The nitrate-nitrogen（NO 3-N） concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using m...The nitrate-nitrogen（NO 3-N） concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and 2010.Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made.Results indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard：Quality Standard for Ground Water（≤ 20 mg/L）.Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems（4.1 ± 0.33 mg/L） than in forest ecosystems（0.5 ± 0.04 mg/L）.NO 3-N concentrations were relatively higher（〉 10 mg N /L） in 10 of the 43 wells sampled in the agricultural ecosystems.These elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are high.We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.展开更多
Background:Inputs of above-and belowground litter into forest soils are changing at an unprecedented rate due to continuing human disturbances and climate change.Microorganisms drive the soil carbon(C)cycle,but the ro...Background:Inputs of above-and belowground litter into forest soils are changing at an unprecedented rate due to continuing human disturbances and climate change.Microorganisms drive the soil carbon(C)cycle,but the roles of above-and belowground litter in regulating the soil microbial community have not been evaluated at a global scale.Methods:Here,we conducted a meta-analysis based on 68 aboveground litter removal and root exclusion studies across forest ecosystems to quantify the roles of above-and belowground litter on soil microbial community and compare their relative importance.Results:Aboveground litter removal significantly declined soil microbial biomass by 4.9%but root exclusion inhibited it stronger,up to 11.7%.Moreover,the aboveground litter removal significantly raised fungi by 10.1%without altering bacteria,leading to a 46.7%increase in the fungi-to-bacteria(F/B)ratio.Differently,root exclusion significantly decreased the fungi by 26.2%but increased the bacteria by 5.7%,causing a 13.3%decrease in the F/B ratio.Specifically,root exclusion significantly inhibited arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and actinomycetes by 22.9%,43.8%,and 7.9%,respectively.The negative effects of aboveground litter removal on microbial biomass increased with mean annual temperature and precipitation,whereas that of root exclusion on microbial biomass did not change with climatic factors but amplified with treatment duration.More importantly,greater effects of root exclusion on microbial biomass than aboveground litter removal were consistent across diverse forest biomes(expect boreal forests)and durations.Conclusions:These data provide a global evidence that root litter inputs exert a larger control on microbial biomass than aboveground litter inputs in forest ecosystems.Our study also highlights that changes in above-and belowground litter inputs could alter soil C stability differently by shifting the microbial community structure in the opposite direction.These findings are useful for predicting microbe-mediated C processes in response to changes in forest management or climate.展开更多
Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the ...Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades （1990-2011） in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of cli- mate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes （De Martonne and UNEP）. In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious （statistically significant） connection between thermal stress and the desiccation （degradation） of forest species in the analyzed area, with false acacia （Robinia Pseudoacacia） the main species to be impacted.展开更多
To build the artificial forest ecosystem is the major eco-economic development model in the watershed of Miyun Reservoir. It is very important to evaluate the benefits of those ecosystems. Emergy theories are very hel...To build the artificial forest ecosystem is the major eco-economic development model in the watershed of Miyun Reservoir. It is very important to evaluate the benefits of those ecosystems. Emergy theories are very helpful for us to establish a science-based assessment framework. Emergy evaluation of the artificial forest ecosystems in the watershed of Miyun Reservoir is used to asses the relative values of several ecological functions (sometimes called ecosystem services) and main ecosystem storages (sometimes called natural capital). The main driving energies, internal processes and storages are evaluated. The main functions, including transpiration, GPP and infiltration, are evaluated, which are 609em$/ha/yr, 6,245em$/ha/yr and 340em$/ha/yr respectively. The total values of major environmental services are 4,683em$/ha/yr in the artificial forest ecosystem. The main storages of natural capital including live biomass, soil moisture, organic matter, underground water and landform are estimated, which are 112,028em$/ha, 9em$/ha, 40,718em$/ha, 34em$/ha and 6,400,514em$/ha respectively. The largest value is landform, which accounts for 97.7% of these calculated total emdollar values. The concept of replacement value is explored using the emergy values of both ecosystem services and natural capital. The total calculated replacement values are 302,160em$/ha.展开更多
Background:Insect pests are a significant threat to natural resources and social development.Modeling species assemblages of insect pests can predict spatiotemporal pest dynamics.However,research gaps remain regarding...Background:Insect pests are a significant threat to natural resources and social development.Modeling species assemblages of insect pests can predict spatiotemporal pest dynamics.However,research gaps remain regarding the mechanism for determining species assemblages of insect pests in alpine forest ecosystems.Here,we explored these determinants using a field investigation conducted for insect pests in a region of the Qinghai-Tibet Plateau.We assessed the species assemblages of insect pests in alpine forest ecosystems based on species co-occurrence patterns and species diversity(i.e.,observed diversity,dark diversity,community completeness,and species pool).A probabilistic model was used to test for statistically significant pairwise patterns of species co-occurrence using the presence-absence matrix of pest species based on species interactions.We used ordinary least squares regression modeling to