应用遥感技术研究森林植被变化对河川径流的影响

本文应用遥感技术资料调查大流域不同年代的下垫面组成及其结构变化,结合流域历年实测的水文资料和对不同森林植被—土壤类型降雨截留、枯落物贮存、土壤孔隙贮水及土壤渗透性的测定,评价不同森林植被—土壤系统的涵水能力,研究森林植被覆盖率变化对河川径流的影响研究表明,河川径流总量受大气候的影响.流域森林植被的变化对河川径流的构成和年内分配有决定性作用,大流域森林的采伐和恢复对河川径流的影响是一个渐变的过程.     

大兴安岭森林火灾对河川径流的影响

采用单独流域实验法，利用长期定位观测数据，对森林火灾后河川径流的变化进行了研究。结果表明：大兴安岭特在森林火灾后，河川年轻流量明显增加，５月份融雪径流量有减少趋势。火烧后，森林对水分循环的调控能力减弱，径流的变化更加依赖于降雨。     

森林的采伐与更新对河川径流的影响

森林的采伐会增加径流的流失,而植树造林却有保持水份、改善气候,调节河水流量、防止土壤侵蚀等方面的作用,这是众所周知的事。我国森林亦不断的被采伐与更新,前些年份森林采伐有所增长,但是森林的采伐与更新对河川径流究竟有多大影响与如何发生影响却缺少这方面的试验研究资料。森林、植被与河川径流间的关系,与自然地理     

基于集水区法的森林生态系统影响径流研究进展

森林生态系统结构复杂, 具有减少地表径流、调节河川流量、减小土壤侵蚀等一系列保护环境的功能。森林植被变化对森林水文过程的影响会改变水量平衡方程的各个变量, 从而影响森林流域的水分分配和河川径流量, 进而对陆地生态系统水分循环起到重要的调节作用。从森林结构、森林类型、森林覆盖率和森林经营4个方面总结了国内外基于集水区法研究森林生态系统影响径流的结论, 即小流域的研究结果认为森林的减少将增加河川径流量, 而大流域的研究结果认为森林的减少将减少河川径流量。最后指出, 在研究单位和研究项目合作研究的基础上, 结合各相关学科的新兴技术和研究设备, 通过整合相关学科的研究成果, 阐明森林生态系统水土保持过程与机理, 是今后森林生态系统水文服务功能研究的发展方向。     

水源涵养林的功能与作用

森林调节了地圈中水循环速度,即调节了河川流量在时间上的不均匀,并有效的保护了山地土壤,因此可以说,在调解人类日常生活不可缺少的水的循环中,森林起着很大的作用。森林对水由地圈向气圈循环这一过程有密切关系,森林增加林区上空大气的水蒸汽数量,这对当地降水多少具有影响;森林对河川径流状况,具有直接关系,这种关系从局部地区看,意义可能不大;但对广大地区,因为森林参与了水循环,所以森林与水的关系是密切的。弄清广大地区的水循环过程与森林的关系,具有无可比拟的重要性。     

我国森林植被变化对河川径流影响的研究进展

依据成果,从河川年径流量、洪水径流以及枯水径流等方面介绍了国内有关森林植被变化对河川径流影响的研究进展,将目前已经得到的研究结论进行了归纳整理及分析,并对存在的问题和未来的工作重点进行了阐述。     

煤炭开采对山西省林业的影响

山西省是全国的煤炭大省,长期以来,煤炭开采严重破坏了山西的生态环境,其中对林业也造成了很大的影响。笔者在深入调研和查阅有关资料的基础上,分析认为采煤影响森林正常发育,大量侵占和破坏耕地,加大森林管护难度,过度消耗资源、降低了森林的生态效益,加大了造林难度、提高了造林成本,同时采煤还造成森林净化空气的承载力加大,河川径流减少,森林涵养水源能力下降等。     

祁连山大野口流域青海云杉林水文特征与生态因子关系研究

为了探讨青海云杉林水文特征与生态因子变化关系,选择大野口流域为试验流域,充分利用历史监测资料以及现有生态监测设施仪器的优势,通过降水、林冠及树干截留、苔藓枯落物截留、土壤水分及温度、积雪消融、冻土冻融、土壤蒸发、河川径流、林分立地条件、林分气象因子、林分结构、苔藓枯落物结构、土壤特性等指标监测,采取特征参数统计、多元函数回归和相关系数等分析方法,研究了水文特与生态因子之间的相互关系。研究结论为:(1)建立了水位与河川径流量之间的回归关系,探讨了祁连山大野口流域河川径流量变化规律;(2)建立了气温、降水、土壤温度、冻土冻融、积雪消融等因子与河川径流之间的相互关系,得出了气温、降水与河川径流的变化趋势;(3)得出了苔藓、枯落物、土壤水热特征以及土壤特性与土壤蒸发之间的生态因子关系。研究结论为山地森林和水资源生态保护与建设提供科学依据和参考。     

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。     

森林的采伐与更新对河川径流的影响(续)

