森林对河川径流影响关系的研究进展

国外森林和水分的关系的科学研究始于20世纪初,森林与径流关系的研究方法大致有大范围的计量分析研究、一个林区或林场的计量调查、小范围的定位观测试验3大类。森林对径流影响的研究主要有森林对年径流的影响、森林对洪水径流的影响、森林对枯水径流影响等几个方面。今后应加强合作研究,特别是利用网络研究对比不同集水区之间的结果来探讨森林对径流的影响,同时重视新技术和新方法的应用。     

国内外森林对河川径流影响关系的研究进展

国外森林和水分的关系的科学研究始于20世纪初，我国起步于1949年；森林与径流关系的研究方法大致有大范围的计量分析研究、一个林区或林场的计量调查、小范围的定位观测试验3大类。森林对径流的研究主要有森林对年径流的影响、森林对洪水径流的影响、森林对枯水径流影响等几个方面。今后应加强合作研究，特别是利用网络研究对比不同集水区之间的结果来探讨森林对径流的影响，同时重视新技术和新方法的应用。     

鸡公山5种森林水样的水质分析

在森林区域内,大气降水、穿透雨、树干径流、地表径流和集水区径流5种类型水样的表现性状可以大致模拟大气降水对森林垂直层面的作用与影响.本文通过对2020年3月-10月期间鸡公山森林区域内的上述5种类型水样的pH值等水质指标进行定位观测和对比,得到了该区域内穿透雨、树干径流和地表径流的大部分指标浓度值高于大气降水从而呈现正向效应,集水区径流的大部分指标浓度低于大气降水则呈反向效应的结论.并通过对实验结果的分析,阐释了大气降水透过森林林冠层、林下枯落物层的元素变化规律,为深入研究森林水文的内在运行机制提供依据.     

松华坝水源区森林微集水区降雨与径流过程分析

微集水区是山区最基本的水文单元,其降雨产流特征研究可以为流域水文的规律研究提供重要的数据支持。针对迤者小流域的森林微集水区进行不间断观测,得出结论:降雨量直接影响微集水区的径流产生量,7月19日24h内降雨量为36.6mm,降雨性产流105.57m3;径流洪峰一般滞后于降雨量峰值,7月19日降雨—径流监测中,最大产流值滞后最大降雨量值2h50min。     

采伐方式与水土保持

苏联科学院通讯院士A·A·莫尔恰诺夫指出,由于采伐木材,森林覆盖率下降,径流层和径流系数便增加,而在皆伐迹地上则几乎增长9倍。伐区的分布位置甚为重要,集水区下部的伐区对径流影响最大。上部和中部的皆伐迹地上形成的地表径流被集水区下部未经采伐的森林所吸收。在头5—6年内采伐对径流和径流系数变化的影响最大。美国在科罗拉多州选了两个毗邻的、完全绿化的集水区,面积各约90公顷。经8年观测     

西双版纳橡胶-咖啡人工群落降雨径流初步研究

由降雨造成的径流(地表径流和地下径流)是水分循环和水量平衡的基本要素,是气候、植被、地理因素相互作用的结果。因地表径流的快速流失,缓慢有序的地下径流成了控制土壤水分变化的主导因子。区分地表径流和地下径流的关键是确定下渗率Fc,进而研究土壤水的补给及流出规律。现利用自然流域集水区连续4年的观测资料,研究分析土壤的降雨径流及下渗率的变化规律。1　自然概况和观测方法实验集水区位于云南省勐腊县勐仑镇热带生态站(101°15′E,21°56′N,海拔560m)橡胶-咖啡人工群落区,其内选一地形完整的小流域(面积为10hm2),平均坡度15°。…     

大岗山人工针阔混交林与常绿阔叶林水文动态变化研究

采用定位观测方法与水集水区试验技术方法，利用1-6月份艰测数据，从土壤水分、坡面径流、集水区径流量等方面对大岗山地区人工针阔混交林、天然常绿阔叶林典型森林集水区的森林水文动态变化规律进行了研究。结果表明：⑴人工针阔混交林森林土壤水分量大值（51.8mm）出现在5月份，最小值（33.2mm）出现在3月份，且垂直变化幅度不大。⑵坡面径流量月变化较大，与一次性降水有密切关系，可用指数式y=0.1266e^0.0502x表示。⑶与人工针阔混交林相比，天然常绿阔叶林具有较强水土保持能力和显著水源涵养作用。     