explore relationships between abiotic factors(i.e.,climate factors and human influence)and species diversity.Results:Positive pest species interactions and many association links can occur widely across different investigation sites and parts of plant hosts in alpine forest ecosystems.We detected high dark diversity and low community completeness of insect pests in alpine forest ecosystems.High temperature and precipitation could promote pest species diversity,particularly dark diversity and species pools.Human influence could drive high levels of pest species diversity and lead to dark diversity and species pools.Community completeness could be an effective indicator for insect pest risk assessment.Conclusions:Our study provides new evidence for the determinants of insect pest species assemblages in alpine forest ecosystems from the perspectives of pest species interactions and abiotic factors.The findings of our study could reveal the mechanism for shaping species assemblages and support the prevention and control of insect pests in alpine forest ecosystems.展开更多
Aims and ScopeForest Ecosystems is an international Open Access journal publishing scientific communications from any discipline that can provide interesting contributions about the structure and dynamics of ＂natural...Aims and ScopeForest Ecosystems is an international Open Access journal publishing scientific communications from any discipline that can provide interesting contributions about the structure and dynamics of ＂natural＂ and ＂domesticated＂ forest ecosystems, and their services to people. We welcome innovative science as well as application oriented work that will enhance understanding of woody plant communities. Very specific studies are welcome if they are part of a thematic series that provides some holistic perspective that is of general interest.展开更多
Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negat...Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service （IN-DI-ESS） driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis （TS-DEA） to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1） Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2） Spearman＇s rank correlation test was performed to compare the overall effectiveness in two periods： stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-D1-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.展开更多
A continuous three-year observation(from May 2008 to April 2011)was conducted to characterize the spatial variation of dissolved inorganic nitrogen(DIN)deposition at eight main forest ecosystems along the north-south ...A continuous three-year observation(from May 2008 to April 2011)was conducted to characterize the spatial variation of dissolved inorganic nitrogen(DIN)deposition at eight main forest ecosystems along the north-south transect of eastern China(NSTEC).The results show that both throughfall DIN deposition and bulk DIN deposition increase from north to south along the NSTEC.Throughfall DIN deposition varies greatly from 2.7 kg N/(ha·yr)to 33.0 kg N/(ha·yr),with an average of 10.6 kg N/(ha·yr),and bulk DIN deposition ranges from 4.1 kg N/(ha·yr)to 25.4 kg N/(ha·yr),with an average of 9.8 kg N/(ha·yr).NH4+-N is the dominant form of DIN deposition at most sampling sites.Additionally,the spatial variation of DIN deposition is controlled mainly by precipitation.Moreover,in the northern part of the NSTEC,bulk DIN deposition is 17%higher than throughfall DIN deposition,whereas the trend is opposite in the southern part of the NSTEC.The results demonstrate that DIN deposition would likely threaten the forest ecosystems along the NSTEC,compared with the critical loads(CL)of N deposition,and DIN deposition in this region is mostly controlled by agricultural activities rather than industrial activities or transportation.展开更多
Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the recipr...Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the reciprocal effects of C:N:P stoichiometry in plant–litter–soil systems. The present study analyzed C:N:P ratios in four age groups of Chinese pine, Pinus tabulaeformis Carr., forests in Shanxi Province, China: plantation young forests(AY,<20 year-old); plantation middle-aged forests(AM, 21–30 year-old); natural young forests(NY,<30 year-old); and natural middle-aged forests(NM,31–50 year-old). The average C:N:P ratios calculated for tree, shrub, and herbaceous leaves, litter, and soil(0–100 cm) were generally higher in NY followed by NM,AM, and AY. C:N and C:P ratios were higher in litter than in leaves and soils, and reached higher values in the litter and leaves of young forests than in middle-aged forests;however, C:N and C:P ratios were higher in soils of middle-aged forests than in young forests. N:P ratios were higher in leaves than in litter and soils regardless of stand age; the consistent N:P<14 values found in all forests indicated N limitations. With plant leaves, C:P ratios were highest in trees, followed by herbs and shrubs, indicating a higher efficiency in tree leaf formation. C:N ratios decreased with increasing soil depth, whereas there was no trend for C:P and N:P ratios. C:N:P stoichiometry of forest foliage did not exhibit a consistent variation according to stand age. Research on the relationships between N:P, and P, N nutrient limits and the characteristics of vegetation nutrient adaptation need to be continued.展开更多
