Environmental Change and the Sustainability of European Forests

Summary

It is some years now since forest decline was a major public concern in Europe and was one of the principal environmental issues around which international research programs were focused. A number of internationally coordinated activities were initiated in the 1980s and 1990s and have continued until now; these contributed significantly to our current understanding of forestry and to the way in which forestry policies have developed. In short, the concept of sustainable development has had an increasing influence and is now of immeasurable value in forest policy, with sustainable forest management well established as its guiding principle. This sequence of events is examined here. The extent to which understanding has advanced is remarkable; much has changed. Arguably this period gave the first indication of the extent to which forests and ecosystems globally are threatened by environmental change. On the basis of the last 20 years, it is tempting to conclude that we now have an effective institutional framework and have made excellent progress. However, some of the recorded ecosystem responses seem anomalous; there are surprises in system responses, e.g., the linkage between sulphur and nitrogen depositions and forest growth. Even more importantly some specific pollutant problems remain and will intensify, and climate change has become an environmental issue of overwhelming importance.     

甘肃多儿国家级自然保护区维管植物区系分析

基于野外实地考察、植物标本的采集与鉴定以及结合文献研究的方法,分析了多儿保护区维管植物区系的物种组成和分布区类型。结果表明,该区维管植物共115科469属1323种,包括蕨类植物14科25属61种,裸子植物4科8属25种,被子植物97科436属1237种。多儿保护区维管植物区系优势现象明显,≥20种的优势科共879种,占该区维管植物总种数的66.44%;小属和单种属成分比例较大,占该区维管植物总属数的95.31%,总种数的75.51%。科级水平上,热带科（30.43%）稍多于温带科（26.96%）;属级水平上,温带科（72.49%）明显高于热带科（13.01%）;种级水平上,中国特有种有545种,其中538种与周边省份所共有,体现了该区系明显的过渡性和交汇性。该保护区维管植物区系地理成分复杂多样,属的分布有15个分布型和5个变型,温带地理成分占绝对优势,尤其以北温带分布为主。该区珍稀濒危野生植物较多,被列入保护名录有37种;一些古老、孑遗植物在该保护区具有良好的原始类群分布。本研究进一步完善了多儿保护区维管植物区系特征,为以后了解该保护区生物多样性提供可靠依据。     

我国猕猴桃细菌性溃疡病研究分析及防控

【目的】为了明确猕猴桃细菌性溃疡病的研究动态和进展,为该病的研究和防治提供参考。【方法】对1988-2015年期间中国知网中国期刊全文数据库上的猕猴桃细菌性溃疡病文献进行了统计分析。【结果】结果表明：我国猕猴桃细菌性溃疡病逐年加重,各猕猴桃产区发生不均衡;从文献研究内容上看,对猕猴桃细菌性溃疡病的防治和药剂筛选试验等内容较多,对病害的基础性研究以及规律、预测预报等方面研究较少。【结论】本文在详细分析文献的基础上提出了猕猴桃细菌性溃疡病的防控建议。     

基于WebGIS的森林旅游信息管理网站的构建

文章分析了旅游网站的现状、森林旅游的特点,介绍了基于WebGIS技术开发森林旅游信息管理网站的优势和系统设计方法。通过森林旅游网站的构建实现面向公众的森林旅游信息交流和面向管理部门的信息管理功能。     

浙江龙泉地区珍贵阔叶树种保护培育工作现状及对策

为了促进人与自然和谐相处,保障生态文明建设,应做好森林资源保护培育工作。通过分析浙江龙泉地区珍贵阔叶树种保护培育工作的现状及问题,提出相应的对策,以完善龙泉地区森林资源建设,促进林业可持续发展。     

Exploring tree diversity and stand structure of savanna woodlands in southeastern Sudan

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots (1000 m² for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height (DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species (Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm² and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.     

凤阳山不同林分土壤腐殖质特征及影响因素

以浙江省凤阳山海拔1 300~1 400 m处不同林分类型(阔叶混交林、针阔混交林、杉木林、竹林)为对象,测定不同土层土壤基本理化性质、酶活性及腐殖质质量分数,分析土壤腐殖质特征及影响因素,为凤阳山自然保护区的土壤肥力和可持续经营发展提供理论依据。结果表明:土壤腐殖质质量分数针阔混交林最高,阔叶混交林、竹林、杉木林次之;胡敏酸质量分数针阔混交林最高,杉木林最低;富里酸质量分数针阔混交林最高,竹林最低。除磷酸酶活性随土层加深无统一规律外,4种林分脲酶活性、过氧化氢酶活性及蔗糖酶活性土壤随土层加深皆呈现降低趋势。土壤pH值、土壤密度与土壤腐殖质质量分数、胡敏酸质量分数和富里酸质量分数均呈现显著的负相关;除磷酸酶活性相关性不显著外,土壤脲酶活性、蔗糖酶活性、过氧化氢酶活性、总孔隙度、毛管孔隙、非毛管孔隙与土壤腐殖质质量分数、胡敏酸质量分数和富里酸质量分数均呈现显著的正相关。凤阳山不同林分类型对土壤腐殖质特征的影响较土层深度更显著,土壤理化性质及酶活性与土壤腐殖质质量分数有着密切关系。     

运用植被指数时序特征对落叶松人工林分类

为探究植被指数时序特征是否有利于落叶松人工林提取,以孟家岗林场为研究试验区域,根据落叶松人工林季相和物候特征,利用Landsat8OLI影像数据提取研究区内5种植被的归一化植被指数(I NDV)、差值植被指数(I DV)、比值植被指数(I RV)、增强型植被指数(I EV),构建相应的植被指数时序特征。采用最大似然和随机森林两种方法对单一时相影像和加入植被指数时序特征的影像进行对比试验。结果表明:影像中加入植被指数时序特征后,最大似然算法的分类总体精度为89.53%,Kappa系数为0.87,比单一时序特征的影像分类精度提高了13.35%;随机森林算法的森林类型分类总体精度为93.22%,Kappa系数为0.92,比单一时序特征的影像分类精度提高了19.8%。因此,加入植被指数时序特征后能得到更高的落叶松人工林提取精度。     

周晓平(宁化县县属国有林场,福建,宁化365400)

近些年来宁化县非常注重高质量、高品位绿色发展要求,保护好绿水青山才能成就金山银山的经营理念不断向纵深推进,人们对乡土树种越来越倍加珍惜,因此急需加快乡土树种栽培与保护。本文从乡土树种林业内涵展开分析,阐述了乡土树种在宁化县生态恢复过程中的作用,主要从乡土树种具有生长快_^[1]、适应性强、病虫害少、用途多、改良土壤性强、森林植物群落多样性丰富、林分生产力强、再生繁衍能力强等方面深入探索,从而证明了乡土树种在树种优选方面的重要作用。     

北海镜心斋园林意象分析

清代皇家园林北海镜心斋规模虽然不大,独具匠心的设计,使该园呈现出丰富的审美意象。通过对该园的相关视觉图式和环境认知的分析以及与实际园林处理的相互印证,探讨了镜心斋的设计思路与手段,有助于理解视觉语言和整体意象在深化园林设计中起到的关键作用。