榆次区生态系统服务价值研究

以山西省榆次区为例,核算其生态服务价值,为实现可持续发展和生态环境保护提供科学依据。结果显示：2005年榆次区生态系统服务总价值为8.60×108元,每公顷价值为6 556元;林地价值最大,占总价值的34.78%,其次为耕地,占总价值的34.78%,二者合计占总价值的3/4;水面、园地、湿地价值分别占总价值的10.19%,8.09%和5.60%;荒地和牧草地的价值最小,分别占总价值的1.76%和1.75%。可见,榆次区林地生态系统保护具有重要意义。     

The hosts and potential geographic range of Dothistroma needle blight

Dothistroma needle blight, one of the most important foliar diseases of Pinus spp., is caused primarily by the fungus Dothistroma septosporum (Dorog.) Morelet, and to a lesser extent by Dothistroma pini Hulbary. The potential distribution and abundance of Dothistroma spp. was determined by (i) developing a process-oriented model of potential distribution of Dothistroma spp. from known locations, (ii) compiling a comprehensive list of susceptible host species from existing scientific literature and (iii) determining the distribution of susceptible hosts in areas predicted to be suitable for range expansion of Dothistroma spp. Using these three sources of information regions at risk were identified as those that were predicted to be suitable for range expansion by Dothistroma spp. and included significant areas of susceptible host species.     

Wildfire risk in the wildland–urban interface: A simulation study in northwestern Wisconsin

The rapid growth of housing in and near the wildland–urban interface (WUI) increases wildfire risk to lives and structures. To reduce fire risk, it is necessary to identify WUI housing areas that are more susceptible to wildfire. This is challenging, because wildfire patterns depend on fire behavior and spread, which in turn depend on ignition locations, weather conditions, the spatial arrangement of fuels, and topography. The goal of our study was to assess wildfire risk to a 60,000 ha WUI area in northwestern Wisconsin while accounting for all of these factors. We conducted 6000 simulations with two dynamic fire models: Fire Area Simulator (FARSITE) and Minimum Travel Time (MTT) in order to map the spatial pattern of burn probabilities. Simulations were run under normal and extreme weather conditions to assess the effect of weather on fire spread, burn probability, and risk to structures. The resulting burn probability maps were intersected with maps of structure locations and land cover types. The simulations revealed clear hotspots of wildfire activity and a large range of wildfire risk to structures in the study area. As expected, the extreme weather conditions yielded higher burn probabilities over the entire landscape, as well as to different land cover classes and individual structures. Moreover, the spatial pattern of risk was significantly different between extreme and normal weather conditions. The results highlight the fact that extreme weather conditions not only produce higher fire risk than normal weather conditions, but also change the fine-scale locations of high risk areas in the landscape, which is of great importance for fire management in WUI areas. In addition, the choice of weather data may limit the potential for comparisons of risk maps for different areas and for extrapolating risk maps to future scenarios where weather conditions are unknown. Our approach to modeling wildfire risk to structures can aid fire risk reduction management activities by identifying areas with elevated wildfire risk and those most vulnerable under extreme weather conditions.     

杂交桉家系在桂北生长及优良性评价

[目的]对广西黄冕林场杂交桉的生长及优良性进行评价,找到更多适合在该区域今后推广种植的优良杂种材料.[方法]对3.5、5.8和8.5 a共3个年度的42个人工杂种家系、9个母本自由授粉家系和1个无性系试验林进行生长调查,开展不同林龄的干形、幼林枝瘿姬小蜂的受害率等的调查,利用方差分析和多性状综合坐标得分法进行分析,获得...     

北京地区林木损失额价值计量体系的应用说明

从研究理论的科学性与实际应用的可操作性相统一的角度出发,设计并研发《北京地区森林资源损失评估手册》,将其直接应用于不同森林类型林木损失额的计算,使得本项研究在具有科学性和合理性的同时,更具实际应用性和可操作性。文章对《手册》涉及的主要内容及功能、使用说明及流程、系统更新等进行了简要介绍。     

湖北省林业生态效益价值评估

笔者结合湖北林业资源特点,选取森林涵养水源、固土保肥、固碳释氧、改善环境、改善小气候、堤岸防护、农田防护、生物多样性保护、旅游休憩、湿地蓄水调洪、净化水质十大功能的15项指标,对湖北省林业生态效益价值(2009年度)进行了评估,评估结果表明:2009年湖北省林业生态效益总价值为4718.68亿元,其中森林生态效益价值为3476.51亿元,湿地生态效益价值为1242.17亿元。最后对评估结果进行了相关说明与分析,提出了关于评估工作的完善措施和提高湖北省林业生态效益的途径。     

基于业主视角的工程建设项目风险评估模型探讨

在工程实践中,承包商风险管理能力的高低将直接影响着工程风险的高低,作为业主在进行风险评估时不应忽略承包商风险管理能力对风险高低的影响。为此提出承包商风险管理能力指数概念,并构建基于风险自然属性评估和风险管理能力评估相结合的工程项目风险综合评估模型,以完善和充实风险等级评估的内涵。     

生态脆弱区重大建设项目的生态风险及其预控管理研究

为缩小区域发展差异,加快盆周山区和少数民族地区的发展,未来五年四川省将陆续在盆周山区和少数民族地区实施一批重大建设项目与资源开发项目。由于这一区域是四川乃至全国生态环境脆弱区,项目建设所引发的各类生态风险问题应引起高度重视。本文从重大项目的自然地理区位视角入手,分析加强项目生态风险管理的重大意义与项目实施可能面临的三大风险与四大成因,提出加强项目生态风险预控管理的五大对策建议。     

基于绿视率的城市绿化评估——以武汉江汉区为例

目前我国仍以3大传统绿化指标评估城市绿化的二维情况,缺乏三维空间绿化效果评估。文章以武汉市江汉区为例,采用系统抽样法,将江汉区划分为472个250m×250m网格,基于腾讯地图的街景图像计算绿视率,从江汉区绿视率整体空间格局、不同用地类型绿视率差异性以及绿化覆盖率对绿视率的影响等方面评估该片区的三维绿化,结果显示:1)江汉区不同区域绿视率差异较大,平均值为16.26%;2)公园绿地、居住用地、商业用地的绿视率依次递减;3)绿视率随绿化覆盖率的增加而增加,但其增长趋势逐渐趋缓。