿化景观,使设计更科学、布局更完整、结构更清晰。在新校区规划为体现学校从"发现—研究—收获"的这一发展历程。提出"新校区、新建筑、新景观"的思想,设计出简洁、现代、生态且充满创造精神的新景观。结合不同的区域特点分别提出了详细设计方案,展现出知识不断求索创新、积累升华的过程。     

北京向“绿色奥运”迈进

2001年，北京在申办2008年奥运会之时，向世界承诺，将把第29届奥运会办成一届绿色的奥运会。6年来，北京的绿化美化建设全力提速。今年，北京将完成申奥时对世界承诺的市区林木覆盖率、山区林木覆盖率、绿色生态屏障、“五河十路”两侧绿化带、市区绿化隔离带、城市绿色覆盖率、自然保护区面积等7大绿色指标，达到“办绿色奥运，建生态城市”的目标。     

吉林三岔子国家级森林公园旅游产品规划的思考

项目按"二道三区四组团"的总体布局进行规划,即由二条景观廊道连接三个风景区,重点建设四个旅游组团.旅游产品规划将园内旅游资源的合理组合,衍生出漂流观光体验游、射击狩猎游、休憩度假游、峡谷探险游和生态采摘观光体验游等旅游项目.     

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.     

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。