中国东部森林样带典型森林水源涵养功能

通过对我国东部森林样带四个森林生态系统定位研究站（长白山站、北京站、会同站和鼎湖山站）的九种森林类型水源涵养监测数据的分析,研究了水热梯度下不同森林生态系统水源涵养功能。结果表明：在生长季的5-10月份,各森林类型的水源涵养特性表现出较大差异。林冠截留率的大小依次为：阔叶红松林＞杉木林＞常绿阔叶林＞针阔混交林＞季风常绿阔叶林＞落叶阔叶混交林＞马尾松林＞落叶松林＞油松林,最高的长白山站阔叶红松林的截留率是最低的北京站油松林的2.2倍。森林降雨截留量与林外降雨量呈显著的正相关,林冠截留率与降雨量呈显著负相关。枯落物最大持水深（5-10月份）以北京站落叶阔叶林最大,为6.0mm;鼎湖山站的季风常绿阔叶林最小,为1.0mm。0-60cm土层蓄水量最大的是会同站的人工杉木林,为247mm;最小的是北京站的落叶松林,仅为45.5mm;林分总持水量依次为：杉木林＞阔叶红松林＞常绿阔叶林＞针阔混交林＞季风常绿阔叶林＞落叶阔叶混交林＞马尾松林＞落叶松林＞油松林。各林分总持水量主要集中在土壤层,占总比例的90%以上。     

云贵高原抚仙湖近13300年的花粉/炭屑记录*

抚仙湖是云贵高原著名的断陷深水湖,其沉积物蕴藏着流域地质历史时期丰富的环境信息。对钻取自该湖的900cm 湖泊沉积物岩芯进行花粉/炭屑分析及花粉数据的主成分分析表明,抚仙湖流域的植被、气候与火灾在过去的13 300年经历了5个阶段的变化：(1)13 300—10 400cal．a BP,植被以松林为主,伴有山地暗针叶林和常绿阔叶林,表明该时期气候较为冷湿,森林火灾多发,在后期随着温度和湿度的降低,森林火灾愈加频繁。(2)10 400—5 700cal．a BP,松林收缩,常绿阔叶林扩张,出现一定数量的落叶阔叶林,显示该时期气候偏暖偏干;此阶段早期随着气候变暖变干森林火灾的发生延续上阶段高发的状态,直到9 500cal．a BP后随着湿度的增加森林火灾明显减少。(3)5 700—1 800cal．a BP,松林变化较小,常绿/落叶阔叶林比重增大,首次出现了暖热性的枫香林,显示该时期暖湿的气候特征,火灾发生频率低。(4)1 800—500cal．a BP,松林扩张,阔叶林收缩,本阶段后期草本植被比重开始增加,显示该时期气候相对冷干,森林火灾发生频率较高。(5)500cal．a BP至今,松林收缩,落叶阔叶树种增多,草本植物花粉明显增多,显示该时期气候温凉偏干,森林火灾发生频率降低。     

东喜马拉雅南翼山地的半常绿阔叶林

在世界具有湿润和半湿润气候的地区,广泛生长着由各类阔叶乔木组成的森林。在植被分类系统中,学者们根据其群落的生态外貌、区系组成等特点,将它们划分为常绿阔叶林,硬叶常绿阔叶林,落叶阔叶林和常绿、落叶阔叶混交林,雨林,季风雨林,红树林等几种不同的植被类型。1982年8月—1983年9月,我参加中国科学院南迦巴瓦峰登山科学考察队,在东喜马拉雅南坡的墨脱县进行越冬考察时,发现了一种与上述各类型都不     

河南植被水平地带性的分布规律

河南植被纬向性分布与气温有关。北部属温带落叶林区域,典型植被,山地为落叶阔叶林和常绿针叶林,东部平原的农作物为一年两作或两年三作。南部为亚热带常绿阔叶林区域的常绿、落叶阔叶混交林地带,典型植被为含有常绿成分的落叶阔叶林,针叶林由马尾松、黄山松和杉木林组成。河南植被的经向性分布职决于干燥度引起的地带性变化,东部大别山的植被由黄山松林和茶园来表征,南部的桐柏山地带则没有黄山松林和茶园。     

