海拔和坡向对色季拉山高山杜鹃凋落物分解的影响

为探究高寒森林凋落物在不同海拔和坡向的分解动态,以西藏色季拉山的高山杜鹃（Rhododendron simsii）凋落物为研究对象,在色季拉山设置3 500、3 700、3 900、4 100 m等4个梯度海拔以及西北坡（阴坡）和东南坡（阳坡）2个坡向,开展为期2年的凋落物掩埋试验,采用Olson模型明晰凋落物的降解规律,并结合木质纤维素的质量损失和土壤理化性质探究影响凋落物分解的因素。结果表明：不同海拔和坡向凋落物质量残留率均随分解时间增加而下降,分解2年后不同海拔的质量残留率为36.65%～75.99%;凋落物分解速度基本呈阴坡大于阳坡的趋势,其中海拔3 700 m阳坡处分解速度最快、半衰期和周转期最短;木质纤维素的质量损失也基本呈阴坡大于阳坡的趋势,且木质素分解程度最大,对凋落物质量损失的贡献超过50%;土壤中碳氮磷钾营养元素含量主要受坡向和凋落物分解时间的影响,在不同海拔间差异较小;海拔、坡向、分解时间及其交互作用均对凋落物分解有显著影响（P<0.01）,土壤含水率和碳氮比也是影响凋落物分解的重要因素。本研究可为高寒森林凋落物分解规律及影响因素提供理论依据。     

基于GIS和空间自相关模型的南宁市林地空间变化研究

【目的】掌握南宁市林地时空分布的变化规律,为制定科学有效的林地管理措施提供基础数据。【方法】基于2008、2013、2018年3期南宁市森林资源调查数据,应用空间统计技术,结合转移矩阵及空间自相关模型,分析不同时期南宁市林地分布格局,探究林地时空分布动态变化特征及空间聚集规律。【结果】2008—2018年,南宁市天然林面积减少2.39×10⁴ hm²,人工林面积增加2.60×10⁴ hm²,其他林地面积减少2.98×10⁴ hm²,林地总面积略有减少;林地类型变化繁杂,天然林和其他林地主要转化为人工林,人工林主要转化为非林地,其中2013—2018年林地变化更为剧烈;天然林和人工林的分布均具有显著的空间自相关性,天然林的空间自相关性高于人工林。整个研究期间,天然林和人工林的空间聚集性均呈下降趋势。【结论】2008—2018年南宁市林地发生较大的转移及变化,为有效保护林地、实现森林资源的可持续发展,需进一步加强实施科学有效的林地资源保护政策和措施。     

广东省第三期沿海防护林体系建设

分析广东省沿海防护林体系建设历程及第三期建设的必要性,其体系由沿海基干林带和纵深防护林构成,基干林带是沿海防护林体系的主体,建设类型包括红树林恢复造林、基干林带人工造林、灾损基干林带修复和老化基干林带更新、困难立地造林和退塘造林;纵深防护林对进一步防御和减轻登陆台风、台风引起的暴雨和泥石流等危害具重要作用,建设类型包括...     

宽甸地区林业资源及其特色产业发展研究

综述宽甸地区自然条件和林业资源概况,介绍林业特色产业的规划布局和建设现状.基于生态文明的发展理念,根据林业资源的特点和优势,提出进一步发展特色林业产业的可行性建议,为充分发挥宽甸地区林业资源潜力提供借鉴.     

长沙市城市森林健康调控试验及初步结果

以长沙市王陵公园为试验点,开展城市森林健康调控试验,采用害虫综合调控方法,运用生物天敌调控、生物药剂控制、物理防治等方法对该公园内的主要森林害虫,如马尾松毛虫,白蚁科、金龟子科、夜蛾科、天蛾科等的害虫,降低了虫口密度,保持了林分内的生态平衡,为城市森林健康的维护提供了新的综合途径。     

Stable carbon and nitrogen isotopic evidence for ecotonal coupling between boreal forests and fishes

Abstract— As a result of water turbulence effects on boundary layer diffusion resistance and carbon isotopic discrimination, the δ¹³C values (ratios of ¹³C: ¹²C) of attached algae may often overlap those of terrestrial plants, thereby making it impossible to distinguish between the relative importance of these two potential food sources for aquatic animals. The present study used a dual isotope approach (δ¹³C and δ¹⁵N) to refine measurements of the incorporation of allochthonous organic matter into freshwater fishes. The dependence of five species of littoral fishes on terrestrial detritus for part of their energy sustenance was demonstrated. The littoral zones of boreal Canadian Shield lakes are, therefore, not isolated from their surrounding riparian forests in terms of carbon flow as present day timber management guidelines erroneously assume, but instead exhibit a measurable degree of ecotonal land-water coupling. As a result, clearcut logging of riparian forests to the lakeshore edge, permissible by law in most Canadian provinces containing boreal forests, may have to be reassessed as a forest harvesting strategy.     

