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指出了城市建筑的绿化直接关系到居住环境的质量,探讨了建筑与绿化之间的关系,以及建筑绿化的意义和形式,分析了建筑绿化在社会发展和创造和谐人居环境中的重要性。 相似文献
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在大自然中,森林与环境的关系十分密切,它们互相影响,互相作用,始终处在不断的矛盾或统一之中,构成对立统一的关系。环境的改变会引起森林发生相应的变化,而森林的变化又会作用于周围的环境。森林的一切变化都是它与环境相互影响、相互作用的结果。 相似文献
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随着国民经济的快速发展以及人们生活条件的逐步提升,人们对于更加舒适、健康、环保的居住环境追求愈发明显。我国现有人居环境对木结构建筑的设计产生了重要影响,木结构建筑发展方向因此得到改变。对我国木结构建筑设计的发展现状、人性化表现以及与人居环境之间的协调性进行综合性阐述,为研究人居环境对木结构建筑设计的影响以及木结构建筑设计的发展方向提供一定的理论支持。 相似文献
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园林街景已成为建筑景观、自然景观、各种人工景观等与城市道路之间的链接.以杭州蚕花港街头游园设计为样本,阐述了该街头游园的设计原则、设计理念、具体设计的过程,认为游园设计要结合当地的文化内涵,延续历史文脉,恢复和提高景观活力,力求做到自然景观与人文景观的互相融合,互相衬托. 相似文献
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IntroductionMaskedciVet(Paguma18vata),Mammalia,Viverridae,ismainlydiStributedinShanxi,Sichuan,Tibet,Yunnanprovinces,etc..Itsmeatisdeliciousandhasspecialflavor.Itiseasytoberaisedartificially,withhighproduCtivity.Nutria(MyocasterCOypus),Rodentia,Capromyidae,originatedinArgentina,Chili,etc.insouthAmerica.Itisakindofherbivoresfur-bearer.itsartificialraisinghassuchmeritsasdurablefurandlowcostandhighproduCtivity.MaskedcivetandnutriahavehigheconomicvalueandwideprospeCtofutilization.Atpresen… 相似文献
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Alaa A. Bashandy Alaa E. El-Habashi Ahmed K. Dewedar 《Wood material science & engineering》2018,13(4):241-253
This research aims to study the feasibility of repair and strengthening of timber cantilever beams used in historic buildings. It is conducted to investigate the feasibility of using different valid materials and techniques to repair and strengthen timber cantilever beams in new and historic timber buildings. The study is performed in terms of structural performance as well as historic and architectural values. An experimental program of several different materials and techniques is executed. The results are driven in terms of initial cracking load, crack propagation for the tested samples at different loading stages, deflection values, and failure load for each repaired or strengthened material and technique. The main variables are timber types (new and historic), repair and strengthening materials (steel plates, Glass Fiber Reinforced Polymer wrap, and Carbon Fiber Reinforced Polymer laminates), repair or strengthening techniques (near surface mounted and externally bonded system), and cantilever length (1000 and 1250?mm). Test results indicated that using steel plates, glass fiber wrap, and carbon fiber laminates increases the value of failure loads and decreases the deflection at both; repaired and strengthened timber cantilever beams compared to control beams. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(7):577-584
ABSTRACTThe connection between chemical composition and anatomy of wood is poorly studied. Abiotic and biotic growth conditions affect the synthesis of structural compounds and the anatomy of wood at the same time as they affect growth. In this study, the wood chemical composition, and connections between wood chemistry and anatomy were studied in downy birch (Betula pubescens Ehrh.) grown on four growth sites possessing mineral and peat soils. Lignin, holocellulose, extractive and ash contents, and effective heating value were analysed and compared with libriform fibre double wall thickness and lumen diameter, vessel size and number, and ray and axial parenchyma numbers. Measured lignin and extractive contents were exceptionally high and holocellulose content low. Correlations between wood anatomy and effective heating value were partly different on different soils. Correlations between holocellulose and anatomy were the opposite of the correlations between other chemical compounds and anatomy. The significant correlations between chemical composition and anatomy were commonly opposite in trees grown on peat than in trees grown on mineral soil. Particularly, vessel characteristics and fibre wall thickness correlated significantly with wood chemistry in trees grown on mineral soil. The connections between wood anatomy and chemistry proved to be soil-dependent. 相似文献
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国内外重要的植物分类学与系统学文献均认为:木犀科和属(白蜡树属)植物只有2心皮的子房和果实。目前仅有2篇文献认为木犀科和属植物还具有3或3和4心皮的子房。作者在对属植物的果实进行研究时,发现属植物果实具有2心皮、3心皮、4心皮和6心皮4种类型,首次发现了属植物具有6心皮的果实。这一发现具有一定的系统学意义。 相似文献
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Temuulen Tsagaan Sankey 《New Forests》2008,35(1):45-55
Spatial patterns, rates, and density of encroaching forests into adjacent grasslands have important implications for long-term
land use management and resource planning. This study examines the effects of Douglas-fir (Pseudotsuga menzeisii) and aspen (Populus tremuloides) regeneration mechanisms on sucker and seedling spatial patterns, distance from adult trees, and density in encroaching forests.