常绿阔叶林植被动态研究进展

常绿阔叶林是亚热带地区的地带性植被,是亚热带陆地生态系统的重要组成部分,几十年来,中国的植物学家、生态学家对常绿阔叶林的区系成分、物种组成、外貌和结构、动态以及作为生态系统成员的功能等方面进行了大量的研究,积累了丰富的资料,取得了大量的研究成果,同时也在四川缙云山、浙江天童山、广东省鼎湖山和黑石顶、云南哀牢山、福建武夷山逐步形成了中国各具区域特色的常绿阔叶林研究基地,为常绿阔叶林的研究作出了突出的贡献。在常绿阔叶林的演替方面,研究内容从研究常绿阔叶林群落演替的过程、群落组成变化、结构动态及模型逐步向生态系统物质循环和能量流动发展,但对常绿阔叶林主要优势种动态、生理生态和群落演替机理等方面深入不够。在常绿阔叶林的更新动态研究方面,不但进行了通过研究种子雨和种子库的动态、种子的萌发、幼树生长的时空动态研究群落的更新,而且还通过研究林窗的形成、特征及其在森林动态中的作用来研究群落的更新,还进一步通过对常绿阔叶林主要树种更新植株的生理生态特性的研究来解释群落更新的原因。在常绿阔叶林退化和恢复重建研究方面,研究了常绿阔叶林各种退化生态系统的特征和恢复过程等,并将已有的理论和技术应用于退化生态系统的恢复和重建。即是以前人研究的成果为基础,从群落的演替、更新、退化和恢复等方面对我国多年来常绿阔叶林植被动态的研究作一总结。根据国内外的研究趋势提出了常绿阔叶林的动态方面急需开展3s技术在常绿阔叶林上的应用研究、常绿阔叶林的退化的生理生态机制、常绿阔叶林起源与系统发育、常绿阔叶的林保护与恢复生态学、常绿阔叶林重要物种的生理生态学和种群生物学、常绿阔叶林生态服务功能与区域可持续发展模式以及常绿阔叶林生态系统对全球变化的作用与响应机制等方面的研究。     

中国东部森林植被带划分之我见

简要回顾了中国东部森林植被带划分研究的历史及当前存在的争论。提出了中国东部植被带划分应以植被本身的特征,特别是地带性的生物群落集为主要依据,同时参照它们的区系组成和气候指标。根据上述原则将中国东部划分为6个植被带∶北方针叶林带、凉温带针阔混交林带、温带落叶阔叶林带、暖温带常绿落叶阔叶混交林带、亚热带常绿阔叶林带和热带雨林、季雨林带,并对各植被带的特征作了简要的描述。阐述了对一些植被带名称、界线改动的原因,特别讨论了我国常绿落叶阔叶混交林以及常绿阔叶林生物气候带的归属问题,认为前者归属于暖温带植被,后者归属于亚热带植被为宜。     

中国东部森林植被带划分之我见

简要回顾了中国东部森林植被带划分研究的历史及当前存在的争论。提出了中国东部植被带划分应以植被本身的特征，特别是地带性的生物群落集为主要依据，同时参照它们的区系组成和气候指标。根据上述原则将中国东部划分为６个植被带∶北方针叶林带、凉温带针阔混交林带、温带落叶阔叶林带、暖温带常绿落叶阔叶混交林带、亚热带常绿阔叶林带和热带雨林、季雨林带，并对各植被带的特征作了简要的描述。阐述了对一些植被带名称、界线改动的原因，特别讨论了我国常绿落叶阔叶混交林以及常绿阔叶林生物气候带的归属问题，认为前者归属于暖温带植被，后者归属于亚热带植被为宜。     

