Incentive mechanisms to enforce sustainable forest exploitation

Using a two-player differential game approach, this paper deals with the issue of tropical deforestation. The assumption is that developing forestry countries (called the South) do not, or cannot, necessarily have the same utility for forest conservation than the developed countries (called the North). Given the global nature of the problem, we assume that it may be wise that the North offers financial support to the South to help in achieving a sustainable forest policy. We derive sustainable and short-run deforestation policies and provide a transfer mechanism which insures that the South will indeed implement the sustainable one.     

Assessment of spatial variability in some soil properties as related to soil salinity and alkalinity in Bafra plain in northern Turkey

The objectives of this study were to assess the variability in soil properties affecting salinity and alkalinity, and to analyze spatial distribution patterns of salinity (EC) and alkalinity (ESP) in the plain, which was used irrigation agriculture with low quality waters. Soil samples were collected from 0–30cm, 30–60cm, 60–90cm and 90–120cm soil depths at 60 sampling sites. Soil pH had the minimum variability, and hydraulic conductivity (Ks) had the maximum variability at all depths. The mean values of pH, EC, ESP and Ks increased while the mean values of CEC decreased with soil depth. Values pH, EC and ESP were generally high in the east and northeastern sides. Soil properties indicated moderate to strong spatial dependence. ESP and pH were moderately spatially dependent for three of the four depths, EC exhibited moderate spatial dependence for one of the four depths, CEC had a moderate spatial dependence at all depths, and Ks exhibited a strong spatial dependence. EC, CEC, and ESP were considerably variable in small distances. The spatial variability in small distances of EC, CEC, pH and ESP generally increased with depth. All geostatistical range values were greater than 1230m. It was inferred that the strong spatial dependency of soil properties would be resulted in extrinsic factors such as ground water level, drainage, irrigation systems and microtopography.     

动态因子分析在环境监测数据综合处理中的应用

动态因子分析(DFA)作为降维度的多元统计方法,被设计用于时间序列分析,以揭示多元变量中解释变量与共同趋势对响应变量的影响程度。相较传统多元统计方法,DFA显性考虑时间因素,并量化影响响应变量的潜在因素。该方法可以忽略内在理化过程,具有良好的模拟效果,且在国外已广泛应用于地表水及地下水生态环境、空气污染等领域,但在国内尚未被应用。DFA在自身完善、应用范围、信息挖掘、数据预处理、预测分析、空间分析方面仍有巨大发展前景。