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1.
Based on the model–data comparison at the eddy-covariance observation sites from CarboEastAsia datasets, we report the current status of the terrestrial carbon cycle modeling in monsoon Asia. In order to assess the modeling performance and discuss future requirements for both modeling and observation efforts in Asia, we ran eight terrestrial biosphere models at 24 sites from 1901 to 2010. By analyzing the modeled carbon fluxes against the CarboEastAsia datasets, the strengths and weaknesses of terrestrial biosphere modeling over Asia were evaluated. In terms of pattern and magnitude, the carbon fluxes (i.e., gross primary productivity, ecosystem respiration, and net ecosystem exchange) at the temperate and boreal forest sites were simulated best, whereas the simulation results from the tropical forest, cropland, and disturbed sites were poor. The multi-model ensemble mean values showed lower root mean square errors and higher correlations, suggesting that composition of multiple terrestrial biosphere models would be preferable for terrestrial carbon budget assessments in Asia. These results indicate that the current model-based estimation of terrestrial carbon budget has large uncertainties, and future research should further refine the models to permit re-evaluation of the terrestrial carbon budget.  相似文献   

2.
Gross primary productivity (GPP) is a major component of carbon exchange between the atmosphere and terrestrial ecosystems and a key component of the terrestrial carbon cycle. Because of the large spatial heterogeneity and temporal dynamics of ecosystems, it is a challenge to estimate GPP accurately at global or regional scales. The 8-day MODerate resolution Imaging Spectroradiometer (MODIS) GPP product provides a near real time estimate of global GPP. However, previous studies indicated that MODIS GPP has large uncertainties, partly caused by biases in parameterization and forcing data. In this study, MODIS GPP was validated using GPP derived from the eddy covariance flux measurements at five typical forest sites in East Asia. The validation indicated that MODIS GPP was seriously underestimated in these forest ecosystems of East Asia, especially at northern sites. With observed meteorological data, fraction of photosynthetically active radiation absorbed by the plant canopy (fPAR) calculated using smoothed MODIS leaf area index, and optimized maximum light use efficiency (ε max) to force the MOD17 algorithm, the agreement between predicted GPP and tower-based GPP was significantly improved. The errors of MODIS GPP in these forest ecosystems of East Asia were mainly caused by uncertainties in ε max, followed by those in fPAR and meteorological data. The separation of canopy into sunlit and shaded leaves, for which GPP is individually calculated, can improve GPP simulation significantly.  相似文献   

3.
气候变化与森林生态系统:影响、脆弱性与适应性   总被引：6，自引：1，他引：5  
综述近年来国内外有关气候变化与森林生态系统的相关研究方法与结果,总结已观测到的气候变化对森林物候、森林生产力、森林结构、组成和分布,以及森林碳库的影响,以及未来气候变化可能产生的影响;并对气候变化条件下森林生态系统的脆弱性和适应性评估方法进行总结评述.对目前相关研究的不确定性及存在的问题进行分析,强调未来需要加强的研究领域.  相似文献   

4.
Flux data are noisy, and this uncertainty is largely due to random measurement error. Knowledge of uncertainty is essential for the statistical evaluation of modeled and measured fluxes, for comparison of parameters derived by fitting models to measured fluxes and in formal data-assimilation efforts. We used the difference between simultaneous measurements from two towers located less than 1 km apart to quantify the distributional characteristics of the measurement error in fluxes of carbon dioxide (CO2) and sensible and latent heat (H and LE, respectively). Flux measurement error more closely follows a double exponential than a normal distribution. The CO2 flux uncertainty is negatively correlated with mean wind speed, whereas uncertainty in H and LE is positively correlated with net radiation flux. Measurements from a single tower made 24 h apart under similar environmental conditions can also be used to characterize flux uncertainty. Uncertainty calculated by this method is somewhat higher than that derived from the two-tower approach. We demonstrate the use of flux uncertainty in maximum likelihood parameter estimates for simple physiological models of daytime net carbon exchange. We show that inferred model parameters are highly correlated, and that hypothesis testing is therefore possible only when the joint distribution of the model parameters is taken into account.  相似文献   

5.
对普洱市太阳河自然保护区的地文景观、水域景观、动植物景观、气候景观、人文景观等景观资源进行分析评价,提出观景台、科考中心、国际狩猎场、生态果园、骑马、森林徒步探险、水上游憩等森林生态旅游开发项目,并作了市场细分与定位,市场现状分析及前景预测。  相似文献   

