河北怀来官厅水库国家湿地公园

正河北怀来官厅水库国家湿地公园,2014年申请建设,经过五年不懈努力,于2019年12月25日经检查验收被国家主管部门正式批准成为国家级湿地公园。规划中的湿地公园西起下花园区洋河进入怀来境内交界处,东至怀来与延庆交界处,南北至官厅水库库堤。东西横跨47公里,南北纵跨26公里,规划总面积20.3万亩,湿地率97%。公园内分别划定生态保育区、恢复重建区、科普宣教区、管理服务区和合理利用区等5大区域,分别开展湿地保护与修复、科研监测、     

对城市湿地公园规划建设的思考

城市湿地公园作为现代城市发展过程中一种新的绿地类型,生动地体现出城市与湿地的融洽结合、人与自然的融洽结合。以位于河南黄河湿地国家级自然保护区内的三门峡市天鹅湖国家城市湿地公园为例,探讨了城市湿地公园在规划、建设及管理中一些问题的认识与思考。     

基于水资源保护湿地公园规划设计——以山西太岳沁河源国家湿地公园为例

湿地资源在自然环境中是重要资源,保护自然资源不被破坏是做湿地公园规划的重要目标,水环境在湿地中尤为重要。针对水资源保护,对湿地公园进行规划设计。本文以调查研究为主,对全国湿地类型进行简要分析,对山西省湿地资源进行调查,以山西太岳沁河源国家湿地公园为例,对公园规划定位,结合湿地公园的特点和位置、以水资源的保护为特色,对公园进行功能区划分,突出湿地保育区、恢复重建区的重要性。本湿地公园以双泉眼为特色,拥有复杂、综合的湿地生态系统,水资源的保护尤为重要。针对公园现状,采取一系列措施,保持湿地水资源的稳定,减少水资源的流失。     

重庆阿蓬江国家湿地公园总体规划构思

通过对重庆阿蓬江国家湿地公园现状调查和湿地资源、风景旅游资源的分析研究,按照景观资源的分类要求对湿地公园的景观资源进行综合评价。简要分析项目实施的优势和劣势,在突出生态保护优先的原则下将湿地公园划分为舟白湿地保育区、官渡峡湿地游赏区、蒲花河湿地体验区、濯水湿地服务区、神龟峡湿地探秘区、两河湿地休闲区等6个功能区和1个外围保护地带,并有针对性地提出保护保育规划、生态旅游规划、植物景观规划、土地利用规划、居民社会调控规划、科研和监测规划等相关规划。     

颍州古西湖湿地公园生态系统的恢复与发展研究

从公园湿地建设规划、公园现有物种、生态分布等方面分析了颍州西湖湿地公园概况,并提出了颍州古区西湖湿地公园生态系统恢复建议与对策.     

西平县引洪河省级湿地公园规划设计

以西平县引洪河省级湿地公园为例,根据湿地现状、地理位置以及当地人文历史情况,遵循湿地公园规划的指导思想和基本原则,将湿地公园划分为湿地保育区、合理利用区、宣教展示区和管理服务区4个功能区,形成“一线,两岸,四区”的规划布局。并通过开展湿地生态保护、科普宣教、科研监测等工程措施,构建以保护生态环境为核心,集湿地保护、科研宣教、地域文化传承、休闲观光为一体的省级湿地公园。     

昆明捞渔河国家湿地公园规划构思

对云南昆明捞渔河湿地资源现状、区位交通、湿地文化及周边环境进行充分调查和深入分析,结合滇池生态系统修复及治理经验,以保护优先、科学修复、合理利用、持续发展为原则,将捞渔河湿地公园规划设计为集湿地保护与恢复、滇池治理示范、公众湿地生态体验及科普宣教于一体的城市近郊公益型国家湿地公园。根据区划原则,将公园划分为湿地保育区、恢复重建区、宣教展示区、合理利用区和管理服务区5个功能分区,并根据各功能区定位规划其建设目标及主要建设内容。     

南洞庭湖湿地生态旅游品牌的定位与开发

分析了南洞庭湖湿地生态旅游资源,探讨了南洞庭湖湿地生态旅游品牌的定位与开发,从国家级湿地公园,项目规划、项目建设等方面提出了相应的对策与建议。     

云南晋宁南滇池国家湿地公园景观（一）

坐落于滇池南部的云南晋宁南滇池国家湿地公园是昆明唯一的国家湿地公园,本文从南滇池湿地公园的五大功能分区(湿地保育区、合理利用区、宣教展示区、湿地恢复重建区、管理服务区)探讨了其湿地景观,并倡导了南滇池湿地公园的健康理念。公园的南滇池沙滩将湿地与旅游完美结合,水生花卉、蔬菜浮床培育种植创造了湿地公园合理利用新模式。南滇池湿地公园作为国家湿地公园,其功能分区的设置、湿地合理利用模式的开发、对湿地科普宣教功能的重视以及健康理念与湿地景观的融合,对于其他湿地公园的建设是具有参考和借鉴价值的。     

溱湖国家湿地公园

溱湖国家湿地公园,是2005年经国家林业局批准设立的全国第二家、江苏首家国家级湿地公园,也是省级名胜风景区、国家AAAA级旅游景区。溱湖国家湿地公园,规划面积26平方公里。湛蓝的湖泊、交织的河网和星罗棋布的洲滩岛屿,以及特有的湿地生态环境和里下河水乡民俗文化,是其独有的     

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.     

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.     

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.     

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.     

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.