This paper reviews the studies and research on climate change impacts on the forest ecosystems in Northeast China. The results show that in the context of global and regional warming, the growing season of coniferous ...This paper reviews the studies and research on climate change impacts on the forest ecosystems in Northeast China. The results show that in the context of global and regional warming, the growing season of coniferous forests has been increasing at an average rate of 3.9 d per decade. Regional warming favors the growth of temperate broad-leaved forests and has a detrimental effect on the growth of boreal coniferous forests. Over the past hundred years, the forest edge of the cool temperate zone in the southern Daxing＇anling region has retreated 140 km northward. From 1896 to 1986, the northern boundary of broad-leaved forests in Heilongjiang province has extended northwestward about 290 km. Future climatic changes （until 2060） may lead to the northern deciduous needle forests moving out of China＇s territory altogether. The occurrence cycles of pests and diseases have shortened; their distribution ranges have expanded. The life cycle of tent caterpillars （Malacosoma neustria testacea Motschulsky） has shortened from 14-15 years in the past to 8-10 years now. The pine caterpillar （Dendrolimus tabulaeformis Tsai et Liu）, which has spread within western Liaoning province and the nearby areas, can now be found in the north and west. Lightning fires in the Daxing＇anling region have significantly increased since 1987, and August has become the month when lightning fires occur most frequently. Overall, the net primary productivity （NPP） of forest in Northeast China has increased. The NPP in 1981 was around 0.27 Pg C, and increased to approximately 0.40 Pg C in 2002. With the current climate, the broad-leaved Korean pine forest ecosystem acts as a carbon sink, with a carbon sink capacity of 2.7 Mg C hm-2. Although the carbon sink capacity of the forest ecosystems in Northeast China has been weakened since 2003, the total carbon absorption will still increase. The forest ecosystems in Northeast China are likely to remain a significant carbon sink, and will play a positive role in the mitigation of climate change.展开更多
Forest soil carbon is a major carbon pool of terrestrial ecosystems,and accurate estimation of soil organic carbon(SOC)stocks in forest ecosystems is rather challenging.This study compared the prediction performance o...Forest soil carbon is a major carbon pool of terrestrial ecosystems,and accurate estimation of soil organic carbon(SOC)stocks in forest ecosystems is rather challenging.This study compared the prediction performance of three empirical model approaches namely,regression kriging(RK),multiple stepwise regression(MSR),random forest(RF),and boosted regression trees(BRT)to predict SOC stocks in Northeast China for 1990 and 2015.Furthermore,the spatial variation of SOC stocks and the main controlling environmental factors during the past 25 years were identified.A total of 82(in 1990)and 157(in 2015)topsoil(0–20 cm)samples with 12 environmental factors(soil property,climate,topography and biology)were selected for model construction.Randomly selected80%of the soil sample data were used to train the models and the other 20%data for model verification using mean absolute error,root mean square error,coefficient of determination and Lin's consistency correlation coefficient indices.We found BRT model as the best prediction model and it could explain 67%and 60%spatial variation of SOC stocks,in 1990,and 2015,respectively.Predicted maps of all models in both periods showed similar spatial distribution characteristics,with the lower SOC in northeast and higher SOC in southwest.Mean annual temperature and elevation were the key environmental factors influencing the spatial variation of SOC stock in both periods.SOC stocks were mainly stored under Cambosols,Gleyosols and Isohumosols,accounting for 95.6%(1990)and 95.9%(2015).Overall,SOC stocks increased by 471 Tg C during the past 25 years.Our study found that the BRT model employing common environmental factors was the most robust method for forest topsoil SOC stocks inventories.The spatial resolution of BRT model enabled us to pinpoint in which areas of Northeast China that new forest tree planting would be most effective for enhancing forest C stocks.Overall,our approach is likely to be useful in forestry management and ecological restoration at and beyond the regional scale.展开更多
To understand its source,distribution,storage,and translocation in the subtropical forest ecosystems,mercury(Hg)concentrations and stable isotopes in forest biomass tissues(foliage,branch,bark,and trunk)were investiga...To understand its source,distribution,storage,and translocation in the subtropical forest ecosystems,mercury(Hg)concentrations and stable isotopes in forest biomass tissues(foliage,branch,bark,and trunk)were investigated at Ailao Mountain National Nature Reserve,Southwest China.The total Hg(THg)concentrations in the samples show the following trend:mature foliage(57±19 ng g-1)>bark(11±4.0 ng g-1)>branch(5.4±2.5 ng g-1)>trunk(1.6±0.7 ng g-1).Using the measured THg concentrations and the quantity of respective biomasses,the Hg pools in the forest are:wood(60±26μg m-2)>bark(51±18μg m-2)>foliage(41±11μg m-2)>branch(26±8.3μg m-2).The tree biomasses displayed negativeδ202Hg(-1.83‰to-3.84‰)andΔ199Hg(-0.18‰to-0.62‰).The observedΔ200Hg(-0.08‰to 0.04‰)is not significantly from zero.AΔ199Hg/Δ201Hg ratio of 1.05 was found in tree biomasses,suggesting that mercury has undergone Hg(Ⅱ)photoreduction processes.A Hg-isotope based binary mixing model suggests that Hg in the tree biomasses mainly originated from foliage uptake of atmospheric Hg0,constituting 67%,80%,and 77%of Hg in wood,branch,and bark,respectively.Our study sheds new light on the transportation and sources of Hg in the subtropical forest ecosystems.展开更多
From the biological point of view the value of autotrophy plant association is determined by the carbon fixation and the carbon cycle. Among the plant associations of Hungary, forest has the largest biological carbon ...From the biological point of view the value of autotrophy plant association is determined by the carbon fixation and the carbon cycle. Among the plant associations of Hungary, forest has the largest biological carbon fixation and carbon cycle. In general, the annual water cycle is the key factor in the organic material production of the Hungarian forests. The most intensive water con- sumption and organic material production take place from May till July, which period is named main water consumption and respec- tively main growing period, In Hungary the categories of the forest climate are characterized by main tree species and based on the characteristic meteorological data （Jaro and Tatraaljai, 1985）. In Hungary the forest area covered by stand is 1,650,000 hm2. Beech forest climate covers 8% of the forest area, hornbeam-oak forest climate covers 22%, sessile oak-Turkey oak forest climate covers 48% and forest steppe climate covers 22%. Partly in the frame of ICP-Forests, the Department of Ecology in the Forest Research Institute carries out long term, complex ecophysiological investigations on several sample plots （so-called basic plots） throughout the whole country. The organic material production （growth）, the nutrient and water cycle, the measurements of air pollutants and mete- orological parameters, as well as chemical analyses are all part of the investigations. As a comparison the figure of two basic plots （Sopron Pasp0kladfiny） shows the water cycles of a good growing beech stand in beech climate and a wcak pedunculate oak stand in forest steppe climate in the hydrological year of 2001-2002. In the Hungarian forest 60% 70% of the precipitation is used for inter- ception, evaporation, and in the vegetation season, for the transpiration both in beech and forest steppe climate. From other point of view, only 30%-40% of the open air precipitation infiltrates into the soil and can be utilized by the forest.展开更多
Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to im...Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion, we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme “Prevention is priority, but integrated with curative techniques and ecological resilience” on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosys-tems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.展开更多
Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a surve...Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a survey of current biomass estimation methods using remote sensing data and discusses four critical issues–collection of field-based biomass reference data,extraction and selection of suitable variables from remote sensing data,identification of proper algorithms to develop biomass estimation models,and uncertainty analysis to refine the estimation procedure.Additionally,we discuss the impacts of scales on biomass estimation performance and describe a general biomass estimation procedure.Although optical sensor and radar data have been primary sources for AGB estimation,data saturation is an important factor resulting in estimation uncertainty.LIght Detection and Ranging(lidar)can remove data saturation,but limited availability of lidar data prevents its extensive application.This literature survey has indicated the limitations of using single-sensor data for biomass estimation and the importance of integrating multi-sensor/scale remote sensing data to produce accurate estimates over large areas.More research is needed to extract a vertical vegetation structure(e.g.canopy height)from interferometry synthetic aperture radar(InSAR)or optical stereo images to incorporate it into horizontal structures(e.g.canopy cover)in biomass estimation modeling.展开更多
Numerous clustering algorithms are valuable in pattern recognition in forest vegetation,with new ones continually being proposed.While some are well-known,others are underutilized in vegetation science.This study comp...Numerous clustering algorithms are valuable in pattern recognition in forest vegetation,with new ones continually being proposed.While some are well-known,others are underutilized in vegetation science.This study compares the performance of practical iterative reallocation algorithms with model-based clustering algorithms.The data is from forest vegetation in Virginia(United States),the Hyrcanian Forest(Asia),and European beech forests.Practical iterative reallocation algorithms were applied as non-hierarchical methods and Finite Gaussian mixture modeling was used as a model-based clustering method.Due to limitations on dimensionality in model-based clustering,principal coordinates analysis was employed to reduce the dataset’s dimensions.A log transformation was applied to achieve a normal distribution for the pseudo-species data before calculating the Bray-Curtis dissimilarity.The findings indicate that the reallocation of misclassified objects based on silhouette width(OPTSIL)with Flexible-β(-0.25)had the highest mean among the tested clustering algorithms with Silhouette width 1(REMOS1)with Flexible-β(-0.25)second.However,model-based clustering performed poorly.Based on these results,it is recommended using OPTSIL with Flexible-β(-0.25)and REMOS1 with Flexible-β(-0.25)for forest vegetation classification instead of model-based clustering particularly for heterogeneous datasets common in forest vegetation community data.展开更多
Forest ecosystems are among the most important and play a vital role in maintaining ecological balance and supporting biodiversity.Integrated forest management(IFM)has gained prominence in European countries as a stra...Forest ecosystems are among the most important and play a vital role in maintaining ecological balance and supporting biodiversity.Integrated forest management(IFM)has gained prominence in European countries as a strategy to meet human needs for ecosystem services while ensuring biodiversity conservation.Given the complementary strengths of China and the European Union(EU)in forestry and the potential for collaboration,it is beneficial to compare and analyze the research status of both in IFMrelated fields to provide insights into key areas and future directions for cooperation.This study employs bibliometric analysis to systematically evaluate IFM-related research status and trends between China and the EU.By examining publication trends,collaborative networks,prominent scholars,keyword co-occurrence patterns,research hotspots,and thematic clusters,providing a comprehensive overview of IFM-related research.The findings reveal that core research areas—such as forest management practices,ecosystem services,biodiversity conservation,and data-driven assessment methods—remain central to IFM-related research.In contrast,frontiers in climate change mitigation,disturbance and restoration dynamics,and multi-stakeholder governance represent critical areas for future exploration and collaboration.Our results provide areas for enhancing China-EU collaboration in future research in IFM.展开更多