6.
森林生态定位观测系统网络管理平台设计与实现   总被引：1，自引：1，他引：0  
森林生态系统观测数据是重要的生态研究及环境保护数据。随着观测系统日趋复杂及监测数据量逐渐增多,对森林生态系统定位观测网络数据管理和共享存在着许多问题。为了方便数据存储、及时共享信息和易于挖掘数据隐藏信息,文中基于B/S模式,采用Jquery框架及MongoDB+Sqlserver存储架构建设森林生态定位观测系统网络管理平台,实现我国森林生态定位观测系统的网络可视化管理。平台具有地图可视化展示、数据实时观测及统一管理、数据可视化分析与共享等功能。在新疆西天山国家级自然保护区进行了系统应用,收到良好效果。使用该平台可以实现全国森林生态站信息的规范系统化汇集、网络可视化管理和云存储共享服务的目标,具有广泛的推广应用价值。  相似文献   

7.
各森林生态站通过开展各种实验、观测和研究,积累了海量的、格式多样的观测数据,但是由于处理手段的落后,这些数据所蕴含的有用信息并没有被完全揭示出来,每个森林生态站都是一个信息孤岛,各森林生态站之间缺乏信息的共享;另外单纯的观测结果数据库并不能直观地反应观测样地以及样地的其他背景特征。因此,本文提出了建立基于WebGIS的森林生态站信息管理系统。本系统基于超图公司的最新网络GIS平台,解决了森林生态站数据管理手段落后以及在较大范围内难以进行信息共享的问题。  相似文献   

8.
Forests play an important role in carbon sinks and mitigation of atmospheric concentrations of carbon dioxide and greenhouse effect. Given that sample plots used for collection of forest carbon observations are often much smaller than the map units of forest carbon at regional, national, and global scales, scientists are currently experiencing two challenges. The first challenge is to produce reliable maps of forest carbon using the data from inconsistent sizes of plots and image pixels. Also, because estimates of forest carbon normally contain uncertainties, the second challenge is to accurately model propagation of uncertainties from input data to output results. In this study, a methodology for mapping and analyzing spatial uncertainty of forest carbon estimates was developed to address these challenges. The methodological framework consisted of two methods. The first one was up-scaling method that combined and scaled up existing national forest inventory plot data and satellite images from smaller sample plots and image pixels to larger map units. The second one was spatial uncertainty analysis and error budget method that entailed modeling propagated uncertainties through a geostatistical mapping system. A case study using 46 permanent national forest inventory plots from Wu-Yuan County, Jiangxi, China, was undertaken to test this methodology. The results showed that this method reproduced not only the spatial distribution of forest carbon but also the spatial pattern of variances of its estimates and was able to quantify the contributions of uncertainties from the field plot data and satellite images to the uncertainties of forest carbon estimates. Thus, this study, to some extent, overcame the gaps that currently exist in the generation and assessment of forest carbon estimation maps. Moreover, the results showed that in this case study, the variation of the band ratio defined as (TM2 + TM3 + TM5)/TM7 contributed more uncertainties to the estimates of forest carbon than the variation of the plot data. In addition, we also found out that the product of the input plot forest carbon variance and the band ratio variance, implying the interaction between these two variables, reduced the uncertainties of the forest carbon estimates.  相似文献   

9.
德国奥地利森林资源监测与经营管理的特点及启示   总被引：6，自引：1，他引：5  
深入分析了德国在同一抽样体系下,实施森林资源及其生态状况监测的技术特点、永续利用的经营理念与近自然的经营管理方法,以及奥地利信息技术在森林资源监测中的应用特点与科技创新的发展措施,对比我国森林资源监测状况,提出了完善森林资源监测内容和指标体系,建立森林资源及生态状况综合监测体系,加强新技术的创新研究和应用,积极争取国家基础数据共享应用的建议。  相似文献   

10.
基于中国陆地生态系统通量观测研究网络（ChinaFlux）3年（2005．2007年）的观测数据,研究了千烟洲中亚热带人工林（QYF）和长自山温带混交林（CBF）的气体调节通量动态和气体调节价值累积过程。本文将气体调节服务区分为植被气体调节服务和净生态系统气体调节服务。采用碳税法、造林成本法和工业制氧法对气体调节服务价值化,研究表明气体调节通量具有显著的季节变化。千烟洲人工林和长白山混交林植被的日均CO2吸收量分别为82．00kg·hm^-2·d和59．37kg·hm^-2·d,对应的O2通量分别为59.65kg·hm^-2·d和43．19kg·hm^-2·d。千烟洲人工林和长白山混交林的植被气体调节价值累积过程曲线均为S型,年均植被气体调节服务价值分别为14342．69元·hm^-2和10384．18元·hm^-2。就净生态系统气体调节服务而言,千烟洲人工林全年各月均表现为CO2的净吸收和O2的净释放,而长白山混交林则主要在5-9月表现为CO2的净吸收。千烟洲人工林的净生态系统气体调节价值累积过程曲线为S型,而长白山混交林则为单峰型。千烟洲人工林和长白山混交林的年均净生态系统气体调节服务价值分别为8470．52元·hm^-2和5091．98元·hm^-2。植被气体调节服务和净生态系统气体调节服务主要发生为5-10月。  相似文献   

