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31.
The environmental yardstick for pesticides has been developed as a tool for farmers to select pesticides with the least environmental impact and to quantify the impact of their use at the crop/farm level, regional level and national level. For each pesticide the yardstick assigns environmental impact points for the risk to water organisms, the risk of groundwater contamination and the risk to soil organisms. It is presently used in the Netherlands as a management tool for farmers and technical consultants, as a tool for monitoring the environmental performance of farmers, as a tool for setting standards for ecolabels and as a policy evaluation tool.  相似文献   
32.
四川林业产业统计监测制度研究   总被引:1,自引:0,他引:1  
本文讨论了四川省建立林业产业统计监测制度的必要性和林业产业统计指标体系的建立;确立了统计范围和统计报表的构成;提出了统计数据的收集方法。  相似文献   
33.
The presented paper analyses the relations between four features of geomorphology, i.e. aspect, slope, elevation and type of terrain, and tree layer diversity of forest ecosystems. The forest stand diversity is quantified by nine species diversity indices (N0, R1, R2, H, N1, N2, E1, E3, E5). The data used in this study come from the regional forest inventory of the Forest School Enterprise, Technical University Zvolen, Slovakia. Within this inventory, 26 permanent tracts were established in the systematic grid of 2×2 km, whereby a total of 120 sample plots were created on which 1,728 trees were measured. Analyses showed that species diversity is closely related only to elevation. However, the relationships of the individual species diversity indices to elevation are loose since the correlation coefficients do not exceed values of 0.30–0.40. The second part of this work presents spatial interpolation of species diversity degrees on a regional level using geostatistical methods. For this regionalisation, we used an indicator kriging. The final kriging map was found to be a suitable tool for the interpretation of tree species diversity over the investigated area.  相似文献   
34.
科技进步评价指标体系在科技进步评价中发挥越来越重要的作用,本文对河南省林业科技进步评价指标体系的建立和应用等方面进行了探讨。  相似文献   
35.
Dead wood in European beech (Fagus sylvatica) forest reserves   总被引:10,自引:0,他引:10  
Data were analysed on the volume of dead wood in 86 beech forest reserves, covering most of the range of European beech forests. The mean volume was 130 m3/ha and the variation among reserves was high, ranging from almost nil to 550 m3/ha. The volume depended significantly on forest type, age since reserve establishment and volume of living wood. More dead wood was found in montane (rather than lowland/submontane) reserves, longer-established reserves (time since designation) and reserves with higher volumes of living wood.

On average, fallen dead wood contributed more to the total dead wood volume than standing dead wood. The percentage of dead wood that was standing was almost twice as high in montane than in lowland/submontane forest reserves (45% versus 25%). The volume of dead wood at selected sites changed considerably over time. The fluctuations were significantly higher in lowland/submontane than montane reserves, possibly connected with differences in the disturbance regimes and especially damage caused by windstorms. In NW Europe, the blow down of formerly managed, even-aged stands led to extraordinary high volumes of dead wood shortly after reserve establishment.

The implications for forest management and biodiversity conservation are discussed. An increase in dead wood volumes must be carried out in accordance with the local/regional forest type and disturbance regime. Thus, in order to fulfil the requirements of as many wood-depending organisms as possible, it is important to preserve not only larger amounts of dead wood, but also dead wood of different types and dimensions as well as securing a long-term continuity of dead wood.  相似文献   

36.
介绍了森林可持续经营的标准和指标,对其重点和意义做了概述。  相似文献   
37.
森林经营可持续性评价方法   总被引:9,自引:0,他引:9  
森林经营可持续性评价是当前森林可持续经营研究和实施中亟待解决的一个难题。本文就森林经营可持续性评价指标的筛选、指标的无量纲化、指标权重的确定和可持续性水平综合评价等方法进行了探讨。  相似文献   
38.
三年分期播种试验结果,结合水分等其它试验数据,通过统计分析,得出栽培蓖麻从播种至成熟中各发育阶段的单因子和复因子(光、温、水)与阶段发育天数间的关系方程,可用于发育期予报。并相应得出各发育阶段的温度下限指标。与此同时还建立了蓖麻籽实产量和产油量与气象因子的关系方程,可用于产量和产油量的估测。通过盆栽试验得到南麻幼苗冻害温度指标。  相似文献   
39.
Management, operation and maintenance services of about 1.7 million ha irrigation areas, constructed the scheme by State Hydraulic Works (DSI) were turned over to Water User Association (WUA) in Turkey. The number of the WUAs is 330 in Turkey for 2005. There is therefore an urgent need to study methods of measurement and evaluation of financial performance of WUA in order to improve the financial performance and raise the management level of WUA. This paper proposes 12 financial indicators in order to measure and evaluate the financial performance of WUAs. Based on the results in four irrigation schemes and WUAs in Great Menderes basin, Turkey, the methods of measurement and calculation of financial performance indicators selected, and difference factor value related to each indicator are presented. Several financial performance indicators and difference factor values varied widely 1999 to 2004. Therefore, these financial performance indicators should be carefully evaluated and monitored for financial sustainability of WUAs.  相似文献   
40.
广西鹿寨县土地开发潜力评价研究   总被引:6,自引:1,他引:6  
叶妙君  卢伟  周寅康 《土壤》2004,36(4):430-433,445
土地开发潜力评价是科学开展土地开发工作的基础,影响土地开发潜力的因素众多,目前还没有公认比较成熟的评价理论与方法。本文结合广西鹿寨县的实际情况,提出包括开发地区自然因素、社会经济因素和生态环境因素等 3 方面的 13 个指标在内的土地开发潜力评价指标体系,运用模糊综合评价模型,以乡镇为分级单元,在科学地定量评价土地开发潜力的基础上,对鹿寨县的土地开发潜力进行分级,为土地开发整理工作提供了可靠的判断依据。同时,文章对该指标体系的实用性、可操作性进行了探讨。最后,对合理开展鹿寨县的土地开发工作提出了对策和建议。  相似文献   
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