从森林集水区增加径流的潜力

森林实际上仅仅作为景观要素而已,至今仍未深刻地受到技术发展的影响。森林集水区里不断形成相当数量的水资源,同时森林集水区的水质优良,可溶性化学物质的含量比田间集水区低几倍。目前,人们日益重视寻找从森林集水区获得更多径流量的方法。众所周知,人们感兴趣的试验是砍伐或更新与其它植物群落混生的森林对径流的数量及质量的影响,但是对     

森林生态系统物质循环研究中的生物地球化学方法和实验技术

本文论述了中南林学院近五年来建立森林生态系统观测站,开展杉木人工林生态系统研究的方法——小集水区径流场综合实验法。从方法论上探讨了把森林生态系统定义在小集水区可辨和可控边界条件下,辅以径流场封闭技术和实验设施,从而准确测定系统内各种营养物质的输入、再分配和输出,以及森林水文学过程中的物理和化学等方面的问题。并用部分实验数据作了对比分析和验证。为南方山区建立森林定位观测站提供了借鉴。     

美国森林集水区研究进展

森林集水区研究,主要是探讨森林与水的关系。既是森林生态系统研究的主要环节,也是水土保持的一项基础研究。美国在这方面起步较早,已有七十余年的研究历史。随着人口增加和现代科学技术的发展,人类经济活动对环境污染程度和范围,也日益扩大.森林集水区试验,已由水量研究转向水质研究。还包括了林地放牧、农业集水区、山地农业所引起水土流失的变化研究,如渗透速度、迳流量、土壤物理性状、水质分析等。近些年来,随着新     

生态环境需水的研究进展

文章针对生态环境需水的内涵、国内外研究现状、目前主要采用的研究方法及理论基础作了综述,并指出了在生态环境需水研究中存在的诸多问题,如生态环境需水的合理性界定问题、系统整合性问题、重复性问题、时空尺度问题。在此基础上提出了未来生态环境需水研究的几点建议:完善生态环境需水的理论体系;研究森林蒸散耗水的生态机理与不同类型林木的耗水规律,结合遥感和GIS在测量与计算植被生态需水量的应用,提高区域林木需水量的计算精度;生态环境需水研究时间尺度应与水资源的合理配置与生态环境建设一致等。     

Long-term changes in forest cover 1780–2007 in central Bohemia, Czech Republic

Many studies have recently been devoted to the study of landscape change, and some have even focused on an analysis of the dynamics of forest cover change. However, few of the studies have worked on a methodology for making a detailed investigation of long-term forest change dynamics based on historic cartographic sources. The goal of this study is to further develop a method for analyzing long-term changes in forest cover on the basis of old maps and orthophoto maps in the GIS environment. The study area is located in Central Bohemia, to the east of Kutná Hora, a UNESCO World Heritage Site. The area consists of 21 cadastral units with a total area of 113 km². The maps of the First (1780), Second (1851) and Third Military Surveys (1877) and the present-day orthophotomap (2007) of the Czech Republic were used as data resources. Source data have been processed in GIS. Forest cover is the subject of our study. However, the term is perceived from a broader perspective. What we call forest cover in our study refers to forest wood elements and other wood species in the landscape. In this study, forest cover has been structurally considered as a whole, without dividing it into the two categories mentioned. We counted the extent of the forest cover in each particular time horizon in hectares and as a percentage of the area under study, also the absolute changes in forest cover between the individual time horizons in hectares as well as the intensity of the changes in forest cover in hectares per year. The spatial changes in forest cover were evaluated in a GIS environment using specialized features to analyze spatial variation. The forest cover occupied 16.60% (1,880 ha) of the total area in the First Military Survey (1780). In 2007, the proportion was slightly higher at 16.64% (1,884 ha). More than half of all forest land (53%) from the time of the Second Military Survey (1851) survived until 2007. Not only the information on absolute changes but also the information on the rate of change is of great importance. The old Military Survey maps and the orthophotomap enable us to carry out studies of long-term changes in forest cover. However, the geodetic inaccuracy of the First Military Survey maps precludes reliable and exact quantification of the landscape changes between the First Military Survey and the Second Military Survey, and also between the First Military Survey and present-day (orthophoto map). These maps cannot be used for evaluating forest cover changes on the level of individual plots. The method presented in our paper may contribute to a better understanding of the long-term dynamics of forest land, covering a period of more than 250 years. This knowledge can be applied in forest management planning procedures. Apart from their application in forestry, the methods presented in this study may be of interest for historians and biologists.     