11.
More than half of the forest land in Bavaria belongs to private forest owners, who contribute a large amount of the industrial timber supply. The level of information about private forests is in comparison to the communal forests inadequate. The increasing demand for data about the forest sector in Bavaria can be partially covered by regular inventories but requires supplementary monitoring activities. Regular surveys based on voluntary participation deliver data, but often do not fulfil statistical requirements due to low response rates of 15–20% to postal surveys. The Bavarian annual postal cutting survey has been built up over 5 years using a roster of voluntary participants. This pragmatic and cost-effective approach provides reliable data for statistical purposes and gives insight in the forest management activities of small-scale forest owners. Recent technical developments, in particular the availability of grids and digital land-use maps, facilitate the random sampling of forest owners. This approach has been applied in a climate change project, but the results did not meet the expectations because of low response rates. The rather labour- and cost-intensive census of forest owners as applied in the project in Eastern Bavaria cannot be recommended except in exceptional circumstances. In the described project a qualitative approach with four distinct questionnaires has been adopted in order to identify ways to reach forest owners that are either not interested in their forests or do not respond to requests. Due to low response rates the objectives of the study could only be partially achieved.  相似文献   

12.
We modeled the effects of climate change and two forest management scenarios on wood production and forest carbon balance in French forests using process-based models of forest growth. We combined data from the national forest inventory and soil network survey, which were aggregated over a 50 x 50-km grid, i.e., the spatial resolution of the climate scenario data. We predicted and analyzed the climate impact on potential forest production over the period 1960-2100. All models predicted a slight increase in potential forest yield until 2030-2050, followed by a plateau or a decline around 2070-2100, with overall, a greater increase in yield in northern France than in the south. Gross and net primary productivities were more negatively affected by soil water and atmospheric water vapor saturation deficits in western France because of a more pronounced shift in seasonal rainfall from summer to winter. The rotation-averaged values of carbon flux and production for different forest management options were estimated during four years (1980, 2015, 2045 and 2080). Predictions were made using a two-dimensional matrix covering the range of local soil and climate conditions. The changes in ecosystem fluxes and forest production were explained by the counterbalancing effect of rising CO2 concentration and increasing water deficit. The effect of climate change decreased with rotation length from short rotations with high production rates and low standing biomasses to long rotations with low productivities and greater standing biomasses. Climate effects on productivity, both negative and positive, were greatest on high fertility sites. Forest productivity in northern France was enhanced by climate change, increasingly from west to east, whereas in the southwestern Atlantic region, productivity was reduced by climate change to an increasing degree from west to east.  相似文献   

13.
国庆喜 《林业研究》2001,12(2):93-96
大小兴安岭是我国纬度最高的地区，也是我国近百年来温度增加最明显的区域。大小兴安岭森林植被交错区位于东经123°～128°，北纬48°～53°之间。作为温带针阔叶混交林向寒温带针叶林的过渡区域，在全球变化研究中占有重要地位。本文对该交错区的地理位置、地形地貌、气候梯度、土壤类型、植被类型等进行了论述。  相似文献   

14.
Change in potential natural vegetation (PNV) distribution associated with climate change due to the doubling atmospheric carbon dioxide (2×CO2) was estimated with a global natural vegetation mapping system based on the modified Kira scheme to the globe and the continents. With an input of widely-distributed global climate data, the system interpolates data onto a 1° latitude by 1° longitude grid over the globe, generates estimates of vegetation type, and produces a composite PNV map. The input climate data corresponding to the 1×CO2 and 2×CO2 consists of observations prior to AD 1958 at 2,001 weather stations worldwide and the 2×CO2 simulation output from the Japan Meteorological Research Institue's General Circulation Model, respectively. As a result of the simulated global warming, the vegetation zones expanded mostly from the tropics toward the poles. PNV area changed by 6.98 billion (G) ha of the total land area (15.04 Gha) and potential forest area corresponding to the closed forest and open forest (woodland) reached 9.74 Gha with the increase of 1.29 Gha. The potential forest area in Europe had obvious advantages to the climate change accompanied with the increase of actual forest area. Although the actual forest area has decreased in North America and Asia, the potential forest area in these continents also benefitted from the climate change. In the end, the remaining continents tended to bear the brunt of the climate change.  相似文献   

