不同绿地类型对城市小气候的影响

通过HOBO便携式气象站测定了城市林荫道、草坪、广场3种绿地类型的气温、相对湿度和辐射强度。分析了不同绿地类型上的温度、湿度及太阳辐射变化情况,比较了不同绿地类型对城市小气候的影响。结果表明,随着辐射强度的增强,林荫道有较好的降温保湿效果,并且林荫道与广场的最高温差可达2.76℃,相对湿度的最高差值可达12.5%。在晴朗无风的条件下,随着辐射强度的变化林荫道上温度和相对湿度变化比较缓慢,所以随着辐射强度的增强,林荫道上的气温低于草坪,相对湿度则高于草坪,当辐射强度逐渐减弱时,林荫道上的气温逐渐高于草坪,相对湿度则低于草坪。     

影响牧草种子萌发和种苗存活的因素探讨

补播是退化天然草植被恢复过程中的主要措施,种子萌发与种苗存活是植物生活史的关键时期,它可以潜在的影响到植物种群的结构和群落的组成,影响种子萌发和种苗存活的因素不同,所以有必要了解影响这两个过程的因素,提高种子的萌发率和种苗的存活率,加速植被恢复进程.     

城市绿地实施植物多样性的探讨

从城市绿地植物多样性的效益,实施城市绿地植物多样性应遵循的原则以及实施城市绿地植物多样性应采取的措施等方面,论述了在城市绿地中选用多种植物的必要性;同时,对在城市绿地中如何实现植物多样性提出了实施的原则和措施。     

Ecological and economic benefits of cross-boundary coordination among private forest landowners

A significant challenge facing forestry today is managing private forests sustainably in the face of continued ownership fragmentation (i.e., parcelization). Cross-boundary coordination––where forest practices are coordinated across multiple properties––has been proposed as a mechanism by which landscape-level ecological and economic benefits may be accrued in privately-owned landscapes, but few tests of the concept exist. Using a case study approach, we quantify the extent to which ownership-centric forest management is constrained by economies of scale and misses opportunities to achieve ecological objectives in three landscapes in Wisconsin, USA. Methods are based on existing forest management plans and include spatial analysis of patch distributions and shapes, simulation of forest practices, and calculation of net present value over a 20-year horizon. Our results indicate substantial opportunity for cross-boundary coordination: between 62% and 88% of the managed properties within our study landscapes were adjacent to other properties with forest management plans. At a patch scale, coordination can result in ecological benefits that can be accrued into the future (e.g., maintenance of large patches and natural ecosystem boundaries). Because these landscapes are already highly parcelized, however, coordination offers little opportunity to impact the overall landscape-scale structure. Greater economies of scale can also be gained by coordinating forest practices, including increases in the size (16–99%) and volume of timber sales (16–94%), and a modest economic advantage (3–6%). As first steps, investment in data infrastructure and professional training are required to support cross-boundary multi-ownership forest management. More broadly is the need to shift from policies and practices that are largely ownership-centric to those that include and better incorporate landscape-centric perspectives.     

黄土高原沟壑区沟坡地苹果优质丰产栽培技术体系

确立了黄土高原沟壑区沟坡地为优质苹果生产地带 ,建立起沟坡道路防蚀体系 ,春栽改秋栽 ,量化施肥、灌水、修剪 ,生态防治病虫害 ,加强优果生产和采后处理等是黄土高原沟壑区沟坡地带优质苹果生产的主要技术措施。     

干旱区土地退化生态系统的评价方法

本文简要介绍了我国干旱区的二种分类方法、分布面积和自然特点。干旱区土地生态系统退化的主要类型有草场退化，而养耕地退化和灌溉地退化，国内外各种退化类型的分布面积。提出退化土地生态系统评价原则，主要退化土地的评价指标体系，评价因子权重的确定方法，综合评价方法及地理信息系统的应用。     

生长在矿区废弃地的栾树混交幼林生物量研究

对湖南湘潭锰矿矿业废弃地营造林的3．5-4．5年生栾树、杜英混交林进行了生物量研究．结果表明:林分密度为3 240株／hm2,栾树单株生物量为1 175-1 958 g,杜英为544-909 g;林分生物量为3125-5211．00 kg／hm2,林分净生产量为893．00- 2085．48 kg／(hm2·a)．现林木生命力强,生长旺盛,林分生产潜力大．为矿区废弃地的植物修复提供了优良树种．     

大明山退化生态系统的植物区系分析

对大明山中山区和低山丘陵区退化生态系统的植物区系进行比较分析 ,揭示了不同区域退化生态系统植物区系的基本特点和性质 ,为合理利用植被资源、维护生物多样性提供参考。     

三江平原退化湿地土壤物理特征变化分析

针对不同退化程度的湿地土壤物理特征的变化进行了分析。首先对退化湿地土壤剖面特征进行了阐述,然后分析了退化湿地土壤的温度特征变化、电导率状况变化、土壤的水分特征变化和土壤容重变化。研究表明,不同退化程度的湿地土壤具有不同的土壤物理性质,在未退化湿地→轻度退化湿地→中度退化湿地→重度退化湿地→已垦湿地(农田)的湿地退化研究样带上,湿地土壤温度呈现逐渐升高的变化趋势、土壤电导率呈降低变化、土壤水分呈降低趋势、土壤容重则呈现升高的变化规律。土壤表层与下层相比较,土壤表层温度、含水量与容重均高于土壤下层;在电导率的变化中,除了未退化湿地土壤的下层高于表层以外,其它退化状态的湿地土壤均为表层高于下层。另外,对退化湿地土壤的各物理特征在空间距离上的退化过程进行模型模拟,发现指数增加(或分解)模型能够较好地模拟出湿地土壤物理特征的空间退化过程。本研究将有助于理解退化湿地土壤物理特征的变化规律和查明湿地的退化机理,为退化湿地的恢复与重建研究奠定科学基础。