Direct measurements of carbon exchange at forest disturbance sites: a review of results with the eddy covariance method

ABSTRACT

Boreal and temperate forests cover a large part of the Earth. Forest ecosystems are a key focus for research because of their role in the carbon (C) balance and cycle. Increasing atmospheric temperatures, different disturbances (fire, storm and insects) and forest management (clear-cutting) will change considerably the C status of forest ecosystems. Using the eddy covariance (EC) method, we can define interactions among environmental factors that influence the C-balance and whether a forest ecosystem is functioning as a C-sink or C-source or possibly is C-neutral. In our review of published studies of different disturbances, we found that most of the post-disturbance studies based on EC method focused on the effects of forest fire and clear-cutting, only a few studies studies focused on the effects of storms and insects. Generally a forest is a C-source until several years after disturbance and then a forest is able to absorb C and become a C-sink. Recovery to C-sink status required up to 20 years in clear-cut areas. Recovery following wildfire disturbance was much longer, possibly more than 50 years. Recovery to C-sink status required approximately 5 years after storm and insect outbreak, however we can not predict overall recovery period because of the missing data.     

Inclusion of forest harvest legacies, forest type, and regeneration spatial patterns in updated forest maps: A comparison of mapping results

In Maine and other heavily forested states, existing land cover maps quickly become dated due to forest harvesting and land use conversion; therefore, these maps may not adequately reflect landscape properties and patterns relevant to current resource management and ecosystem studies. By updating an older land cover product (the 1993 Maine GAP map) using Landsat imagery and established forest change detection techniques, we demonstrate a practical and accurate means of providing contemporary, spatially explicit forest cover data needed to quantify landscape change. For a 1.8 million hectares study area in northern Maine, we quantify the accuracy of forest harvest classes and compare mapped harvest and regeneration area between the 2004 GAP update product and the 2004 Maine Landcover Dataset (MeLCD), a map recently developed in coordination with the 2001 National Land-Cover Database (NLCD). For the period 1995–2004, the overall harvest/non-harvest accuracy of the GAP update map is 87.5%, compared to 62.1% for the MeLCD. Producer and user accuracy for harvest detection is 92.4% and 89.7%, respectively for the GAP update, and 48.8% and 92.5% for the MeLCD. Mapped harvest area differs considerably, reflecting a systematic under-representation of recent harvest activity on the part of the MeLCD. By integrating older land cover data, the GAP update retains the forest disturbance legacies of the late 1970s through the early 1990s while simultaneously depicting 2004 forest composition for harvested and regenerating stands. In contrast, the MeLCD (and 2001 NLCD) over-represents the area and connectivity of older forest (undisturbed since the late 1970s), and provides no forest composition information for mapped forest regeneration. Systematic misclassification of forest age classes and harvest history has serious implications for studies focused on wildlife habitat modeling, forest inventory, and biomass or carbon stock estimation. We recommend the integration of older land cover data and time-series forest change detection for retention of harvest or disturbance classes when creating new forest and land cover maps.     

