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历史时期中国竹林分布对气候变化的响应 总被引:5,自引:2,他引:5
气温是决定植被分布的一个重要因素。通过研究我国历史上各个时期竹林分布范围的变动状况表明 ,历史上我国的气候条件经历了温暖和寒冷的几度波动 ,竹林的分布范围也相应地发生着变化。在气候较温暖的秦汉时期、隋唐时期和元朝时期 ,竹林分布到较高纬度的地方 ;在气候较寒冷的魏晋南北朝时期、南宋时期及明清时期 ,竹林的分布北界则向南移动。在温室效应引起的全球气候变暖的前景下 ,未来我国竹林的分布北界将可能会逐步北移。 相似文献
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贵州竹林的分布及类型 总被引:2,自引:0,他引:2
本文阐述了贵州竹林的水平分布和垂直分布,重点剖析楠竹林,金佛山方竹林光箨竹林、箭竹林,方竹林,毛金竹林,慈竹林,麻竹林,黔竹林。爬竹林,水竹林,斑竹林,车筒竹林,巴山木竹林,龙头竹林,箬竹林,赤竹林共17个竹林类型的分布和结构。 相似文献
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应用Weibull分布研究毛竹林分直径结构规律 总被引:6,自引:0,他引:6
本文应用 Weibull分布研究了毛竹林分直径结构规律 ,从拟合结构以及卡平方 (χ2 )检验结果得出毛竹林分直径分布密度函数曲线呈山形曲线 ,且为正偏。这对研究毛竹林分结构规律以及对毛竹林进行科学经营具有一定的理论和实际意义 相似文献
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构建了以活力、组织水平和弹性恢复力为主要指标的评价体系,建立了人工垦复——竹林生态健康关系模型:Y=0.802 064 016-0.023 261 585 034X12-0.028 516 085 034 X22,并结合湖州市的竹林特点进行分析,结果表明:随着坡度的增加,健康状况整体下降,随着竹林不科学的经营人为干扰的增加,抵抗外界干扰的能力降低;将毛竹林生态系统健康状况划分为3个类型:健康类型、健康状况一般的类型、健康状况较差的类型,人工垦复与立地坡度对森林健康有负影响;以面积比例为权重,湖州市毛竹林的管理水平指数为1.557 175,要实现湖州市毛竹林健康管理,竹林建设的坡度指数应不大于1.483 137,对应的坡度为27.415 69°,也就是说,保障湖州市竹林生态系统,发展竹林的立地坡度不适宜高于27.4°. 相似文献
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森林生态系统是人类社会赖以生存的重要生态系统类型。然而,人类活动所引起的温室效应及其造成的全球气候变化对森林生态系统的负面影响正越来越引起全世界的关注。文中系统地阐述了全球气候变化事件对森林生态系统的植被分布、迁移趋势、适应能力、火灾状况、虫害爆发、木材产量和生物多样性等诸方面所产生的重要影响。另外,森林生态系统在减缓全球气候变化的过程中发挥着极为重要的作用。文中从森林可持续发展的角度系统地分析了应对气候变化应采取的森林可持续发展的相关策略与措施,并建议通过实时监控、及时防治、科学指导、全球合作等手段进一步增强森林生态系统的适应性和减缓全球气候变化的能力。 相似文献
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Gyungsoo Cha 《Journal of Forest Research》1997,2(3):147-152
Change in potential natural vegetation (PNV) distribution associated with climate change due to the doubling atmospheric carbon
dioxide (2×CO2) was estimated with a global natural vegetation mapping system based on the modified Kira scheme to the globe and the continents.
With an input of widely-distributed global climate data, the system interpolates data onto a 1° latitude by 1° longitude grid
over the globe, generates estimates of vegetation type, and produces a composite PNV map. The input climate data corresponding
to the 1×CO2 and 2×CO2 consists of observations prior to AD 1958 at 2,001 weather stations worldwide and the 2×CO2 simulation output from the Japan Meteorological Research Institue's General Circulation Model, respectively. As a result
of the simulated global warming, the vegetation zones expanded mostly from the tropics toward the poles. PNV area changed
by 6.98 billion (G) ha of the total land area (15.04 Gha) and potential forest area corresponding to the closed forest and
open forest (woodland) reached 9.74 Gha with the increase of 1.29 Gha. The potential forest area in Europe had obvious advantages
to the climate change accompanied with the increase of actual forest area. Although the actual forest area has decreased in
North America and Asia, the potential forest area in these continents also benefitted from the climate change. In the end,
the remaining continents tended to bear the brunt of the climate change. 相似文献
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本文对国内外历史建筑再利用和功能转换的发展概况进行了分析和研究,列举了国内外历史建筑再利用的典型工程实例,指出了我国在再利用观念和方法上与西方发达国家的差距。 相似文献
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With the expected rising temperatures, outbreaks of insect pests may be more frequent, which can have large consequences on forest ecosystems and may therefore negatively affect the forestry sector. In order to be better able to predict where, but not if, outbreaks may occur in future we investigated the potential future (2070) geographical distribution of 30 prospective insect pest species (Coleoptera and Lepidoptera) by applying species distribution modelling. We also assessed the geographical extent to which the boreal forest in Sweden may be affected. We found that numerous species may experience large increases in their potential distribution in future, which may result in outbreaks in “new” areas. It is therefore likely that more trees will be infested by pests in future, which may have large implications for the Swedish forestry sector. 相似文献
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Douglas J. McRae 《林业研究》2011,22(3):437-446
Climate warming has a rapid and far-reaching impact on forest fire management in the boreal forests of China. Regional climate model outputs and the Canadian Forest Fire Weather Index (FWI) Sys- tem were used to analyze changes to fire danger and the fire season for future periods under IPCC Special Report on Emission Scenarios (SRES) A2 and B2, and the data will guide future fire management planning. We used regional climate in China (1961 1990) as our validation data, and the period (1991-2100) was modeled under SRES A2 and B2 through the weather simulated by the regional climate model system (PRECIS). Meteorological data and fire danger were interpolated to 1 km 2 by using ANUSPLIN software. The average FWI value for future spring fire sea- sons under Scenarios A2 and B2 shows an increase over most of the region. Compared with the baseline, FWI averages of spring fire season will increase by 0.40, 0.26 and 1.32 under Scenario A2, and increase by 0.60, 1.54 and 2.56 under Scenario B2 in 2020s, 2050s and 2080s, respectively. FWI averages of autumn fire season also show an increase over most of the region. FWI values increase more for Scenario B2 than for Scenario A2 in the same periods, particularly during the 2050s and 2080s. Average future FWI values will increase under both scenarios for autumn fire season. The potential burned areas are expected to increase by 10% and 18% in spring for 2080s under Scenario A2 and B2, respectively. Fire season will be prolonged by 21 and 26 days under ScenariosA2 and B2 in 2080s respectively. 相似文献
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为了衡量和反映毛竹天然混交林的生产力水平和经济效益,对不同林分组成的天然混交林的现存立竹生物量和立木蓄积量进行调查,并测算单位面积产量、产值。结果表明:不同林分组成的天然混交林经济效益均大于纯竹林,其产值比纯竹林增多18.6%~51.3%。其中,8竹1杉1阔混交林的立竹生物量最多,为99 388.4 kg/hm~2,比纯竹林增多24.1%;3竹5松2阔+杉混交林的立木蓄积量最多,达169.051 m~3/hm~2,为纯竹林的52.29倍;4竹4松1杉1阔混交林的单位面积产值最高,为39 219.2元/hm~2,比纯竹林增多51.3%。 相似文献