不同管理枣林枣粘虫(Ancylis sativa)天敌功能团的组成及动态

枣粘虫(Ancylis sativa)是枣树主要的食叶和蛀果害虫,为了控制其危害,2004年在太谷地区对4种不同处理枣林的枣粘虫天敌发生与态势进行了系统的调查研究,结果表明种草综合防治枣林枣粘虫天敌昆虫的物种数比种草常规防治枣林、未种草综合防治枣林和未种草常规防治枣林分别增加37.2%、84.4%和118.5不%,个体数分别增加39.2%、91.0%和187.4%,枣粘虫幼虫和蛹的寄生率分别增加46.94%和31.27%、35.21%和21.99%、116.42%和60.33%;综合防治枣林区草蛉类和寄生性天敌类的丰盛度明显大于(P<0.05)化学防治的枣林,而瓢虫类与蜘蛛类则明显小于(P<0.05)化学防治的枣林,食虫蝽类与其它捕食性天敌则是种草枣林区大于未种草枣林区;枣林种草后天敌的恢复与重建速率提高了50%~81%;种草枣林多样性的标准误明显减小,相关性测定表明枣粘虫天敌功能团与物种的优势度、多样性、均匀度的变化趋势较为一致,均极显著(P<001)相关。     

Assessing the conservation value of a human-dominated island landscape: Plant diversity in Hawaii

The conversion of native habitats to pasture and other working lands, unbuilt lands modified by humans for production, is one of the greatest threats to biodiversity. While some human-dominated landscapes on continents support relatively high native biodiversity, this capacity is little studied in oceanic island systems characterized by high endemism and vulnerability to invasion. Using Hawaii as a case study, we assessed the conservation value of working landscapes on an oceanic island by surveying native and non-native plant diversity in mature native forest and in the three dominant land covers/uses to which it has been converted: native, Acacia koa timber plantations, wooded pasture, and open pasture. As expected, native plant diversity (richness and abundance) was significantly higher and non-native abundance significantly lower in mature native forests than any other site type. A. koa plantations and wooded pasture supported four and three times greater, respectively, species richness of native understory plants than open pasture. Also, A. koa plantations and wooded pasture supported similar species communities with about 75% species in common. Conservation and restoration of mature native forest in Hawaii is essential for the protection of native, rare species and limiting the spread of non-native species. A. koa plantations and wooded pasture, however, may help harmonize production and conservation by supporting livelihoods, more biodiversity than open pasture, and some connectivity between native forest remnants important for sustaining landscape-level conservation value into the future.     

Changes in understorey plant species richness following logging and prescribed burning in shrubby dry sclerophyll forests of south‐eastern Australia

Abstract The impacts of prescribed burning and timber harvesting on species diversity have been the subject of considerable debate. The temporal and spatial scale of these disturbances often presents major limitations to many studies. Here we present the medium‐term results of a planned long‐term study examining the impacts of logging and prescribed burning on the understorey floristic richness in shrubby dry sclerophyll forest in the south‐east of New South Wales, Australia. Generalized estimating equations were used to model the effect of environmental factors and disturbance variables on species richness at the coupe (～30 ha) and plot (～0.01 ha) scale. At the plot scale, fire effects on separate components of the vegetation were broadly consistent with other studies, with frequent fire resulting in a relative increase of species richness for species less than 1 m in height and a decline of larger species taller than this height. At the coupe scale, there was no decline in richness of larger shrub species, possibly owing to the spatial heterogeneity of fire frequency at this scale. Logging resulted in significantly greater species richness in the shrub layer, but had no significant effect on species richness in the ground layer. During the study period, there was a general decline in plant species richness at both coupe and plot scales which occurred independently of imposed management regimes. This is thought to be related to a natural succession following wildfire, and may be due to the absence of high‐intensity fire in the study area since 1973, or to an effect related to season of burning.     

