300年来中国森林的变化

Based on historical documents, modern survey and statistics, as well as the result of predecessor studies, the trend and main process of forest dynamics are recognized. The forest area and forest coverage rates for each province of China from 1700 to 1949 are estimated backward by every 50 years. Linking the result with modern National Forest Inventory data, the spatial-temporal dynamics of Chinese forest in recent 300 years （AD 1700-1998） is quantitatively analyzed. The study shows that in recent 300 years, the forest area in current territory of China has declined by 0.95×10^8 hm^2 （or 9.2% of the coverage rate） in total, with a trend of decrease and recovery. Before the 1960s, there was a trend of accelerated descending. The forest area was reduced by 1.66×10^8 hm^2 （or 17% of the coverage rate） in 260 years. While after the 1960s, there has been a rapid increase. The forest area increased by 0.7×10^8 hm^2 （or 8% of the coverage rate） in 40 years. The study also shows that there is a significant spatial difference in the dynamics of forest. The amplitudes of increasing and decreasing in western China are both smaller than the ones in eastern China. During the rapid declining period from 1700 to 1949, the most serious decrease appeared in the Northeast, the Southwest and the Southeast, where the coverage rate in most provinces dropped over 20%. In Heilongjiang Province, the coverage rate dropped by 50%. In Jilin Province, it dropped by 36%. In Sichuan Province and Chongqing Municipality, it dropped by 42%. In Yunnan Province, it dropped by 35%. During the recovery period 1949-1998, the western provinces, municipality and autonomous regions, including Ningxia, Gansu, Inner Mongolia, Sichuan-Chongqing, Yunnan, Tibet, Xinjiang and Qinghai, etc, the increase rates are all below 5%, while the eastern provinces, municipality and autonomous regions （except Heilongjiang, Hubei, Jiangsu-Shanghai） have achieved an increase over 5%, among which the Guangdong-Hainan, Guangxi, Anhui, Beijing-Tianjin-H     

东亚地区森林植被带的三维空间分布

东亚森林植被带主要由热带亚热带雨林（季雨林）、暖温带常绿阔叶林、冷温带落中阔叶林和亚寒带针叶林组成。这些植被带的垂直分布高度随纬度（温度梯度）和经度（干湿度梯度）的不同而变化，本文根据大量的地植物学资料，从生态气候学的角度研究了这种变化的规律性并给予了定理的表达。结果表明，在湿润气候区，各森林植被带的分布高度随纬度的增加而下降，下降趋势能用多级正弦函数来表达，随着经度的增加（由内陆向沿海变化），各     

基于时序遥感的庐山自然保护区植被分类及其变化分析

自然保护区是生物多样性最丰富的区域,针对近年来庐山自然保护区森林生物多样性进行调查,了解保护区内植被的分布及其变化,对于保护庐山境内的林业资源具有重要的意义.论文利用2015-2018年Proba-Ⅴ卫星100m分辨率5d植被指数产品,使用最大值合成法、Hants时间序列谐波分析方法对数据进行平滑降噪处理,并采用随机森...     

近20年来伊洛河流域典型地区森林景观格局动态

Based on the information from forest resources distribution maps of Luoning County of 1983 and 1999,six indices were used to analyze spatial patterns and dynamics of forest landscapes of the typical region in the middle of the Yihe-Luohe river basin.These indices include patch number,mean patch area,fragment index,patdch extension index,etc,The results showed that;(1) There was a rapid increase in the number of patch and total area from 1983 to 1999 in the study area,The fragment degree became very high.(2) The area of all the forest patch types had witnessed great changes,The fractal degree of each forest patch type became big from 1983 to 1999 ,The mean extension index of Robinia pseudoacacia forest ,non- forest shrub forest ,sparse forest ,and Quercus species forest in creased rapidly,but that of economic forest became zero ,The fractal dimension each showed that forest coverage has been promoted.(3)The changes of landscape patterns were different in different geomprhic regions.From 1983 to 1999 the vegetation cover area,the gross number and the density of patch,diversity and evenness of landscape were all reduced greatly in gullies and ravines,but the maximum area and the mean area of patch types were increased ,In hilly region,both the forest cover area and the number of patch increased from 1983 to 1999,but the mean area of patch was reduced greatly,In mountain region,even though the area under forest canopy reduced from 1983 to 1999 ,the patch number was increased greatly,the mean area of all patch types was reduced ,the extension index,diversity index and evenness index of landscape were all increased.Furthermore,because of different types of land use,human activtiy and terratin ,the vegetation changes on northern and southern mountain slopes were different.According to these analyses,the main driving forces,such as the policies of management,market economy,influence of human activities etc.are brought out.     