Forest ecosystems play key roles in mitigating human-induced climate change through enhanced carbon uptake;however,frequently occurring climate extremes and human activities have considerably threatened the stability ...Forest ecosystems play key roles in mitigating human-induced climate change through enhanced carbon uptake;however,frequently occurring climate extremes and human activities have considerably threatened the stability of forests.At the same time,detailed accounts of disturbances and forest responses are not yet well quantified in Asia.This study employed the Breaks For Additive Seasonal and Trend method-an abrupt-change detection method-to analyze the Enhanced Vegetation Index time series in East Asia,South Asia,and Southeast Asia.This approach allowed us to detect forest disturbance and quantify the resilience after disturbance.Results showed that 20%of forests experienced disturbance with an increasing trend from 2000 to 2022,and Southeast Asian countries were more severely affected by disturbances.Specifically,95%of forests had robust resilience and could recover from disturbance within a few decades.The resilience of forests suffering from greater magnitude of disturbance tended to be stronger than forests with lower disturbance magnitude.In summary,this study investigated the resilience of forests across the low and middle latitudes of Asia over the past two decades.The authors found that most forests exhibited good resilience after disturbance and about two-thirds had recovered to a better state in 2022.The findings of this study underscore the complex relationship between disturbance and resilience,contributing to comprehension of forest resilience through satellite remote sensing.展开更多
Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-cano...Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.展开更多
Pueraria montana is a perennial twining vine species of Pueraria in Leguminosae.Because of its fast growth and strong climbing and covering ability,this species has the potential threat of invading forest ecosystem.Ba...Pueraria montana is a perennial twining vine species of Pueraria in Leguminosae.Because of its fast growth and strong climbing and covering ability,this species has the potential threat of invading forest ecosystem.Based on the investigation of the occurrence and harm of P.montana in the"four mountains"forest ecosystem in the central urban area of Chongqing,combined with its growth habits and biological characteristics,we comprehensively evaluated its harm risk.The results show that P.montana is widely distributed in the forest ecosystem within the"four mountains"in the central urban area of Chongqing.On average,there was a distribution site of P.montana every 1.38 km of forest road with a scale of 0.43 hm 2/survey point and a coverage of about 42.86%.P.montana mainly occupy forest land by covering and climbing,threatening the original vegetation of forest land.It grows rapidly,and its ability of diffusion and colonization is very strong.The average length of new branches was 11.52 m/year,and the number of effective tillers was 5.25.According to National Forestry Pest Risk Analysis Index System,the risk assessment value of P.montana was 2.51,so it is a medium-risk harmful plant to forestry.It is suggested that the forestry department should strengthen the management of P.montana to prevent its further spread.展开更多
基金supported by the Key Direction in Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-EW-310)the National Natural Science Foundation of China (No. 41171153)
文摘The nitrate-nitrogen（NO 3-N） concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations,representing typical agroand forest ecosystems,were assessed using monitoring data collected between 2004 and 2010.Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater,and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made.Results indicated that most of the NO 3--N concentrations in groundwater from the agroand forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard：Quality Standard for Ground Water（≤ 20 mg/L）.Over the study period,the average NO 3--N concentrations were significantly higher in agro-ecosystems（4.1 ± 0.33 mg/L） than in forest ecosystems（0.5 ± 0.04 mg/L）.NO 3-N concentrations were relatively higher（〉 10 mg N /L） in 10 of the 43 wells sampled in the agricultural ecosystems.These elevated concentrations occurred mainly in the Ansai,Yucheng,Linze,Fukang,Akesu,and Cele field sites,which were located in arid and semiarid areas where irrigation rates are high.We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.
基金supported by the National Natural Science Foundation of China(31830015,31901302).
文摘Background:Inputs of above-and belowground litter into forest soils are changing at an unprecedented rate due to continuing human disturbances and climate change.Microorganisms drive the soil carbon(C)cycle,but the roles of above-and belowground litter in regulating the soil microbial community have not been evaluated at a global scale.Methods:Here,we conducted a meta-analysis based on 68 aboveground litter removal and root exclusion studies across forest ecosystems to quantify the roles of above-and belowground litter on soil microbial community and compare their relative importance.Results:Aboveground litter removal significantly declined soil microbial biomass by 4.9%but root exclusion inhibited it stronger,up to 11.7%.Moreover,the aboveground litter removal significantly raised fungi by 10.1%without altering bacteria,leading to a 46.7%increase in the fungi-to-bacteria(F/B)ratio.Differently,root exclusion significantly decreased the fungi by 26.2%but increased the bacteria by 5.7%,causing a 13.3%decrease in the F/B ratio.Specifically,root exclusion significantly inhibited arbuscular mycorrhizal fungi,ectomycorrhizal fungi,and actinomycetes by 22.9%,43.8%,and 7.9%,respectively.The negative effects of aboveground litter removal on microbial biomass increased with mean annual temperature and precipitation,whereas that of root exclusion on microbial biomass did not change with climatic factors but amplified with treatment duration.More importantly,greater effects of root exclusion on microbial biomass than aboveground litter removal were consistent across diverse forest biomes(expect boreal forests)and durations.Conclusions:These data provide a global evidence that root litter inputs exert a larger control on microbial biomass than aboveground litter inputs in forest ecosystems.Our study also highlights that changes in above-and belowground litter inputs could alter soil C stability differently by shifting the microbial community structure in the opposite direction.These findings are useful for predicting microbe-mediated C processes in response to changes in forest management or climate.
