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1.
采用样线与样方相结合的调查方法,根据点相关系数及X^2值连续性较正公式,测定了小兴安岭凉水自然保护区具有环境梯度的7个森林类型内主要蕨类植物的种间联结。结果表明:各林型均有其适生的蕨类类群,与该类群呈正联结的蕨类种其数量分布也多,反之刚少;具有环境梯度的不同林型序列,反映出蕨类植物适生生境的不同,据此,将本区主要蕨类植物分为4种生态类型。  相似文献   
2.
地处阴山山系中段大青山脉林区的哈园,其气候区划为我国中温带亚干旱气候类型。就整体而言,四季分明,内陆气候特征强烈;但因巨大阴山山地效应,年降雨量超过450mm,植被繁茂,形成多种多样的小气候环境,以高山环境、森林环境及峡谷环境为代表,它们冷暖干湿分异形大。气候的多样性,可满足旅游者的不同要求,产生了非凡吸引力,为哈园开发建设的宝贵自然资源之一。  相似文献   
3.
2004年8月,江西省开始启动林业产权制度改革,用近一年的时间基本完成了试点工作,目前改革工作已在全省全面铺开.通过林改,明晰林业产权,减免税费,逐渐放活经营,规范流转,林业生产关系更加适应社会主义市场经济发展需要,提高了木材生产收益、群众造林护林积极性及山地租赁价格.但是,在新的林业生产关系下,许多配套管理措施还没有完善,森林保护管理工作出现一些新情况新问题不可避免.为保护好、管理好森林资源,需要对这些新变化、新情况、新问题进行研究,找出规范管理的新途径.  相似文献   
4.
We used geo-spatial statistical techniques to examine the spatial variation and relationship of soil organic carbon (SOC) and soil moisture (SM) in the Luquillo Experimental Forest (LEF), Puerto Rico, in order to test the hypothesis that mountainous terrain introduces spatial autocorrelation and crosscorrelation in ecosystem and soil properties. Soil samples (n = 100) were collected from the LEF in the summer of 1998 and analyzed for SOC, SM, and bulk density (BD). A global positioning system was used to georeference the location of each sampling site. At each site, elevation, slope and aspect were recorded. We calculated the isotropic and anisotropic semivariograms of soil and topographic properties, as well as the cross-variograms between SOC and SM, and between SOC and elevation. Then we used four models (random, linear, spherical and wave/hole) to test the semi-variances of SOC, SM, BD, elevation, slope and aspect for spatial dependence. Our results indicate that all the studied properties except slope angle exhibit spatial dependence within the scale of sampling (200 – 1000 m sampling interval). The spatially structured variance (the variance due to the location of sampling sites) accounted for a large proportion of the sample variance for elevation (99%), BD (90%), SOC (68%), aspect (56%) and SM (44%). The ranges of spatial dependence (the distances within which parameters are spatially dependent) for aspect, SOC, elevation, SM, and BD were 9810 m, 3070 m, 1120 m, 930 m and 430 m, respectively. Cross correlograms indicate that SOC varies closely with elevation and SM depending on the distances between samples. The correlation can shift from positive to negative as the separation distance increases. Larger ranges of spatial dependence of SOC, aspect and elevation indicate that the distribution of SOC in the LEF is determined by a combination of biotic (e.g., litterfall) and abiotic factors (e.g., microclimate and topographic features) related to elevation and aspect. This demonstrates the importance of both elevation and topographic gradients in controlling climate, vegetation distribution and soil properties as well as the associated biogeochemical processes in the LEF.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   
5.