西双版纳热带雨林和哀牢山亚热带常绿阔叶林雾特征研究

以西双版纳热带雨林和哀牢山亚热带常绿阔叶林为研究对象,利用PWS100天气现象仪获取两种森林类型的能见度数据。基于2014年西双版纳热带雨林和哀牢山亚热带常绿阔叶林的能见度数据,对两种森林类型雾的特征进行定量研究。研究结果表明:(1)西双版纳热带雨林全年雾日数为196 d,占全年的53.7%,哀牢山亚热带常绿阔叶林全年雾日数为100 d,占全年的27.4%,热带雨林全年雾日数几乎为亚热带常绿阔叶林雾日数的两倍;(2)热带雨林雨季和干季各占28.06%和71.94%,而亚热带常绿阔叶林雨季和干季各占72%和28%;(3)热带雨林一日内雾持续的最长时间为10.5 h,而亚热带常绿阔叶林雾生成和消散时间不定,一日内雾最长持续时间可达24 h,但雾发生的频率低于西双版纳热带雨林。两种森林类型全年雾日特征有明显的差异性,通过定量评价地处过渡带上的两种多雾森林生态系统雾特征,可为未来气候变化对不同森林生态系统碳水交换影响提供数据支撑。     

云南常绿阔叶林的类型和特点

常绿阔叶林是指由壳斗科、茶科、樟科、木兰科的常绿阔叶树种为主组成的森林,但不包括常绿阔叶的热带雨林和常绿阔叶的山地硬叶林。常绿阔叶林主要分布在亚热带较湿润的气候条件下,所以也称之为“亚热带常绿阔叶林”。我们在植被文献中所见到的“照叶林”、“樟栲林”、“常绿栎类林”、“亚热带山地雨林”、“亚热带常绿季雨林”等等,都属于这一类森林范围。当然,它也应包括含有温带落叶成分的常绿阔叶林。     

渝东山地黄壤肥力变化与植物群落演替的关系

从土壤的理化因子出发,利用综合评价的方法,对渝东地区城口县坪坝区大巴山南坡山地黄壤的土壤肥力变化特征与地上植被类型之间的关系进行了研究.结果表明,马尾松林、杉木林、落叶栎类林、茶树林和常绿阔叶林下土壤肥力的综合指标值分别为0.1256、0.2085、0.351、0.2479、0.9329.阔叶林(落叶栎类林、茶树林和常绿阔叶林)下山地黄壤的土壤肥力综合指标值均大于针叶林(马尾松林、杉木林)下山地黄壤的土壤肥力综合指标值.即使在同一植被类型下,由于建群种的不同,其土壤肥力综合指标值也不相同.根据植物群落演替的过程可以断定土壤的发育与植物群落演替是两个密不可分、相辅相成的过程.     

我国北方针叶林人为火发生的预测模型

我国北方针叶林带是重要的森林资源储藏地,也是林火发生的重灾区,其自然火和人为火所占比例相当. 气象因子、地形特征、植被条件、人为基础设施等因素对人为火发生具有显著影响,国内目前应用空间分析技术对北方针叶林带人为火影响因子的研究还存在一定不确定性. 本文基于1974—2009年间人为火的空间地理坐标,结合研究地的气象因子、基础地理信息及矢量化林相图,应用ArcGIS 10.0中的空间分析工具和SPSS 19.0的逻辑斯蒂回归模型对影响人为火发生的主要驱动因子进行分析,并建立人为火发生的概率模型. 利用HADCM2模式下研究区域未来气象数据对塔河地区2015年人为火发生情况进行计算.结果表明： 距离铁路距离（x₁）和平均相对湿度（x₂）对研究区域人为火发生具有显著影响,并得到火险概率模型P=1/［1+e^{-(3.026-0.00011x1-0.047x₂)}］. 模型校验结果显示,模型的准确度可达到80%.林火发生预测结果表明,塔河地区2015年 4—6月、8月为人为火高发期,其中,4—5月的林火发生概率最高.从火险空间分布来看,高火险主要集中在塔河西部和西南部,铁路线路主要包含在此区域.     

