Agroforestry systems and soil surface management of a tropical alfisol:

Field runoff plots, 70 x 10 m each, were established on a tropical Alifisol in southwestern Nigeria to monitor water runoff, soil erosion and nutrient loss in water runoff. The non-agroforestry control treatment (A) was established at two levels: plow-till and no-till systems of seedbed preparation. There were two agroforestry systems based on contour hedgerows of (B) Leucaena leucocephala and (C) Gliricidia sepium established at 4-m and 2-m spacings. Field plots were established in 1982 and hydrological measurements were made for uniform maize-cowpea rotation for 12 consecutive growing seasons from 1982 through 1987. Once established hedgerows of Leucaena at 2-m spacing were extremely effective in reducing water runoff and controlling erosion. Runoff, erosion and nutrient losses were generally more from maize grown in the first season than from cowpea grown in the second. Mean seasonal erosion from maize was 4.3, 0.10, 0.57, 0.10, 0.64 and 0.60 t/ha for plow-till, no-till, Leucaena-4m, Leucaena-2m, Gliricidia-2m treatments, respectively. Mean runoff in the first season from treatments listed in the order above was 17.0, 1.3, 4.9, 3.3, 4.3, and 2.4 percent of the rainfall received. There were high losses of Ca and K in water runoff from the plow-till treatment. In contrast to runoff and erosion, losses of bases in water runoff from agroforestry treatments were relatively high, high concentration of bases in runoff was probably due to nutrient recycling by the deep-rooted perennials.     

Risk management: A probe and study on forest fires

The subject of risk management is attracting more and more attention around the world. The risk of forest fire disasters should be faced and dealt with for forest fires cannot be avoided. Treating forest fire disasters as a risk management issue promotes important measures and methods for fire fighters to prevent, reduce and control the risks of forest fires. In this paper, the risk concept and risk connotation as well as the management risks for forest fire suppression are discussed clearly. Issues such as risk judgments, risk analysis, risk control and the assessment of risk, including their contents and corresponding methods are clarified. Translated from Forest Resources Management, 2006, 2: 24–27 [译自: 林业资源맜理]     

Linking wolves to willows via risk-sensitive foraging by ungulates in the northern Yellowstone ecosystem

After an absence of approximately 70 years, gray wolves (Canis lupus) were re-introduced into Yellowstone National Park in the mid-1990s. We studied the potential influence of wolf/ungulate interactions upon willow (Salix spp.) growth in the valleys of the Gallatin and Lamar Rivers, as well as Slough and Soda Butte Creeks, in the northern Yellowstone ecosystem. When we compared willow heights from photographs taken prior to 1998 (willows <2 m tall) with those taken in 2004, we found an increase in willow height for 22 of 42 sites within the study area. Based on comparisons of the chronosequence photos, since wolf introduction none of the 16 upland riparian sites showed an increase in willow height, while 22 of 26 of the valley-bottom riparian sites had willow height increases. In 2004, willow height exhibited a strong inverse relationship with the percentage of browsed stems (r = −0.81, p < 0.01, n = 42). Results of regressions for valley-bottom sites indicated that view distance, impediment distance, and the number of bison (Bison bison) flops were inversely related to willow height (p ≤ 0.02). Increased willow heights were not significantly (p = 0.18) related to patterns of moisture availability. Willow height increases documented in this study appear to have been at least partially due to behaviorally mediated trophic cascades involving wolves and ungulates, via a mechanism of predation risk. While willow release (i.e., increased height growth) within the study area is in a very early stage, results suggest potentially important indirect effects of a top carnivore in a terrestrial food chain that may aid in the restoration of riparian species and the preservation of biodiversity.     

