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991.
基于RS林地退化监测技术 总被引:2,自引:0,他引:2
以永安市、连城县、漳平市为研究区域,选择林地土层厚度、林地土壤侵蚀、林地有机质、全氮、全磷、全钾、森林气候生产力、森林生产力等因子,应用层次分析法,构建林地退化评价指标体系。通过RS技术提取各指标专题信息,生成林地退化图。结果表明,研究区无退化林地面积289 204.20 hm2,轻度退化面积264 772.24hm2,中度退化面积142 851.71 hm2,严重退化面积60 473.69 hm2,剧烈退化面积139.99 hm2,分别占总面积的38.18%、34.96%、18.86%、7.98%、0.02%;3县(市)中永安市林地状况最好,漳平市次之,连城县最弱;研究区林地退化状况总体良好。 相似文献
992.
旅游区人为干扰对森林群落物种多样性的影响 总被引:6,自引:0,他引:6
研究人为干扰对湖北省梭布垭石林针阔混交林森林群落物种多样性的影响。结果表明,人为干扰对乔木层马尾松Pinus massoniana和杉木Cunninghamia lanceolata优势种的主体地位和作用没有根本性的改变,但使群落平均胸径(或地径)和平均树高降低,群落种类组成发生变化。重度干扰和中度干扰降低了群落乔木层阔叶树种和灌木层优势种的作用和地位,重要值降低,但增加了群落物种多样性水平。不同干扰类型的群落,在垂直高度1.0 m以下,Shannon-Weiner多样性指数较大,1.1 ~ 3.0 m高度达最大,以后随高度升高,多样性指数降低,在9.1 m以上的高度层,树种单一,多样性为0。图3表3参13 相似文献
993.
韩焕金 《农业图书情报学刊》2010,22(2):198-201
森林防火工作历来是党和国家很重视的。《森林防火》见证了我国森林防火工作的发展历程。对《森林防火》2001-2008年32期的载文量及各栏目载文量、文献标识码、载文作者群进行了统计分析,从而查找杂志的不足之处并提出改进方法,更好的为全国森林防火工作服务。 相似文献
994.
通过浅析"相持阶段林业"与谋划"南用"、"西治",采用化学除草、调控、优化林地植被,促进营林生产现代化,促进林业可持续发展。 相似文献
995.
紫叶加拿大紫荆组织培养研究 总被引:1,自引:0,他引:1
研究了外植体采集时间,不同质量浓度的6-BA、NAA、蔗糖以及不同部位茎段对紫叶加拿大紫荆增殖生长的影响,并初步研究了基本培养基I、BA、NAA对生根的影响。结果表明,紫叶加拿大紫荆外植体最佳的采集时期为5月;其增殖培养基为WPM+6-BA 1.5~2.5 mg/L+NAA 0.1 mg/L+蔗糖30 g/L,增殖系数最高达3.3;带愈伤组织的下部茎段的增殖效果好于不带愈伤组织上部茎段,上部茎段在高质量浓度的6-BA中增殖效果好;基本培养基、IBA质量浓度、NAA质量浓度对生根率有影响,最佳的配比是MS+IBA 5 mg/L+NAA 0.5 mg/L。 相似文献
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Restoring altered forest landscapes toward their ranges of natural variability (RNV) may enhance ecosystem sustainability and resiliency, but such efforts can be hampered by complex land ownership and management patterns. We evaluated restoration potential for southern-boreal forests in the ∼2.1 million ha Border Lakes Region of northern Minnesota (U.S.A.) and Ontario (Canada), where spatially distinct timber harvest and fire suppression histories have differentially altered forest conditions (composition, age–class distribution, and landscape structure) among major management areas, effectively resulting in forest landscape “bifurcation.” We used a forest landscape simulation model to evaluate potential for four hypothetical management and two natural disturbance scenarios to restore forest conditions and reduce bifurcation, including: (1) a current management scenario that simulated timber harvest and fire suppression practices among major landowners; (2) three restoration scenarios that simulated combinations of wildland fire use and cross-boundary timber harvest designed to emulate natural disturbance patterns; (3) a historical natural disturbance scenario that simulated pre-EuroAmerican settlement fire regimes and windthrow; and (4) a contemporary fire regime that simulated fire suppression, but no timber harvest. Forest composition and landscape structure for a 200-year model period were compared among scenarios, among major land management regions within scenarios, and to six RNV benchmarks. The current management scenario met only one RNV benchmark and did not move forest composition, age–class distribution, or landscape structures toward the RNV, and it increased forest landscape bifurcation between primarily timber-managed and wilderness areas. The historical natural disturbance scenario met five RNV benchmarks and the restoration scenarios as many as five, by generally restoring forest composition, age–class distributions, and landscape structures, and reducing bifurcation of forest conditions. The contemporary natural disturbance scenario met only one benchmark and generally created a forest landscape dominated by large patches of late-successional, fire-prone forests. Some forest types (e.g., white and red pine) declined in all scenarios, despite simulated restoration strategies. It may not be possible to achieve all objectives under a single management scenario, and complications, such as fire-risk, may limit strategies. However, our model suggests that timber harvest and fire regimes that emulate natural disturbance patterns can move forest landscapes toward the RNV. 相似文献
1000.
Impacts of resource extraction on forest structure and diversity in Bardia National Park,Nepal 总被引:1,自引:0,他引:1
Repeated biomass harvesting for human livelihood needs can cause significant changes in forest structure, composition and diversity. Such impacts have often been associated with the distance to villages and their size, but the effects of individual villages in relation to their characteristics have been little studied. Focussing on the issues around communities’ impacts on the forest, this research aimed to understand how resource extraction by two Buffer Zone villages in Nepal's Bardia National Park affects forest structure and diversity. Tree density, basal area, diameter at breast height (DBH), species richness, two diversity indices and disturbance indices were recorded in 108 plots in 12 transects, from March till May 2005, within the park along the village boundaries, where resource extraction occurs, and in the core park area which is isolated from human disturbance. Forest subject to resource extraction had a lower density of trees, smaller DBH and lower species richness and diversity. Forest disturbance declined with distance from the villages but the two villages differed widely in their impact on the forest. Resource use was more intensive in Shivapur village and percentage of trees lopped, average lopping intensity and numbers of dung piles were statistically significant. This was mainly due to the lack of access to Buffer Zone community Forest for Shivapur households. Interviews with villagers suggested that there have been changes in species availability compared to 5 years ago. Households also underestimated the impact of their resource extraction, which may prevent them from changing their behaviour to benefit conservation. It is clear that understanding rural communities’ needs, their framing of resource extraction and utilisation, and dependence on forest resources will be very helpful for long term conservation measures. 相似文献