Recent fire regime characteristics and potential natural vegetation relationships in Spain

Abstract. In heavily altered landscapes, where vegetation is not natural and where people are the main source of ignitions, relationships between fire occurrence and climate conditions may be unclear. The objective of this study was to evaluate to what extent territories with similar Potential Natural Vegetation (PNV) in peninsular Spain differ in their forest fire characteristics. From 1974 to 1994, more than 174 000 fires occurred. We used (1) the Spanish data base of forest fires, (2) a PNV map and (3) a land use map. Separate fire characteristics, based either on the number of fires occurred or the area burned, were obtained for each of the ca. 5000 grid‐cells (10 km × 10 km) into which peninsular Spain is divided in the UTM projection. Also, meteorological conditions at the time of fire ignition, cause of ignition and present forest cover were referred to the same grid‐cells as external factors potentially determinant of fire occurrence. The relationships between fire regime characteristics and PNV units were explored with Principal Components Analysis (PCA). The role of the three sets of external factors in the fire characteristics was evaluated with Redundancy Analysis (RDA). Groups of similar PNV types were clearly segregated, suggesting a gradient of fire characteristics. Higher fire incidence (higher frequencies and spatial incidence of fires, but lower proportions of grid‐cells affected by large fires) was associated with Atlantic, warm territories with deciduous forests as PNV. Intermediate fire frequency and rotation period, but with a higher relative incidence of medium and large fires occurred in Mediterranean PNV units, dominated by sclerophyllous oak forests. Low fire frequency and long rotation periods, with strong seasonal and yearly variability occurred for PNV units in the cold uplands (Fagus, Pinus, Abies, Juniperus) or in the semi‐arid, shrubby PNV units. The cause of ignition best explained the patterns of forest fire characteristics, followed by weather conditions. Our results indicate that, even in human influenced regions, climate and soil conditions exert control on the resulting forest fire characteristics, as indicated by the high segregation of the PNV types. However, the role of man was crucial in shifting the patterns of fire incidence. This was so that highest fire incidence occurred in regions that, otherwise, would be expected to have a much lower one, thus posing a serious threat for such areas. PNV maps, by providing a phytogeographical framework for characterizing forest fires, could be valuable tools for applying research results to forest fire management policies, taking properly into account the underlying determinant factors.     

Integration of Lightning- and Human-Caused Wildfire Occurrence Models

Fire risk indices are useful tools for fire prevention actions by fire managers. A fire ignition is either the result of lightning or human activities. In European Mediterranean countries most forest fires are due to human activities. However, lightning is still an important fire ignition source in some regions. Integration of lightning and human fire occurrence probability into fire risk indices would be necessary to have a complete picture of the causal agents and their relative importance in fire occurrence. We present two methods for the integration of lightning and human fire occurrence probability models at 1 × 1 km grid cell resolution in two regions of Spain: Madrid, which presents a high fire incidence due to human activities; and Aragón, one of the most affected regions in Spain by lightning-fires. For validation, independent fire ignition points were used to compute the Receiver Operating Characteristic (ROC)-Area Under de Curve (AUC) and the Mahalanobis Distance. Results in Madrid are satisfactory for the human fire occurrence probability model (AUC～0.7) but less suitable for the lightning and the integrated models. In Aragón the fit for the human model is reasonable (AUC～0.7) whereas for the integration methods is practically useless (AUC～0.58).     

不同植被类型森林火灾及雷击火自组织临界性

利用黑龙江省大兴安岭林区呼中区 196 5～ 2 0 0 2年的雷击火数据、黑龙江省 1981～ 2 0 0 0年森林火灾数据及森林资源数据 ,对雷击造成的森林火灾的自组织临界性及不同植被类型条件下的自组织临界性作了研究 ,比较了在不同尺度和植被类型条件下火干扰的自组织临界性、自相似性 ,并与传统的森林火灾元胞自动机模型模拟的结果进行比较。结果表明 :中国黑龙江省不同森林类型的火干扰具有自组织临界行为 ,森林可燃物已经达到临界状态 ,其临界值在 1.8～ 2 .86之间 ,具有自相似性 ;当森林的面积过小时 ,森林火灾的“面积 -频率”分布曲线上会出现频率峰 ,表现出“有限面积效应”现象。     