三、试验成果与讨论(一) 北卡罗来纳州Coweeta试验站1、二次皆伐的Ws13流域本流域的树木于1940年被全部采伐后,河川径流增加362毫米,高于预测径流的65%;重新生长23年后1963年再次全部采伐,第二次采伐后河川径流增长375毫米,高于预测径流的40%,在每次采伐后河川径流开始时大增,以后逐渐下降,二次皆伐后河川径流增加与时间的关系曲线如图2所示。图2中1966～1969年径流量的增加低于平均曲线,1974～1977年径流量增加却高于     

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。     

Influence of floods on natural riparian forests along the Ergis River, west China

The riparian forests along the Ergis River, west China, composed mainly of Salicaceae species, play an important role in eco-environment protection and sustainable development of local agriculture, stockbreeding, and social economy of the northern desert region of Xinjiang Uygur Autonomous Region. The study of the influence of floods on the natural riparian forests is imperative for the understanding of the successional process and the acceleration of conservation and restoration of forests. By investigating the relationship between floods and dispersal of seeds, sprouting, natural regeneration, the structure of the forests, and their current distribution, we conclude that: 1) the ripening and dispersal periods of Salicaceae species seeds overlap largely with flood occurrence periods, and the sprouting and natural regeneration of seeds depend greatly on flood events; 2) floods supply soil water and increase groundwater level of riparian land through flood irrigation and horizontal infiltration to maintain the normal growth of the riparian forests; 3) floods have a decisive influence on the structure, composition, and distribution pattern of riparian forests, and any disturbance in the water flow has a profound effect on these characteristics. Given these facts, some management measures for conservation and restoration of the riparian forests are proposed, including the establishment of riparian forest buffer belt, bank stabilization measures, and maintenance of flood protection. __________ Translated from Journal of Beijing Forestry University, 2006, 28(2): 46–51 [译自: 北京林业大学学报]     

Distance to flood meadows as a predictor of use of <Emphasis Type="Italic">Nothofagus pumilio</Emphasis> forest by livestock and resulting impact,in Patagonia,Argentina

Seedling browsing by livestock has been indicated as major threat for forest sustainability use. Nothofagus pumilio forests are part of the livestock raising system in Patagonia, but because of the sparse understory cover, livestock graze mainly on flood meadows within the forest matrix. The complexity of the environment under study (forests and flood meadows) means that an adaptive predictor is needed to evaluate the intensity of resource use by livestock in order to assess its effect on the forest. Distance to flood meadows was evaluated as a predictor of the use intensity of the forest by livestock and its effect on the understory. The study was conducted at three sites in Chubut Province, Patagonia–Argentina. We established transects in the forest 320 m long, starting at the edge flood meadow-forest. In these transects, the livestock presence indicators (soil compaction, density of feces and trails) and composition of the understory were evaluated. Generalized Linear Model for repeated measures for longitudinal data were used. The indicators showed that distance is efficient for estimating forest use intensity by livestock. The understory varied with distance, the cover of exotic herbaceous was higher near the flood meadow. Far from the flood meadow, the cover was entirely composited of native species. The results support the use of distance to flood meadows as a tool for decision making in livestock and forest management in N. pumilio forests, and for further research on livestock effect on the forest.     

闽江流域洪灾与森林生态环境的研究Ⅰ.闽江流域洪灾成因与森林的水文效应

通过收集大量闽江流域气象、地质、土壤、水文、水系、森林资源和人类活动等资料 ,揭示了闽江流域洪灾的成因 :自然条件 (即异常气候和蒲扇形水系等 )是直接原因 ,人类不合理的活动造成的水土流失 ,河床抬高 ,流域蓄洪能力下降 ,特别是森林资源质量的下降 ,引起的保土蓄水和阻洪滞洪功能的严重削弱 ,是根本原因。同时也分析了森林与水文的关系 ,揭示了森林在防灾减灾中的作用。     

抚仙湖流域磷矿区主要植物群落水土保持效应研究

通过对抚仙湖流域磷矿开采区8种主要植物群落类型水土保持效应的研究，探讨了不同植物群落的抗径流和土壤侵蚀的能力以及与土壤抗蚀性之间的关系；筛选出水土保持效应较优的植物群落。研究表明：竹林群落和旱冬瓜林群落的抗径流能力和抗土壤侵蚀能力较强，可作为该地水土保持的先期植物群落。荒草地和矿渣废弃地水土流失严重，土壤抗侵蚀性差，应进行植树造林和加强封育管理。云南松林、华山松林、桉树林、灌木林的土壤抗侵蚀性稍逊于竹林和旱冬瓜林，营造水土保持防护林时可适当考虑。     

The value of the flood control service of tropical forests: A case study for Trinidad

To date there have been only few case studies that specify how hydrological processes regulated by forests convey into benefits for society. The objective of this paper is to analyse the relation between forest cover and the reduction of flood risks on Trinidad. Our hypothesis is that the relation between forest cover and flood control is non-linear, in other words that deforestation of a watershed will increase flood risks in a non-linear way. This implies that the per hectare value of the hydrological service is determined in part by the remaining forest cover of the catchment. We find that this varies strongly between watersheds, between 16 and 268 US $ per hectare per year. Our results demonstrate a non-linear relationship between catchment's forest cover and the generation of the flood control service, and indicate that even small levels of deforestation can lead to a significant increase in flood risks in Trinidad.     