基金supported by the project Territorial Management Based on Growth Poles Theory (UEFICSU-PNII-Idei, 1950)the contract POSDRU/86/1.2/S/57462, strategic project "Optimization of the insertion process on the labour market concerning the geography graduates", co-financed by the European Social Fund, through the Sectoral Operational Programme for the Human Resources Development 2007–2013
文摘Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades （1990-2011） in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of cli- mate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes （De Martonne and UNEP）. In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious （statistically significant） connection between thermal stress and the desiccation （degradation） of forest species in the analyzed area, with false acacia （Robinia Pseudoacacia） the main species to be impacted.
文摘To build the artificial forest ecosystem is the major eco-economic development model in the watershed of Miyun Reservoir. It is very important to evaluate the benefits of those ecosystems. Emergy theories are very helpful for us to establish a science-based assessment framework. Emergy evaluation of the artificial forest ecosystems in the watershed of Miyun Reservoir is used to asses the relative values of several ecological functions (sometimes called ecosystem services) and main ecosystem storages (sometimes called natural capital). The main driving energies, internal processes and storages are evaluated. The main functions, including transpiration, GPP and infiltration, are evaluated, which are 609em$/ha/yr, 6,245em$/ha/yr and 340em$/ha/yr respectively. The total values of major environmental services are 4,683em$/ha/yr in the artificial forest ecosystem. The main storages of natural capital including live biomass, soil moisture, organic matter, underground water and landform are estimated, which are 112,028em$/ha, 9em$/ha, 40,718em$/ha, 34em$/ha and 6,400,514em$/ha respectively. The largest value is landform, which accounts for 97.7% of these calculated total emdollar values. The concept of replacement value is explored using the emergy values of both ecosystem services and natural capital. The total calculated replacement values are 302,160em$/ha.
基金supported by the National Natural Science Foundation of China(Nos.31800449 and 31800464)the project of the third forestry pest survey of Qinghai Province,China.
文摘Background:Insect pests are a significant threat to natural resources and social development.Modeling species assemblages of insect pests can predict spatiotemporal pest dynamics.However,research gaps remain regarding the mechanism for determining species assemblages of insect pests in alpine forest ecosystems.Here,we explored these determinants using a field investigation conducted for insect pests in a region of the Qinghai-Tibet Plateau.We assessed the species assemblages of insect pests in alpine forest ecosystems based on species co-occurrence patterns and species diversity(i.e.,observed diversity,dark diversity,community completeness,and species pool).A probabilistic model was used to test for statistically significant pairwise patterns of species co-occurrence using the presence-absence matrix of pest species based on species interactions.We used ordinary least squares regression modeling to explore relationships between abiotic factors(i.e.,climate factors and human influence)and species diversity.Results:Positive pest species interactions and many association links can occur widely across different investigation sites and parts of plant hosts in alpine forest ecosystems.We detected high dark diversity and low community completeness of insect pests in alpine forest ecosystems.High temperature and precipitation could promote pest species diversity,particularly dark diversity and species pools.Human influence could drive high levels of pest species diversity and lead to dark diversity and species pools.Community completeness could be an effective indicator for insect pest risk assessment.Conclusions:Our study provides new evidence for the determinants of insect pest species assemblages in alpine forest ecosystems from the perspectives of pest species interactions and abiotic factors.The findings of our study could reveal the mechanism for shaping species assemblages and support the prevention and control of insect pests in alpine forest ecosystems.
文摘Aims and ScopeForest Ecosystems is an international Open Access journal publishing scientific communications from any discipline that can provide interesting contributions about the structure and dynamics of ＂natural＂ and ＂domesticated＂ forest ecosystems, and their services to people. We welcome innovative science as well as application oriented work that will enhance understanding of woody plant communities. Very specific studies are welcome if they are part of a thematic series that provides some holistic perspective that is of general interest.