我国林火发生预测模型研究进展

通过文献回顾,总结了国内林火发生预测模型的研究现状,并从林火发生驱动因子、林火发生概率预测模型、林火发生频次预测模型和模型检验方法等方面进行归纳分析。得出以下结论: 1)气象、地形、植被、可燃物、人类活动等因素是影响林火发生及模型预测精度的主要驱动因子;2)林火发生概率模型中,地理加权逻辑斯蒂回归模型考虑了变量之间的空间相关性,Gompit回归模型适宜非对称结构的林火数据,随机森林模型不需要多重共线性检验,在避免过度拟合的同时提高了预测精度,是林火发生概率预测模型的优选方法之一;3)林火发生频次模型中,负二项回归模型更适合对过度离散数据进行模拟,零膨胀模型和栅栏模型可以处理林火数据中包含大量零值的问题;4)ROC检验、AIC检验、似然比检验和Wald检验方法是林火概率和频次模型的常用检验方法。林火发生预测模型研究仍是我国当前林火管理工作的重点,预测模型的选择需要依据不同地区林火数据特点。此外,构建林火预测模型时需要考虑更多的影响因素,以提高模型预测精度;未来,需要进一步探索其他数学模型在林火发生预测中的应用,不断提高林火发生预测模型的准确度。     

呼中林区火烧点格局分析及影响因素

林火是森林生态系统景观格局、动态和生态过程的重要自然驱动力,理解林火发生空间格局与影响因素对于林火安全管理具有重要的作用。采用点格局分析方法,以黑龙江大兴安岭呼中林区1990-2005年火烧数据为研究案例,分析了火烧点空间格局及其影响因素。结果表明,火烧点在空间上的分布是不均匀的,呈现聚集分布,存在一些火烧高发区和低发区。呼中林区火烧概率是0.004-0.012次/(km² · a),平均火烧概率为0.0077次/(km² · a)。人类活动因子、地形因子和植被因子对林火的发生均具有重要作用。应用空间点格局分析方法表明,距离居民点和道路的距离、高程、坡度和林型是影响林火发生的显著因子。因此在进行森林防火管理时,仅仅通过控制人类活动对于降低林火火险的效果是有限的,地形和林型也是林火防控时重点要考虑的因素。     

基于MODIS卫星火点的浙江省林火季节变化及驱动因子

研究林火变化趋势和驱动因子,可为林火预防和管理提供科学依据。本研究基于MODIS卫星火点数据,结合气象(日平均风速、日平均温度、日相对湿度、气温日较差、日累计降水)、人为(到公路距离、到铁路距离、到居民点距离、人口密度、人均GDP)、地形和植被因素(高程、坡度、植被覆盖度),运用趋势分析法、Logistic回归模型,对浙江省2001—2016年林火变化趋势和驱动因子进行研究。结果表明: 浙江省春、夏季林火呈显著上升趋势,秋、冬季林火呈先上升后下降趋势,秋季下降趋势显著。浙江省各季节林火预测模型拟合度均较高,模型预测准确率分别为75.8%(春季)、79.1%(夏季)、74.7%(秋季)和79.6%(冬季)。浙江省春、夏季林火发生与变化受气象、人为、地形和植被因素的显著影响;秋、冬季林火发生与变化主要受气象因素影响。在影响因素复杂、高火险区域分散的春、夏季,林火管理应重点加强人为活动管理和防火宣传教育;在秋、冬季,可通过在高火险区集中分布的西南地区增设瞭望塔和监控设备进行监测和管理。     

Firescape ecology: how topography determines the contrasting distribution of fire and rain forest in the south‐west of the Tasmanian Wilderness World Heritage Area