Litterfall production in forests located at the Pre-delta area of the Paraná River (Argentina)

? The objectives of this study were to measure litterfall production of the four floodplain forest types and to analyze the relationship between litterfall (forest type, dominant species, and organic fractions) and flood pulses.

? Litterfall production was measured in two mono-specific stands of Salix humboldtiana or Tessaria integrifolia, respectively, and two mixed forests dominated by A. inundata or Nectandra angustifolia, during 1998 and the 2000–2002 periods.

? Mono-specific stands presented similar productivities (6.8 and 6.5 Mg dry matter ha^?1 y^?1, respectively), but differed significantly from the two other. The highest litterfall production was obtained during the large flood that occurred during 1998, decreasing later throughout the study period. Leaves were the dominant fraction of litterfall, followed by branches, flowers, and fruits.

? Only S. humboldtiana, T. integrifolia and A. inundata forests showed distinct patterns of litterfall production, depending on the flooding pulse. N. angustifolia did not show a distinctive litterfall pattern.

? The forests studied here presented patterns of litter production associated with the flood pulse according to its location along a topographic gradient, that controls the litter productivity of these forests.

     

Effects of reforestation on the hydrological function of a small watershed in the Three Gorges Reservoir Area

For vegetation communities with hydrological function in the Three Gorges Reservoir Area, the storm event distributed hydrological model Precipitation-Runoff Modeling System (PRMS)-Storm was built based on modular modeling system developed by the US Geological Survey, and was employed to study the effects of forests on peak flows in the Xiangshuixi forest watershed in the Three Gorges Reservoir Area. The results showed that: 1) this simulation study suggested that PRMS-Storm can meet the second level national flood prediction standards of China for simulating storm events of small forest watersheds, and can issue flood forecasting; 2) hydrological functions of different vegetation communities were evaluated, and three simulation scenarios were arranged: mixed conifer-broadleaf forests (scenario 1), broad-leaved forests (scenario 2), and general forests arrangement (scenario 3); 3) the well-arranged forest scenarios can reduce over 20% of surface runoff, result in an increase of over 16% in subsurface flow, and decrease peak flow by 20.8%, 9.6%, and 18.9%, respectively. The reduction of peak flow rates was significant when rainfall peak was higher than 0.8 mm/min, especially for short-term rainfall events. In general, we found that scenarios 1 and 3 were preferable for reducing peak flow rates and volumes in the reforestation practices in the study region, and scenario 1 was better than scenario 3, so the mixed conifer-broadleaf forests had the best hydrological function. __________ Translated from Journal of Beijing Forestry University, 2006, 28(5): 42–51 [译自: 北京林业大学学报]     

Structure, reproduction and flood-induced dynamics of riparian Tugai forests at the Tarim River in Xinjiang, NW China

Tugai forests are the riparian forests along the rivers in thecontinental desert regions of Central Asia, i.e. the Tarim River,Amu Darya and Syr Darya. They mainly consist of Populus euphraticaOliv., Populus pruinosa Schrenk. and Elaeagnus oxycarpa Schltdl.As a consequence of land opening campaigns, large areas of Tugaiforests were destroyed after the 1950s. Due to excessive useof water for irrigation, the remaining Tugai forests are undersevere threat. Near natural Tugai forests still exist alongthe Tarim middle reaches in the Tarim Huyanglin Nature Reserve,Xinjiang, NW China. There is a gap in understanding, how theseedlings of P. euphratica establish as trees which continuouslyconnect to the groundwater. Therefore, the set of conditionswhich must be met for germination and successful establishment,i.e. formation of Tugai forests, was investigated along a representativetransect still under natural conditions. P. euphratica seedlingsgerminate in belts during the retreat of the summer flood onfreshly deposited sites bare of other vegetation. Such germinationsites are formed by river dynamics. While germination takesplace regularly in the study area, successful establishmentis restricted to few germination events. Seedlings face droppinggroundwater levels during spring and early summer of the secondyear after germination. Therefore, for successful establishment,it is essential that the flood of the second year starts intime and is high enough, in order to replenish the groundwater.Furthermore, clayey soil layers in the subsoil may play a rolefor successful establishment, too, as they store water betterthan sandy soil layers.     

森林治水与奥地利荒溪治理

国际公认奥地利林业治山防、抗灾害是成功的。其核心思想是，森林生物措施与措施相结合，进行综合治理。作者着重介绍了奥地利林业治山经费来源、组织实践及其科研系统。Ａｕｌｉｔｚｋｙ教授调查蒂罗尔州９个村庄，通过２００多年的数据对比分析，证明森林消失与恢复对荒溪的扩大与缩小有着直接影响。