我国森林资源的地区分布

包括黑,吉、辽三省和内蒙古自治区东部的呼伦贝尔、兴安、哲里木三盟和赤峰市。     

基于GIS的石羊河流域森林生态效益估算与空间分布特征研究

利用GIS技术和数据空间化方法,通过Kriging插值获得石羊河流域平均降水量栅格图层,并以石羊河流域森林类型栅格数据为基础,结合相关统计资料,运用ArcGIS栅格计算功能及聚类方法生成石羊河流域森林涵养水源、保持水土、固碳制氧等生态效益分布图,在此基础上综合各个栅格图层,得到全流域森林生态效益量分布图,直观地反映研究...     

祁连山北坡森林资源变迁

祁连山森林是祁连山水源涵养生态系统的主体,了解祁连山森林资源变化,对于制定森林保护政策法规,有效保护和合理利用祁连山森林资源具有重要意义。2010-2013年,应用"3S"技术和搜集以往调查研究资料,对比分析了祁连山北坡森林分布范围及面积变化,结果表明:地质时期,随着祁连山快速隆升,气候变得寒冷干旱,森林分布范围逐渐缩小;早全新世以后,祁连山区森林退缩至酒泉以东山区。历史时期,祁连山北坡森林遭到4次较大规模人为破环,森林面积日渐建少。新中国建立以来至20世纪80年代末,祁连山北坡林区经过3次较大的毁林开荒行动,森林再次遭到严重破坏。改革开放以来,特别是20世纪90年代以来,国家和甘肃省加大了祁连山森林保护,祁连山北坡森林得到逐步恢复与扩展。目前,人为活动对祁连山北坡森林的干扰影响仍然严重,森林质量呈退化趋势。针对存在的问题,提出了森林保护与恢复对策。     

An approach to spatially explicit reconstruction of historical forest in Northeast China

The spatially explicit reconstruction of historical land-cover datasets plays an important role in studying the climatic and ecological effects of land-use and land-cover change（LUCC）. Using potential natural vegetation（PNV） and satellite-based land use data, we determined the possible maximum distribution extent of forest cover in the absence of human disturbance. Subsequently, topography and climate factors were selected to assess the suitability of land for cultivation. Finally, a historical forest area allocation model was devised on the basis of the suitability of land for cultivation. As a case study, we used the historical forest area allocation model to reconstruct forest cover for 1780 and 1940 in Northeast China with a 10-km resolution. To validate the model, we compared satellite-based forest cover data with our reconstruction for 2000. A one-sample t-test of absolute bias showed that the two-tailed significance was 0.12, larger than the significant level 0.05, suggesting that the model has strong ability to capture the spatial distribution of forests. In addition, we calculated the relative difference of our reconstruction at the county scale for 1780 in Northeast China. The number of counties whose relative difference ranged from-30% to 30% is 99, accounting for 74.44% of all counties. These findings demonstrated that the provincial forest area could be transformed into forest cover maps well using the model.     

小兴安岭森林生态系统中小型土壤动物生态地理分布特征

对小兴安岭森林生态系统10个生境中小型土壤动物的数量和类群组成、多样性、生态地理分布及群落排序进行研究.从水平分布看,中小型土壤动物个体数最多的是人工云冷杉林,类群数最多的是赤杨林,个体数和类群数最少的均为林间草甸.中小型土壤动物在土壤中的垂直分布具有明显的表聚性,但各生境的变化情况略有不同.10个生境多样性指数和丰富度指数在人工林和相应的天然林内的变化趋势相反.而均匀度指数和优势度指数差异不大.排序结果显示云冷杉红松林、云冷杉林、赤杨林和林间草甸与其它生境差异较大.     

气候变暖对森林生态系统的影响

近年来,全球变暖已经成为一个公认的事实。全球变暖深刻地影响着森林生态系统的各个方面,而森林生态系统的改变必然会对人类的生存和发展带来深远的影响。因此,明确森林生态系统在全球变暖背景下的变化情况,并科学合理地预测其未来的发展方向,成为研究人员与政策制定者们重点关注的问题。文章综述了国内外关于全球变暖对森林生态系统影响的研究,分别从森林土壤碳循环、植物物候、物种分布、生物多样性以及生产力5个方面进行了论述。同时,基于以上论述对未来的发展方向提出了展望。     