Aim To test the hypothesis that ‘islands’ of fire‐sensitive rain forest are restricted to topographic fire refugia and investigate the role of topography–fire interactions in fire‐mediated alternative stable state models. Location A vegetation mosaic of moorland, sclerophyll scrub, wet sclerophyll eucalypt forest and rain forest in the rugged, fire‐prone landscapes of south‐west Tasmania, Australia. Methods We used geospatial statistics to: (1) identify the topographic determinants of rain forest distribution on nutrient‐poor substrates, and (2) identify the vegetation and topographic variables that are important in controlling the spatial pattern of a series of very large fires (> 40,000 ha) that were mapped using Landsat Thematic Mapper (TM) satellite imagery. Results Rain forest was more likely to be found in valleys and on steep south‐facing slopes. Fires typically burned within highly flammable treeless moorland and stopped on boundaries with less flammable surrounding vegetation types such as wet sclerophyll forest and rain forest. Controlling for the effect of vegetation, fires were most likely to burn on flats, ridges and steep north‐facing slopes and least likely to burn in valleys and on steep south‐facing slopes. These results suggest an antagonism between fire and rain forest, in which rain forest preferentially occupies parts of the landscape where fire is least likely to burn. Main conclusions The distribution of rain forest on nutrient‐poor substrates was clearly related to parts of the landscape that are protected from fire (i.e. topographic fire refugia). The relative flammability of vegetation types at the landscape scale offers support to the proposed hierarchy of fire frequencies (moorland > scrub > wet sclerophyll > rain forest) that underpins the ecological models proposed for the region. The interaction between fire occurrence and a range of topographic variables suggests that topography plays an important role in mediating the fire–vegetation feedbacks thought to maintain vegetation mosaics in south‐west Tasmania. We suggest that these fire–topography interactions should be included in models of fire‐mediated alternative stable vegetation states in other fire‐prone landscapes.     

Effects of climate on occurrence and size of large fires in a northern hardwood landscape: historical trends,forecasts, and implications for climate change in Témiscamingue,Québec

Questions: What climate variables best explain fire occurrence and area burned in the Great Lakes‐St Lawrence forest of Canada? How will climate change influence these climate variables and thereby affect the occurrence of fire and area burned in a deciduous forest landscape in Témiscamingue, Québec, Canada? Location: West central Québec and the Great Lakes‐St Lawrence forest of Canada. Methods: We first used an information‐theoretic framework to evaluate the relative role of different weather variables in explaining occurrence and area burned of large fires (>200 ha, 1959‐1999) across the Great Lakes‐St Lawrence forest region. Second, we examined how these weather variables varied historically in Témiscamingue and, third, how they may change between the present and 2100 according to different scenarios of climate change based on two Global Circulation Models. Results: Mean monthly temperature maxima during the fire season (Apr‐Oct) and weighted sequences of dry spells best explained fire occurrence and area burned. Between 1910 and 2004, mean monthly temperature maxima in Témiscamingue showed no apparent temporal trend, while dry spell sequences decreased in frequency and length. All future scenarios show an increase in mean monthly temperature maxima, and one model scenario forecasts an increase in dry spell sequences, resulting in a slight increase in forecasted annual area burned. Conclusion: Despite the forecasted increase in fire activity, effects of climate change on fire will not likely affect forest structure and composition as much as natural succession or harvesting and other disturbances, principally because of the large relative difference in area affected by these processes.     

Wildfire refugia in forests: Severe fire weather and drought mute the influence of topography and fuel age

Wildfire refugia (unburnt patches within large wildfires) are important for the persistence of fire‐sensitive species across forested landscapes globally. A key challenge is to identify the factors that determine the distribution of fire refugia across space and time. In particular, determining the relative influence of climatic and landscape factors is important in order to understand likely changes in the distribution of wildfire refugia under future climates. Here, we examine the relative effect of weather (i.e. fire weather, drought severity) and landscape features (i.e. topography, fuel age, vegetation type) on the occurrence of fire refugia across 26 large wildfires in south‐eastern Australia. Fire weather and drought severity were the primary drivers of the occurrence of fire refugia, moderating the effect of landscape attributes. Unburnt patches rarely occurred under ‘severe’ fire weather, irrespective of drought severity, topography, fuels or vegetation community. The influence of drought severity and landscape factors played out most strongly under ‘moderate’ fire weather. In mesic forests, fire refugia were linked to variables that affect fuel moisture, whereby the occurrence of unburnt patches decreased with increasing drought conditions and were associated with more mesic topographic locations (i.e. gullies, pole‐facing aspects) and vegetation communities (i.e. closed‐forest). In dry forest, the occurrence of refugia was responsive to fuel age, being associated with recently burnt areas (<5 years since fire). Overall, these results show that increased severity of fire weather and increased drought conditions, both predicted under future climate scenarios, are likely to lead to a reduction of wildfire refugia across forests of southern Australia. Protection of topographic areas able to provide long‐term fire refugia will be an important step towards maintaining the ecological integrity of forests under future climate change.