西藏森林植被乔木层碳储量与碳密度估算

利用第八次森林资源连续清查数据和不同树种的树干密度、含碳率等参数,运用生物量清单法,估算了西藏自治区森林乔木层植被碳储量和碳密度.结果表明: 西藏森林生态系统乔木层植被总碳储量为1.067×10⁹ t,平均碳密度为72.49 t·hm^-2.不同林分乔木层碳储量依次为:乔木林>散生木>疏林>四旁树.不同林种乔木层碳储量大小依次为:防护林>特殊用途林>用材林>薪炭林,其中前两者所占比例为88.5%;不同林种乔木层平均碳密度为88.09 t·hm^-2.不同林组乔木层碳储量与其分布面积排序一致,依次为:成熟林>过熟林>近熟林>中龄林>幼龄林.其中,成熟林乔木层碳储量占不同林组乔木层总碳储量的50%,并且不同林组乔木层碳储量随着林龄的增加呈先上升后下降的趋势.     

澳大利亚输华农林产品口岸有害生物截获概况

【目的】口岸截获有害生物的数据分析可为进境农林产品检疫监管提供依据。【方法】对澳大利亚自2010至2015年输华农林产品及其入境口岸有害生物截获情况做综合分析。【结果】2010—2015年从澳大利亚输华农林产品货物中截获各类检疫性有害生物115种。其中,粮谷中以截获的杂草种类和截获频次最多,分别达到59种和31801批次;木材及木制品中以截获的蠹虫最多,达43种,共2456批次;从水果和种苗中截获病原菌6种,共79批次。另外,从入境旅客携带物中共截获检疫性有害生物9种,共66批次。【结论】澳大利亚输华农林产品可携带的检疫性有害生物自口岸传入的风险较高,相关部门应加强口岸检疫工作。     

集体林区实施天保工程的对策和建议

 由于集体林区经济结构单一,长期以来在木材生产方面的高税费政策,造成地方财政和林业发展对木材生产的依赖,实施天保工程使集体林区的经济发展面临挑战。为了既达到降低森林资源消耗,扩大造林规模的目的,又减轻林区财政增收、农民脱贫、林业自身建设乃至社会文化发展方面的压力,必须调整林业税费政策、落实中央补助资金。同时,在地方政府的组织领导下,改变农村能源结构、建设现代林业体系。     

生物技术在林业中的应用及其影响

现代生物技术正在被越来越多地应用到林业研究和生产中,并将对林业的发展产生深远的影响。本文总结了目前在林业中应用和正在发展的生物技术,探讨了与使用这些技术有关的主要问题及争论,强调了科学地评价这些技术,以及在社会可接受的范围内进行决策的重要性。最后,本文简要指出了将来生物技术研究和应用的方向,并说明了政府应该在何种程度上帮助生物技术的发展及调节它的应用。     

城市林业概述与发展趋势

随着社会经济的快速发展和城市化进程的加快,城市环境问题日益成为社会各界关注的焦点,城市林业在城市建设与发展中的地位和作用越来越受到重视。从自然属性与社会属性,地域范围与层次的角度介绍了城市林业的基本概念和内涵,并比较了城市林业与传统林业、现代园林在属性、经营管理和功能方面的差别。借助已有的研究数据和成果,阐述了城市林业在城市发展中的作用,提出了现代城市林业面临的机遇和挑战以及未来发展趋势。     

广东省珠江三角洲城市森林抗火树种筛选研究

在广东省珠江三角洲地区(火烧迹地和污染区、公园、风景区、村旁风景林等不同类型区林地)进行城市林业抗火树种的筛选研究,对所调查的52个树种进行含水率、粗脂肪含量、粗灰分含量以及对其中的6个树种的燃烧热值作了测定。结果表明：同时满足含水率≥40％、粗脂肪含量≤20‰以及粗灰分含量≥5％三个条件的有16个树种(铁冬青、假苹婆、细叶榕、腺叶野樱、红桂木、多花山竹子、半枫荷、牛矢果、朴树、秋枫、白颜、枫香、麻楝、阿丁枫、蝴蝶果、吊瓜木),可初步肯定这些树种具有较高的抗火性。其中白颜树、枫香、秋枫、麻楝、吊瓜木、蝴蝶果6个树种的燃烧热值比较低,均比木荷低,具有较高的抗火性,可作为城市林业生物防火推荐树种。