基金Under the auspices of Science and Technology Service Network Initiative Project of the Chinese Academy of Sciences(No.KFJ-EW-STS-002)
文摘Identifying the driving forces that cause changes in forest ecosystem services related to water conservation is essential for the design of interventions that could enhance positive impacts as well as minimizing negative impacts. In this study, we propose an assessment concept framework model for indirect-direct-ecosystem service （IN-DI-ESS） driving forces within this context and method for index construction that considers the selection of a robust and parsimonious variable set. Factor analysis was integrated into two-stage data envelopment analysis （TS-DEA） to determine the driving forces and their effects on water conservation services in forest ecosystems at the provincial scale in China. The results showed the following. 1） Ten indicators with factor scores more than 0.8 were selected as the minimum data set. Four indicators comprising population density, per capita gross domestic product, irrigation efficiency, and per capita food consumption were the indirect driving factors, and six indicators comprising precipitation, farmland into forestry or pasture, forest cover, habitat area, water footprint, and wood extraction were the direct driving forces. 2） Spearman＇s rank correlation test was performed to compare the overall effectiveness in two periods： stage 1 and stage 2. The calculated coefficients were 0.245, 0.136, and 0.579, respectively, whereas the tabulated value was 0.562. This indicates that the driving forces obviously differed in terms of their contribution to the overall effectiveness and they caused changes in water conservation services in different stages. In terms of the variations in different driving force effects in the years 2000 and 2010, the overall, stage 1, and stage 2 variances were 0.020, 0.065, and 0.079 in 2000, respectively, and 0.018, 0.063, and 0.071 in 2010. This also indicates that heterogeneous driving force effects were obvious in the process during the same period. Identifying the driving forces that affect service changes and evaluating their efficiency have significant policy implications for the management of forest ecosystem services. Advanced effectiveness measures for weak regions could be improved in an appropriate manner. In this study, we showed that factor analysis coupled with TS-DEA based on the IN-D1-ESS framework can increase the parsimony of driving force indicators, as well as interpreting the interactions among indirect and direct driving forces with forest ecosystem water conservation services, and reducing the uncertainty related to the internal consistency during data selection.
基金Under the auspices of Major State Basic Research Development Program of China(No.2010CB833504)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05050601)
文摘A continuous three-year observation(from May 2008 to April 2011)was conducted to characterize the spatial variation of dissolved inorganic nitrogen(DIN)deposition at eight main forest ecosystems along the north-south transect of eastern China(NSTEC).The results show that both throughfall DIN deposition and bulk DIN deposition increase from north to south along the NSTEC.Throughfall DIN deposition varies greatly from 2.7 kg N/(ha·yr)to 33.0 kg N/(ha·yr),with an average of 10.6 kg N/(ha·yr),and bulk DIN deposition ranges from 4.1 kg N/(ha·yr)to 25.4 kg N/(ha·yr),with an average of 9.8 kg N/(ha·yr).NH4+-N is the dominant form of DIN deposition at most sampling sites.Additionally,the spatial variation of DIN deposition is controlled mainly by precipitation.Moreover,in the northern part of the NSTEC,bulk DIN deposition is 17%higher than throughfall DIN deposition,whereas the trend is opposite in the southern part of the NSTEC.The results demonstrate that DIN deposition would likely threaten the forest ecosystems along the NSTEC,compared with the critical loads(CL)of N deposition,and DIN deposition in this region is mostly controlled by agricultural activities rather than industrial activities or transportation.
基金supported by the ‘‘Doctoral Scientific Research Foundation’’ of Heilongjiang Bayi Agricultural University,Grant No.XDB2015-02 and the ‘‘Strategic Priority Research Program’’ of the Chinese Academy of Sciences,Grant No.XDA05050203-04-01
文摘Although carbon(C), nitrogen(N), and phosphorous(P) stoichiometric ratios are considered good indicators of nutrient excess/limitation and thus of ecosystem health, few reports have discussed the trends and the reciprocal effects of C:N:P stoichiometry in plant–litter–soil systems. The present study analyzed C:N:P ratios in four age groups of Chinese pine, Pinus tabulaeformis Carr., forests in Shanxi Province, China: plantation young forests(AY,<20 year-old); plantation middle-aged forests(AM, 21–30 year-old); natural young forests(NY,<30 year-old); and natural middle-aged forests(NM,31–50 year-old). The average C:N:P ratios calculated for tree, shrub, and herbaceous leaves, litter, and soil(0–100 cm) were generally higher in NY followed by NM,AM, and AY. C:N and C:P ratios were higher in litter than in leaves and soils, and reached higher values in the litter and leaves of young forests than in middle-aged forests;however, C:N and C:P ratios were higher in soils of middle-aged forests than in young forests. N:P ratios were higher in leaves than in litter and soils regardless of stand age; the consistent N:P<14 values found in all forests indicated N limitations. With plant leaves, C:P ratios were highest in trees, followed by herbs and shrubs, indicating a higher efficiency in tree leaf formation. C:N ratios decreased with increasing soil depth, whereas there was no trend for C:P and N:P ratios. C:N:P stoichiometry of forest foliage did not exhibit a consistent variation according to stand age. Research on the relationships between N:P, and P, N nutrient limits and the characteristics of vegetation nutrient adaptation need to be continued.