硫酸盐草浆黑液制粉状活性炭的研究

本文探讨硫酸盐草浆纸厂黑液的治理和利用,提出用酸化法从黑液中沉析木素制取粉状活性炭。大约生产10t草浆可制取1t优质粉状活性炭。同时还含有占总碱量24%的Na_2S可回收。排出的废液即使不再经过处理,其污染程度也已大大降低。     

A mangrove stand under sewage pollution stress: Red Sea

A mangrove stand of Avicennia marina located at the South Corniche of Jeddah city receives about 100 000 m³ of sewage per day. The sewage has high values of BOD, COD, nutrient concentrations, heavy metals and faecal coliform counts.The mangrove stand is very small and occupies an area of about 0.45 km². The trees are stunted with low pneumatophore density. The pneumatophore distribution is restricted to the area of substrate underneath the plant crown covers and they do not look healthy. A high proportion of them was observed to be dead and/or aberrant. These abnormal induced features were attributed to the sewage discharge in the area. The death of pneumatophores decreases the aeration area which apparently affects the respiration rate of the root system, nutrient uptake and plant growth, consequently leading to a retarded growth of the mangroves.     

Wolves, elk, willows, and trophic cascades in the upper Gallatin Range of Southwestern Montana, USA

We summarized the status of wolves (Canis lupus), elk (Cervis elaphus), and woody browse conditions during the 20th century for the upper Gallatin elk winter range in southwestern Montana, USA. During this period, wolves were present until about the mid-1920s, absent for seven decades, and then returned to the basin in 1996. A chronosequence of photographs, historical reports, and studies indicated willows (Salix spp.) along streams became heavily browsed and eventually suppressed following the removal of wolves, apparently due to unimpeded browsing by elk. However, after wolf establishment in 1996, browsing intensity on willows lessened in some areas and we hypothesized that, at both a landscape and fine scale, browsing pressure reflects terrain configurations influencing predation risk (nonlethal effects), in conjunction with lower elk densities (lethal effects). We measured browsing intensity and heights of Booth willow (S. boothii) along 3000 m reaches of the Gallatin River and a tributary to examine the potential influence of wolf/elk interactions upon willow growth. Where the Gallatin Valley is relatively narrow (high predation risk), willows began releasing in 1999 and by 2002 were relatively tall (150–250 cm). In contrast, willow heights along a wider portion of the Gallatin Valley, along the open landscape of the tributary, and an upland site (all low predation risk) generally remained low (<80 cm). We identified terrain and other features that may contribute to the perceived risk of wolf predation, by elk for a given site. Although alternative mechanisms are discussed, changes in willow communities over time following wolf removal and their subsequent reintroduction were consistent with a top-down trophic cascade model involving nonlethal and possibly lethal effects. If similar top-down effects upon vegetation hold true in other regions of North America and other parts of the world where wolves have been extirpated, wolf recovery may represent a management option for helping to restore riparian plant communities and conserve biodiversity.     

张家口市区环境空气质量现状及其发展对策初探

空气质量状况如何，不仅影响到人们的生活质量，同时也影响到当地经济的发展。为了更进一步探讨张家口市区环境质量状况及其发展，从市环保局监测站了解到，张家口市区空气质量污染程度严重，主要污染物是降尘、总悬浮颗粒物及燃煤、化工企业及车辆排放的有毒有害气体。因此，要达到城市环境的可持续发展，就必须加强生态建设，搞好城市绿化，从根本上改善空气质量。     

蒙特卡罗在项目融资风险评估中的应用

项目融资具有强大的筹资能力，在我国的应用具有广阔的前景。但项目融资也存在巨大的风险，需要对风险加以管理．风险评估是风险管理的重要步骤。本文通过介绍蒙特卡罗的基木概念、基本原理和工作程序，采用蒙特卡罗模拟与Matlab程序相结合的方法进行了项目融资风险定量评估，并结合实例对此方法予以说明。     

Studies on Heavy Metal Pollution in Soil—Plant System：A Review

Heavy metal pollution in soil-plant system is of major environmental concern on a world scale and in China in particular with the rapid development of industry.The heavy metal pollution status in soil-plant system in China,the research progress on the bioavailability of heavy metals (effecting factors,extraction methods,free-ion activity model,adsorption model,multivariate regression model,Q-I relationship,and compound pollution),and soil remediation are reviewed in paper.Future research and monitoring is also discussed.     

排污权交易:一种基于市场的环境控制制度

排污权交易是一种基于市场的环境污染间接控制制度。微观上,排污权的交易有利于企业以最小的成本费用解决排污问题和提高企业投资污染控制设施的积极性;宏观上,排污权的交易有利于降低整个社会控制环境总成本和实现资源优化配置。有赖于市场机制的排污权交易制度的实施需要一定的前提和条件。