The Pocono mesic till barrens (PMTB) are a unique assemblage of fire-maintained shrub communities that support numerous rare species. Historically these barrens covered a large area in the vicinity of Long Pond, Pennsylvania, USA. However, due largely to regional fire suppression instituted in the early 1960s, over 70% of the area covered by barrens succeeded to fire-intolerant forest that does not support the rare species. We investigated the influence of forest proximity on barrens succession across three geomorphic types during periods of high fire frequency and fire suppression, testing the hypothesis that forest processes such as seed rain, shading, and detrital enrichment of soils enhances barrens succession through a contagion effect. Evidence of a forest contagion effect should be shown by increased rates of barrens succession with increasing proximity to the nearest forest edge. In order to detect a forest contagion effect, barrens persistence and barrens succession were modeled in proximity zones of 0-50 m, 50-100 m, 100-200 m, and greater than 200 m from the nearest forest edge. We used existing GIS data layers for fire, geomorphology, and vegetation distribution in 1938, 1963, and 1992. The layers were modified and overlain using ArcView software to determine persistence and succession rates for each unique combination of layers in each proximity zone from 1938 to 1963 (pre-fire suppression) and 1963 to 1992 (post-fire suppression). ANCOVA results indicate that proximity to the nearest forest edge significantly affected barrens persistence rates in both time periods, but succession rates were significantly affected in 1938 to 1963 only. Twenty-eight percent of the 1938 barrens succeeded to forest by 1963; 56% of the 1963 barrens became forest by 1992. Results support previous findings that barrens persistence is enhanced by increased fire frequency, and that barrens persist longer where they overlie flat glacial till than on other geomorphology types.  相似文献   
6.
详细介绍构成龙湖省级森林公园景观资源的五大类型:生物、水域、天象、地文和人文景观资源.依据公园的性质、规划原则进行总体布局,并分别对规划的观光游览、休闲度假、激情游乐、悠游探秘四大景区的特点和园林绿化规划内容进行阐述.提出在保护自然环境的前提下,实行利用与保护兼顾,突出特色,将其规划建设成为一个兼有避暑、度假、休闲、娱乐、科普教育于一体的生态型多功能省级森林公园.  相似文献   
7.
刘洋  胡海清 《林业研究》2007,18(4):319-321
In May 2006, a high intensity wildfire occurred in Songling forest region in Daxing'an Mountains, China. The concentration changes of eight ions (K^+, Na^+, Ca^2+, Mg^2+, Cl^-, Br^-, NO3^- and SO4^2-) were measured in burned and tmbumed streams after fire from May to Oct., 2006. Results show that the most ions flux were higher in burned stream than that in unburned stream during the sampling period, and the greatest concentrations of most ions transported from burned stream occurred in July. After fire, the most amplitude chemical ion was Ca^2+, whose average concentration was 5.50 mg·L^-1 higher than that in unburned stream, and the total concentration of every chemical ion presents a trend Ca^2+〉SO4^2- 〉Na^+〉Mg^2+〉NO3^- . The average concentrations of Ca^2+, SO4^2- , Na^+'Mg^2+,NO3^- showed an increase trend, but those of K^+, Cl^- , Br had a decreased trend. SO4^2- had the largest loss among these anions, followed by NO3^-. Overall, the increase degree of cation was greater than that of anion after burning.  相似文献   
8.
在现代社会,林业的作用已不仅仅是单纯的提供绿化及木材,林业的生态效益、社会效益、经济效益可被广泛的要求所统一,从而使林业的产业化成为发展林业的一个必然趋势。林业资源发达的贵州充分利用林业资源优势大力发展林业产业化,尤其注重森林旅游的开发,成为贵州摆脱贫困的绿色经济发展路线。  相似文献   
9.
阐述了基于ArcGIS Server 9.0和J2EE技术的多层结构森林资源WebGIS的开发思想和各功能层的实现技术,在开发过程中以"瘦客户"模式作为本系统的结构模式,并采用MVC设计模式对系统功能进行分割。同时,以大兴安岭塔河林业局森林资源数据为例,介绍了森林资源空间数据的发布、森林资源WebGIS系统的组成以及其界面的定制、主要功能等。结果表明:ArcGIS Server 9.0、J2EE技术与MVC设计模式的综合使用,使整个森林资源WebGIS系统的开发效率、数据安全性、跨平台可用性、系统功能可扩充性和使用灵活性等方面较传统的双层体系结构系统得到了较大的优化和提升。  相似文献   
10.
为了将集体林生态退化区域阔叶化改造的责任主体落实到农户,解决集体林区阔叶化实施难的问题。本文针对集体林区特点,建立县、乡(镇)、村三级联动组织实施体系,并以稳定的山林经营权为依据,分别探讨了村集体统一实施、农民家庭实施、村户合作实施、招标承包实施和国有林场实施五种模式的具体做法,将农民的愿望与国家生态建设的要求统一起来,推动了集体林区阔叶化进程。  相似文献   
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