A total of 8,924 aspen suckers and 1,244 Douglas-fir seedlings were counted and mapped in 2,920 quadrats (5 m × 5 m) in 106
plots along a lower forest-grassland ecotone in the Centennial Valley, MT, USA. Sucker and seedling spatial patterns were
analyzed using Morisita’s I index. Average sucker and seedling density per quadrat and distance from adult trees were estimated for each plot and compared
between aspen-dominated plots and Douglas-fir-dominated plots using ANOVA tests. Aspen suckers were established in a clustered
spatial pattern at a significantly higher density and a significantly shorter distance from the adult trees. In contrast,
Douglas-fir seedlings were established in varying spatial patterns at a significantly lower density and a significantly greater
distance from the adult trees. Forest encroachment into the adjacent grassland in the Centennial Valley is occurring in contrasting
patterns and at varying rates and densities due to the difference in aspen and Douglas-fir regeneration mechanisms. 相似文献
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G.W.W. Wamelink H.J.J. Wieggers G.J. Reinds J. Kros J.P. Mol-Dijkstra M. van Oijen W. de Vries 《Forest Ecology and Management》2009
Changes in the Earth's atmosphere are expected to influence the growth, and therefore, carbon accumulation of European forests. We identify three major changes: (1) a rise in carbon dioxide concentration, (2) climate change, resulting in higher temperatures and changes in precipitation and (3) a decrease in nitrogen deposition. We adjusted and applied the hydrological model Watbal, the soil model SMART2 and the vegetation model SUMO2 to asses the effect of expected changes in the period 1990 up to 2070 on the carbon accumulation in trees and soils of 166 European forest plots. The models were parameterized using measured soil and vegetation parameters and site-specific changes in temperature, precipitation and nitrogen deposition. The carbon dioxide concentration was assumed to rise uniformly across Europe. The results were compared to a reference scenario consisting of a constant CO2 concentration and deposition scenario. The temperature and precipitation scenario was a repetition of the period between 1960 and 1990. All scenarios were compared to the reference scenario for biomass growth and carbon sequestration for both the soil and the trees. 相似文献
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Agroforestry research in academia and government and non-governmental agencies began by focusing on biophysical aspects. As
this science represents a series of practices implemented by individual farmers, it requires in-depth social and economic
analyses to assess economic feasibility of agroforestry systems, factors influencing the adoption of agroforestry, monitor
the relevance and effectiveness of investigations, and guide future research efforts. This study presents literature dealing
with socioeconomic issues in agroforestry research from interdisciplinary peer-reviewed journals, book chapters, and gray
literature from 1992 to 2002. Over 500 publications were analyzed to determine relative dominance of geographical regions,
types of analyses, agroforestry technologies, and socioeconomic issues. Trends were examined over time and by region. Overall,
the body of literature exhibits an increasing trend toward regional and analytical diversity over time. Some deficiencies
of regional and thematic nature were observed, which included underrepresented temperate regions and technologies such as
riparian buffers, as well as only a small number of papers dealing with gender and property rights. These suggest opportunities
for future investigations. 相似文献
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杨树修枝理论和技术研究进展 总被引：4，自引：0，他引：4
杨树修枝是杨树速生丰产后期经营管理中一项重要的措施,本文综述了修枝对杨树生长、材质以及林下经济的影响。修枝对杨树树高、材积生长量的影响因树种、立地、修枝强度的不同规律不同;修枝会降低胸径的生长量,提高萌枝数量,但可以提高材质。修枝对材质的影响表现在尖削度减小、节子减少、形数和形率增加等。修枝可以增强林下作物光合作用,促进林下植物生长,提高产量;实践中,修枝强度、起始年龄、修枝季节应因树种而异。目前,对于杨树修枝的研究多为短期的、单方面的,系统综合研究尚需进一步加强。 相似文献
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杜鹃花种子休眠打破技术的研究 总被引：1，自引：0，他引：1
以杜鹃花的两个种映山红（R.simsiiPlanch.）和蓝荆子（R.mucronulatumTurcz.）的种子为实验材料,用不同浓度的硫酸、有机溶剂和氧化剂处理种皮并分别处理不同时间,在培养皿中进行萌发对比实验;用赤霉素、层积及变温处理种子在培养皿中进行萌发的对比实验。结果表明,40%硫酸处理种皮20min、100%乙醚处理种皮20min、5%次氯酸钠处理种皮30min、层积处理及10%赤霉素处理24h均能有效提高映山红种子萌发的发芽率、发芽势和发芽指数;20%硫酸处理种皮10min、层积处理和赤霉素处理能显著提高蓝荆子种子发芽率、发芽势和发芽指数,100%乙醚处理10min能明显著提高蓝荆子种子的发芽率。 相似文献
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Risk assessment can provide a robust strategy for landscape-scale planning challenges associated with species conservation and habitat protection in Pacific Northwest forests. We provide an overview of quantitative and probabilistic ecological risk assessment with focus on the application of approaches and influences from the actuarial, financial, and technical engineering fields. Within this context, risk refers to exposure to the chance of loss and typically involves likelihood estimates associated with outcomes. Risk assessment can be used to evaluate threats and uncertainty by providing: (1) an estimation of the likelihood and severity of species, population, or habitat loss or gain, (2) a better understanding of the potential tradeoffs associated with management activities, and (3) tangible socioeconomic integration. Our discussion is focused on threats identified as important influences on forest biodiversity in the region: natural, altered, and new disturbance regimes, and alien and invasive species. We identify and discuss three key challenges and opportunities specific to these threats and quantitative and probabilistic approaches to risk assessment: (1) endpoint selection and calculation of net value change, (2) probability calculations and stochastic spatial processes, and (3) evaluation of multiple interacting threats. Quantitative and probabilistic risk assessment can help bridge the current gap between information provided by general assessment and planning procedures and the more detailed information needs of decision and policy makers. However, management decisions may still fail to win public approval because important risks and issues can be missed or perceived differently by stakeholders. Stakeholder involvement at the inception of a risk assessment can help attenuate these problems. Stakeholder involvement also provides opportunities to communicate information that can influence public risk perceptions and attitudes. 相似文献