云南宝台山国家森林公园森林资源现状分析

为掌握云南宝台山国家森林公园的森林资源特点,并为制定森林公园的森林资源保护与利用规划提供依据,对该公园2019年森林资源监测数据进行了分析.结果 表明:该森林公园林地面积占公园总面积的99.4％,森林覆盖率高达90.50％.林地以有林地为主,面积占比为90.9％.森林起源以天然为主,面积占比为77.8％;人工起源为辅....     

Logging pattern and landscape changes over the last century at the boreal and deciduous forest transition in Eastern Canada

Forestry practices associated with the industrial era (since ~1900) have altered the natural disturbance regimes and greatly impacted the world’s forests. We quantified twentieth century logging patterns and regional scale consequences in three sub-boreal forest landscapes of Eastern Canada (117,000, 49,400 and 92,300 ha), comparing forestry maps depicting age and forest cover types for early industrial (1930) and present-day (2000) conditions. Results were similar for the three landscapes, indicating large-scale forest change during the twentieth century. In 1930, previous logging activities had been concentrated in the lowlands and along the main hydrographical network, as compared to a more even distribution over the landscapes in 2000, reflecting a decreasing influence of the environmental constraints on forest harvesting. In 1930, old-aged forests (>100 years) accounted for more than 75% of the unlogged areas of the three landscapes, as compared to less than 15% for the present-day conditions. Logging practices have thus inverted the stand age distribution of the landscapes that are currently dominated by young and regenerating stands. The 1930 forest cover types showed a clear relationship with elevation, with conifers located in the lowlands and mixed and deciduous stands restricted to the upper slopes. Between 1930 and 2000, 58–64% of the conifer areas transformed to mixed and deciduous forests, such that no clear altitudinal relationships remained in 2000. We conclude that twentieth century logging practices have strongly altered the preindustrial vegetation patterns in our study area, to the point that ecosystem-based management strategies should be developed to restore conifer dominance, altitudinal gradients, as well as the irregular structure inspired from old forest stands.     

酵素剂SS-200在菠菜和黄瓜上的施用效果研究

在保护地栽培,高肥力土壤条件下,研究施用天然复合酵素剂SS-200对菠菜、黄瓜生长发育、产量和品质的影响。结果表明:与常规施用化学肥料相比,施用天然复合酵素剂SS-200,有利于菠菜、黄瓜上的生长发育,其叶片数,茎粗,株高都有显著增加;施用天然复合酵素剂SS-200增加了菠菜产量,增产达到24.5%,也提高黄瓜的果实产量,平均1 hm2可以增产13.9%;同时施用SS-200菠菜叶柄中的硝酸盐含量降低了700 mg/L,达到9.2%,而SS-200对黄瓜的可溶性糖和Vc含量影响不大;由于肥料投入的降低及产量的增加,1 hm2菠菜的利润达到55 284元/hm2,黄瓜的利润也达到了67 082元/hm2。     

柑橘天然杂种秭归橘橙来源探究

秭归橘橙为天然柑橘杂种,果实无核、早熟,但其亲本来源未得到深入的分析和验证。为探明秭归橘橙的亲本,应用倍性检测、形态学标记和AFLP、cpSSR、nSSR等分子标记,对其进行遗传鉴定。倍性检测证实秭归橘橙为二倍体,叶形指数、气孔密度和大小、花粉育性和花粉形态分析表明秭归橘橙形态特征上偏向于甜橙,而其花粉染色活力介于甜橙与红橘之间。AFLP聚类分析表明秭归橘橙介于橙和橘之间。cpSSR、nSSR确认秭归橘橙的母本为甜橙(Citrus sinensis[L.]Osbeck),父本为橘类(C.reticulate Blanco)。