森林土壤N_2O产生与排放影响因子研究进展

影响森林土壤N2O产生和排放的主要因子为土壤理化性质(如土壤温度、土壤含水量、pH值以及土壤C/N等),同时,森林类型以及环境干扰(如氮沉降、土地利用/土地覆被变化等)也会影响土壤N2O产生和排放。文中首先论述了土壤N2O产生机制,然后综述了目前国内外关于上述影响因子对土壤N2O产生和排放影响的研究结果,最后提出未来应重点研究的方向。     

Hydrological impacts of afforestation — A review of research in India

We review the current status of experimental studies in India to understand the linkages between afforestation and hydrology. This discipline deals with the use and management of water, social awareness of environmental problems, and ecosystem limitations on provision of watershed services by river basins in the mountain regions of India. Our review begins with examination of experimental works in tropical countries and proceeds to discussion of initiatives of Indian research institutes and Government organizations towards establishing experimental watersheds to understand the impacts of land cover changes on hydrologic regimes in the Indian sub-continent. This is followed by the review of the experimental work carried out by various authors to assess the impact of land cover changes on major water balance components such as, runoff, groundwater, evapotranspiration and sediment yield. The spatial scales of these experiments have been limited to small watersheds or field plots. This paper also describes impacts of human interventions （such as planta- tions of exotic forest species to restore degraded landscapes） on the water balance components in diverse hydro-geo-environmental conditions in the Indian sub-continent. We focus on identifying the research areas which require immediate attention to develop tools to assist planners and policy makers in assessing and managing the water resources in these complex environments. The review is largely based on research results reported during the last 20 to 30 years.     

森林认证对森林转型的影响——来自发展中国家的经验证据

森林转型理论总结了长期以来各国实现森林恢复的影响因素与作用机制。20世纪90年代以来,森林认证作为促进森林可持续经营的市场机制在世界范围内逐渐展开。文中基于1990-2010年76个发展中国家的面板数据,运用分位数回归方法定量分析森林认证对森林转型的影响。研究结果表明,森林认证对森林面积和森林蓄积量都具有显著的正向影响,且在森林资源相对缺乏的发展中国家影响更大;研究还发现,人口密度和人均GDP对森林面积和森林蓄积量具有显著的负向影响,而造林面积、林产品进口额以及非初级产品出口比重等对森林面积和森林蓄积量都具有显著的正向影响。     

Challenges in developing and implementing a decision support systems (ETÇAP) in forest management planning: a case study in Honaz and Ibradı, Turkey

Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans.     

树种选择与配置对森林生态系统服务的影响

我国森林面积和蓄积量连续增长,但造林树种单一、林分幼龄化、径级持续偏小、单位面积蓄积量低。在气候变化挑战及全球经济一体化大背景下,如何发挥森林在木材生产、生物多样性保护、固碳、涵养水源及社会文化等方面的多重服务功能以满足经济社会发展对森林的多元化需求,是我国现代林业建设的当务之急。文中通过梳理国内外相关文献,分析不同树种与配置模式和不同森林经营选择对森林生态系统服务的影响,以及对森林生态系统服务影响的模拟预测方法与工具,进而总结当前研究与实践的总体趋势,以期为我国树种选择及其优化配置、增强森林生态系统服务功能提供决策参考。     

黄土高原和六盘山区森林面积增加对产水量的影响

[目的]定量评价黄土高原地区造林对流域产水量的影响,指导林水协调的林业发展和森林管理。[方法]综合分析多年在黄土高原、泾河流域、六盘山区开展的森林产流影响的多尺度研究结果。[结果]在黄土高原区域尺度,林地平均年径流(16 mm)比非林地(39 mm)减少59%;在典型流域尺度(泾河干流上游流域),森林年均产水量(76 mm)比自然草地减少51%,其中,半湿润土石山区的森林年均产水量(88.8 mm)比自然草地减少58%;在典型小流域尺度(半湿润的香水河小流域),完全覆盖森林后的年均产流比无森林覆盖情景减少59%。森林增加导致的年产流减幅在干旱地区和干旱年份会更大,并可能超过100%,如年降水量低于450 mm的黄土流域、半干旱的泾河上游黄土区的林地及半干旱的叠叠沟小流域的坡面乔木林分样地,其年产水量常为零或负值,即需消耗土壤水分和坡上汇入径流等维持生存。低度间伐不能显著减少森林蒸散耗水。[结论]在黄土高原研究的小流域、流域和区域空间尺度内,造林减少年产流量的平均幅度都在50%~60%以上,且随干旱程度的增加可达到100%,并因消耗降水外的其他水源而出现负产流。需依据水分承载力合理选择待恢复植被类型和确定森林覆盖率,这是保障区域供水安全和实现林水协调管理的基本途径。