共查询到19条相似文献,搜索用时 218 毫秒
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由于受多种因素影响,我国的环境污染还比较严重。研究表明,森林生态系统在保持水土、涵养水源、增加碳汇、净化空气等方面具有显著效应。森林生态系统对重金属的净化效应已成为研究热点之一。文中综述了森林生态系统林冠层、凋落物层和土壤层对降水过程中重金属浓度和形态的影响规律,分析森林生态系统水文过程中重金属富集和释放的影响因子;并在此基础上总结目前研究中存在的主要问题,指出今后应重点开展长期、系统的定位研究,深入探索森林对重金属污染的净化功能和净化机制,加强重金属对生物的影响研究,重视气候变化背景下森林对降水过程中重金属的响应与净化效应,以期为精确评价森林环境效应提供参考。 相似文献
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森林水文学过程中的水质分析 总被引:2,自引:0,他引:2
<正> 水是林木赖以生存的基本要素之一,也是森林生态系统物质循环中最重要的一种物质。大气降水则是树木生长所需水分的主要来源。在大气中浮游的尘埃微粒,伴随着降水而进入森林生态系统,是大气降水进入森林生态系统的营养物质,尽管其含量很低,但长年累月随雨水输入使它们成为生物地球化学循环的重要组成部分。因此,准确分析森林水文学各个过程中的养分含量,对于研究一个系统的养分输入、输出,以及评价养分循环是必不可少的。近五年来,我们对我院会同森林生态系统 相似文献
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我国主要森林生态系统类型降水截留规律的数量分析 总被引:92,自引:0,他引:92
通过对大量林林生态系统水文生态功能研究资料的分析,从林冠层、枯枝落叶层和土壤三个森林水文生态功能的发挥最主要的层次出发,比较分析了我国主要森林生态系统类型的降水截留规律。 相似文献
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林下植被多样性、生物量及养分作用研究进展 总被引:3,自引:2,他引:1
林下植被是森林生态系统的重要组成部分,对森林生态系统的稳定性、生产力及养分循环具有重要影响,因此研究林下植被具有重要意义。但是以往由于研究方法、研究时限以及研究尺度等方面存在许多缺陷,对林下植被的认识还不统一,研究结论不够深刻。如何正确测定林下植被多样性及其生物量,合理评价林下植被对森林生态系统的作用,科学制定林下植被的管理措施,这些问题都值得进一步深入研究。文中对林下植被多样性、生物量及其养分作用3个方面的研究进行了分析总结,以期为今后林下植被研究、林下植被管理和森林可持续经营提供参考。 相似文献
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Julio Campo Juan F. Gallardo Guillermina Hernández 《European Journal of Forest Research》2014,133(1):121-129
We compared the N and P contents of the main labile components of nutrient cycles in three different forest ecosystems [a tropical evergreen forest (TEF); a tropical dry forest (TDF); and a Mediterranean temperate forest (MTF)] with low P supply. A mass-balance approach was used to estimate mean residence times for organic matter, N and P in the forest floor, and to examine the flexibility of N and P intra-system cycling in the three forest ecosystems. For this purpose, we combined published values of N and P in foliage, litterfall, forest floor litter and mineral soils in these three forest ecosystems. The results of our analysis were consistent with the widely held belief that the N content of leaves (both green and senescent) and litter increases with increasing temperatures. In contrast, the data did not support the hypothesis that leaf P content decreases with increasing temperatures and precipitation: leaf and litterfall P contents were higher in both tropical forests than they were in the temperate forest. The TEF had the highest P content of the three forests studied. The mass-balance analysis indicated that although P mineralization in the TDF can run ahead of litter decomposition stoichiometry when P is in short supply, flexibility is much reduced or absent in the TEF and the MTF. Our analysis provides additional evidence of the importance of climatic factors in forest ecosystem processes and highlights the role of flexibility in ecosystem nutrient cycling, especially for P in ecosystems with a limited P supply. 相似文献
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森林生态系统的土壤碳储量是陆地生态系统碳库的重要组成部分。土壤呼吸则是土壤碳库参与陆地碳循环的主要方式,其受到诸多生物和非生物因子的综合调控。偶发性降雨会引起森林土壤湿度的瞬间增加,进而导致土壤呼吸速率的快速提高。文中介绍了森林土壤呼吸及其组分,综述了降雨脉冲效应的特征和诱导机制(包括物理替代机制、微生物代谢机制、土壤养分限制机制及光化学调控机制等),分析了当前降雨脉冲研究存在的不足并展望了未来的研究重点,认为森林生态系统是未来开展降雨脉冲效应研究的重要方向,探究森林土壤呼吸不同组分对降雨脉冲的响应差异与机制也是潜在的重要研究方向。 相似文献
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林下植被组成和功能研究进展 总被引:3,自引:0,他引:3
林下植被作为森林生态系统的一个重要组成部分, 在维护森林多样性、推动森林生态系统流程和功能中扮演着重要的角色。目前, 关于林下植被的研究已有上百年历史, 其中在森林群落分类、更新演替、养分循环及稳定生产力等方面做了大量研究。文中从林下植被的定义及其组成、演替和功能等方面综述了近年来林下植被的研究进展, 并探讨了如何综合研究演替以及干扰对林下植被组成的影响、林下植被对气候变化的可能响应以及如何将林下植被作用及功能的研究理论应用于近自然人工林建设和管理实践中。 相似文献
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森林生态系统碳循环研究的模型方法 总被引:1,自引:0,他引:1
森林生态系统碳循环是陆地碳循环研究中的重要内容,碳循环模型已成为研究森林碳循环的必要方法.其中气候变化、大气CO2 浓度上升及CH4的生成导致森林生态系统在结构、功能、组成和分布等方面的变化及其反馈关系对森林生态系统碳循环的影响是模型模拟的关键问题.碳循环模型可用经验模型、机理模型和混合模型的建模方法.目前森林生态系统碳循环模型的发展趋势为:综合生物地理模型和生物地球化学模型的特点建立区域动态碳循环模型;从单一碳循环模拟向碳、氮、磷等多种元素循环相耦合的模拟;碳循环模型与遥感、GIS 技术结合,模拟大尺度的碳循环过程;CH4生成及对森林碳循环的影响方面的研究. 相似文献