15.
温室效应、全球变暖与林业   总被引：20，自引：0，他引：20  
本文综述了当前受到国内外普遍重视的全球变暖和气候变化以及与林业有关的问题。简要介绍了目前对森林在全球碳平衡中的作用, 气候变化可能对林业的影响, 以及林业对策的研究现状和展望。  相似文献   

16.
Abstract

Forest carbon sinks significantly contribute to mitigation of atmospheric concentrations of carbon dioxide. Thus, estimating forest carbon is becoming important to develop policies for mitigating climate change and trading carbon credits. However, a great challenge is how to quantify uncertainties in estimation of forest carbon. This study investigated uncertainties of mapping aboveground forest carbon due to location errors of sample plots for Lin-An County of China. National forest inventory plot data and Landsat TM images were combined using co-simulation algorithm. The findings show that randomly perturbing plot locations within 10 distance intervals statistically did not result in biased population mean predictions of aboveground forest carbon at a significant level of 0.05, but increased root mean square errors of the maps. The perturbations weakened spatial autocorrelation of aboveground forest carbon and its correlation with spectral variables. The perturbed distances of 800 m or less did not obviously change the spatial distribution of predicted values. However, when the perturbed distances were 1600 m or larger, the correlation coefficients of the predicted values from the perturbed locations with those from the true plot locations statistically did not significantly differ from zero at a level of 0.05 and the spatial distributions became random.  相似文献   

17.
我国林火监测体系现状分析   总被引：4，自引：0，他引：4  
森林火灾是一种世界性的林业重大灾害,我国每年都有上千次的森林火灾发生,造成严重的森林资源破坏、经济和财产损失。文章从空间范围角度将我国目前的林火监测体系分为卫星监测、航空巡护、近地面观测(瞭望塔观测和视频监控)和地面监测四种主要监测形式,并介绍了各种林火监测方法,同时对四种林火监测手段各自的优缺点进行了比较,最后结合目前出现的新技术与新方法对未来林火监测体系的发展趋势进行了展望。  相似文献   

18.
Tropical forests are at the center of any global debate on climate change and sustainable forest management because of their twin roles in climate change adaptation and mitigation and for resilient development. However, in the countries of the Congo Basin forests receive very little attention in national planning and policies. Climate change is not currently considered in decisions and long-term forest management plans in these countries. This paper demonstrates that: (1) Congo Basin forests are needed for adaptation because they can help to decrease human vulnerability to climate change; and (2) Congo Basin forest management practices need to be adapted to accommodate climate change because these forests are vulnerable to climate change. A framework for facilitating adaptation in forestry is discussed and a review of adaptive actions presented. The paper recommends the adoption of sustainable forest management approach that includes a climate change focus. Such management should not only avoid any adverse effects on the forest resources and conservation of biodiversity, but also provides opportunities for greater, more sustainable rural development and poverty alleviation through income generation and employment opportunities.  相似文献   

19.
Review of literature indicates that many uncertainties and assumptions exist in predicting the impacts of a climate change on forest ecosystems. However, current knowledge is sufficient to encourage any measures that are combating climate change, that is to reduce first and foremost the release of harmful substances to the atmosphere, lithosphere and biosphere.  相似文献   

20.
Greenhouse gas emissions have significantly altered global climate, and will continue to do so in the future. Increases in the frequency, duration, and/or severity of drought and heat stress associated with climate change could fundamentally alter the composition, structure, and biogeography of forests in many regions. Of particular concern are potential increases in tree mortality associated with climate-induced physiological stress and interactions with other climate-mediated processes such as insect outbreaks and wildfire. Despite this risk, existing projections of tree mortality are based on models that lack functionally realistic mortality mechanisms, and there has been no attempt to track observations of climate-driven tree mortality globally. Here we present the first global assessment of recent tree mortality attributed to drought and heat stress. Although episodic mortality occurs in the absence of climate change, studies compiled here suggest that at least some of the world's forested ecosystems already may be responding to climate change and raise concern that forests may become increasingly vulnerable to higher background tree mortality rates and die-off in response to future warming and drought, even in environments that are not normally considered water-limited. This further suggests risks to ecosystem services, including the loss of sequestered forest carbon and associated atmospheric feedbacks. Our review also identifies key information gaps and scientific uncertainties that currently hinder our ability to predict tree mortality in response to climate change and emphasizes the need for a globally coordinated observation system. Overall, our review reveals the potential for amplified tree mortality due to drought and heat in forests worldwide.  相似文献   

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