基于随机森林模型的西藏人口分布格局及影响因素

在乡镇尺度下厘清人口分布格局及其影响因素与区域差异,对在生态脆弱区制定可持续发展政策具有重大指导意义。基于2010年西藏自治区的乡镇尺度人口普查数据,提取人口密度和空间因子,利用空间统计方法分析了人口分布的疏密特征和集聚特征,对比运用多元线性回归方法和随机森林回归方法探索该地区人口分布的影响因素及其区域差异。结果表明：① 西藏乡镇人口密度在空间上表现出极强的非均衡性,其总体趋势是东南高西北低,高密度区与大江大河及主要交通干线具有较强的空间耦合性;② 大致以波绒乡（聂拉木县）—岗尼乡（安多县）为西藏的人口分界线,人口集聚的“核心—边缘”特征明显;③ 多元线性回归方法中,人造地表指数对人口分布的影响程度最大,随后依次为夜间灯光指数和路网密度;④ 利用随机森林方法进行的人口密度预测比多元线性回归方法精度高,可以用来对影响因子的重要性进行排序;排序在前六位的影响因子由高到低依次为夜间灯光指数、人造地表指数、路网密度、工业总产值、GDP和多年平均气温,它们与人口密度均呈正相关关系;地形地貌要素中以海拔和坡度的贡献率最大且与人口密度均呈负相关关系;⑤ 西藏人口分布格局的影响因素及其相互作用呈现出明显的区域差异特征,河谷是西藏地区人口的集聚区,主要分布在拉萨河谷、年楚河谷以及三江河谷;⑥ 通过随机森林回归分析,可以利用概念模型来表达人口分布影响因素,将主导因素概括为土地利用结构、道路通达度及城镇化水平。     

基于随机森林模型的珠江三角洲30 m格网人口空间化

人口空间化是实现人口统计数据与其他环境资源空间数据融合分析的有效途径。本文选取夜间灯光数据、道路网数据、水域分布数据、建成区数据、数字高程模型和地形坡度数据作为影响珠江三角洲人口分布的变量因子,利用随机森林模型对珠江三角洲2010年人口数据进行了30 m格网空间化,并将模拟结果与三个公开数据集作精度对比,最后基于随机森林模型的变量因子重要性分析珠江三角洲人口空间分布的影响因素。结果表明：本文模拟整体精度达到82.32%,均优于WorldPop数据集以及中国公里网格人口数据集,接近GPW数据集,而且在人口密度中等区域模拟精度最高;通过对变量因子重要性进行度量,发现夜间灯光强度是珠江三角洲人口分布的最重要指示性指标,到水域的距离、到建成区的距离和路网密度对珠江三角洲人口分布均具有重要作用。利用随机森林模型结合多源信息能够实现高空间分辨率的人口空间化,可为精细化城市管理提供重要数据源,也可为相关政策决策制定提供支持。     

半干旱区植被恢复与岩土性质

文章分析了半干旱区不同岩土组成的坡地的土壤水份特征及对植被类型的影响,阐述了黄土高原地区森林分布与黄土厚度的关系,给出了云南元谋干热河答阶地砾石层、泥岩、片岩组成的荒山的植被恢复实例。     

我国落叶松林生产力的空间变化特征

落叶松林在我国有着广泛的分布。其空间差异也比较大。采用地统计学方法对我国落叶松林生产力的空间特征进行了分析。结果表明。落叶松种群和群落地理替代作用明显；落叶松林生产力空间异质性较大。其变化与空间尺度密切相关；地理位置、海拔高度等是影响落叶松林生产力的重要因素；在天然落叶松林的管理和保护以及人工落叶松林的发展上应考虑其空间特征。     

试论建历史上若干洪灾与森林过伐的关系

本文通过对建瓯只籍上有关洪灾记载与城市建设、林木销售等情况的统计分析,揭示了建瓯历史上的若干洪灾与森林过伐之间存在着一定的相关性,进而强调提出,建瓯作为一个森林大县（市）,同样不能忽视对“森林保护神”的保护,合理地保护和开发利用森林资源,是人类永恒不变的主题。     

试论具有岭南文化特色的广州城市森林的建设

岭南文化作为一种地域文化,其标志和典范是广东文化,广州是岭南文化的中心,其特色须由岭南文化铸就,广州城市森林如何渗透岭南文化,具有独特的岭南风格,对于振兴岭南文化,塑造广州新的形象和风格,形成广州城市特色,具有重要意义,文中分析了广州城市森林实现具有备岭南文化特征的途径,认为根据文化内涵,表现形式和手法,具体体现为五个方面：（１）以营建岭南乡土树种片林为主体;（２）发展岭南园林;（３）引进抽象式园