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林火干扰作为森林生态系统中能量传递和养分循环的重要因子,对于研究火烧迹地植被更新与快速恢复可提供一定的数据理论支撑,而林火干扰对土壤微生境及微生物氮循环的影响机制一直是广大学者研究的热点。文中从火烧强度、恢复时间、火烧木管理方式等3个方面总结国内外林火干扰对土壤氮组分及氮循环的影响研究进展,揭示了林火干扰和全球气候变化对土壤氮循环的短期及长期影响机制,探讨不同生物技术在林火干扰下土壤微生物氮循环基因丰度变化中的应用;提出未来林火干扰对森林生态系统土壤氮循环影响的研究展望:1)全面比较研究不同林火干扰模式对土壤氮组分、微生物氮循环的影响;2)研究评价不同林火干扰模式下土壤氮库的稳定性;3)加强高通量测序、定量PCR技术、宏基因组学、稳定同位素探测等技术在林火干扰与气候变化对森林生态系统影响研究中的应用。研究结果对火烧迹地植被更新、土壤氮库的重建与功能发挥具有重要意义。 相似文献
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《Forest Ecology and Management》1999,114(1):31-43
The low nutrient supply of heathland soils is often insufficient for the nutrient demand of growing forests and woodlands, and additional atmospheric input of nutrients is beneficial for the tree growth. On old heathland soils tree species influencing nutrient input with regard to higher amounts have competitive benefits on the early stages of succession and/or as first planted trees with consequences for both the successional development and the nutrition and management of heathland and forests. In three stages of heathland forest succession on highly acidified and nutrient poor soil, the influence of the canopies of a Calluna heathland, a pioneering birch-pine woodland, and a terminal oak-beech forest on nutrient input was investigated. Of all investigated species Scots pine has the highest interception of water and nutrients (N, K, Ca, Mg). As a consequence, the nutrient input into the pioneering birch-pine forest is the highest of the three types of ecosystems. This ability to meliorate the nutrient supply by increasing the nutrient input favours pine in the early stages of the succession. The enhanced nutrient input and accumulation within the young successional forest ecosystems involves two different succession and/or management considerations depending upon the further ecosystem development.
- 1.The increasing nutrient availability mitigates the negative influence of the highly acidified nutrient poor soil on the growth of oak and beech and facilitates the conversion of pine dominated woodlands and forests into forests dominated by broadleaved species.
- 2.For regeneration of heathland from naturally established pine woodlands and forests, deforestation have to be combined with techniques of nutrient impoverishment of the soil.
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Decreasing the forest ecosystem leaf-area index error(LAIe)helps accurately estimate the growth and light energy utilization of aboveground foliage.Analyzing light transmission in forest ecosystems can effectively determine LAIe.The LAI-2200 plant canopy analyzer(PCA)is used extensively for rapid field-effective LAI(LAIe)measurements and primarily to measure forest canopy LAIe values.However,sometimes this parameter must also be measured in forests with small clearings.In this study,we used the LAI-2200 PCA to obtain one A-value and four B-values each for the canopy,herbaceous layer,and forest ecosystem LAIe.Field measurements showed that the three LAIe types were obviously different.In certain quadrats,the average herbaceous layer(Dicranopteris dichotoma Bernh.)LAIe apparently exceeded that of the Pinus massoniana forest ecosystem.The sources of this error were measuring and recording A-value readings for small canopies and underestimating the ecosystem LAIe.We obtained similar coefficients of determination for both the pre-recomputation and post-recomputation of the canopy and forest ecosystem LAIe(R^2C 0.96 and R^2C 0.99,respectively);thus,the error was decreased.Measuring field LAIe with the LAI-2200 PCA and recomputation should compensate for LAIe underestimation in complex forest ecosystems. 相似文献
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