基金the Public Research Institute Fun-damental Research Foundation of the Institute of Atmospheric Environment of ChinaChina Meteororlgical Administration(No.2011IAE-CMA01)+1 种基金National Natural Science Foundation of China(No.41171199)the Special Climate Change Research Program Foundation of China Meteororlgical Administration(No.062700s010c01)for providing supports
文摘This paper reviews the studies and research on climate change impacts on the forest ecosystems in Northeast China. The results show that in the context of global and regional warming, the growing season of coniferous forests has been increasing at an average rate of 3.9 d per decade. Regional warming favors the growth of temperate broad-leaved forests and has a detrimental effect on the growth of boreal coniferous forests. Over the past hundred years, the forest edge of the cool temperate zone in the southern Daxing＇anling region has retreated 140 km northward. From 1896 to 1986, the northern boundary of broad-leaved forests in Heilongjiang province has extended northwestward about 290 km. Future climatic changes （until 2060） may lead to the northern deciduous needle forests moving out of China＇s territory altogether. The occurrence cycles of pests and diseases have shortened; their distribution ranges have expanded. The life cycle of tent caterpillars （Malacosoma neustria testacea Motschulsky） has shortened from 14-15 years in the past to 8-10 years now. The pine caterpillar （Dendrolimus tabulaeformis Tsai et Liu）, which has spread within western Liaoning province and the nearby areas, can now be found in the north and west. Lightning fires in the Daxing＇anling region have significantly increased since 1987, and August has become the month when lightning fires occur most frequently. Overall, the net primary productivity （NPP） of forest in Northeast China has increased. The NPP in 1981 was around 0.27 Pg C, and increased to approximately 0.40 Pg C in 2002. With the current climate, the broad-leaved Korean pine forest ecosystem acts as a carbon sink, with a carbon sink capacity of 2.7 Mg C hm-2. Although the carbon sink capacity of the forest ecosystems in Northeast China has been weakened since 2003, the total carbon absorption will still increase. The forest ecosystems in Northeast China are likely to remain a significant carbon sink, and will play a positive role in the mitigation of climate change.
基金funded by the National Key R&D Program of China(Grant No.2021YFD1500200)National Natural Science Foundation of China(Grant No.42077149)+4 种基金China Postdoctoral Science Foundation(Grant No.2019M660782)National Science and Technology Basic Resources Survey Program of China(Grant No.2019FY101300)Doctoral research start-up fund project of Liaoning Provincial Department of Science and Technology(Grant No.2021-BS-136)China Scholarship Council(201908210132)Young Scientific and Technological Talents Project of Liaoning Province(Grant Nos.LSNQN201910 and LSNQN201914)。
文摘Forest soil carbon is a major carbon pool of terrestrial ecosystems,and accurate estimation of soil organic carbon(SOC)stocks in forest ecosystems is rather challenging.This study compared the prediction performance of three empirical model approaches namely,regression kriging(RK),multiple stepwise regression(MSR),random forest(RF),and boosted regression trees(BRT)to predict SOC stocks in Northeast China for 1990 and 2015.Furthermore,the spatial variation of SOC stocks and the main controlling environmental factors during the past 25 years were identified.A total of 82(in 1990)and 157(in 2015)topsoil(0–20 cm)samples with 12 environmental factors(soil property,climate,topography and biology)were selected for model construction.Randomly selected80%of the soil sample data were used to train the models and the other 20%data for model verification using mean absolute error,root mean square error,coefficient of determination and Lin's consistency correlation coefficient indices.We found BRT model as the best prediction model and it could explain 67%and 60%spatial variation of SOC stocks,in 1990,and 2015,respectively.Predicted maps of all models in both periods showed similar spatial distribution characteristics,with the lower SOC in northeast and higher SOC in southwest.Mean annual temperature and elevation were the key environmental factors influencing the spatial variation of SOC stock in both periods.SOC stocks were mainly stored under Cambosols,Gleyosols and Isohumosols,accounting for 95.6%(1990)and 95.9%(2015).Overall,SOC stocks increased by 471 Tg C during the past 25 years.Our study found that the BRT model employing common environmental factors was the most robust method for forest topsoil SOC stocks inventories.The spatial resolution of BRT model enabled us to pinpoint in which areas of Northeast China that new forest tree planting would be most effective for enhancing forest C stocks.Overall,our approach is likely to be useful in forestry management and ecological restoration at and beyond the regional scale.
基金funded by the National Natural Science Foundation of China(No.41430754)。
文摘To understand its source,distribution,storage,and translocation in the subtropical forest ecosystems,mercury(Hg)concentrations and stable isotopes in forest biomass tissues(foliage,branch,bark,and trunk)were investigated at Ailao Mountain National Nature Reserve,Southwest China.The total Hg(THg)concentrations in the samples show the following trend:mature foliage(57±19 ng g-1)>bark(11±4.0 ng g-1)>branch(5.4±2.5 ng g-1)>trunk(1.6±0.7 ng g-1).Using the measured THg concentrations and the quantity of respective biomasses,the Hg pools in the forest are:wood(60±26μg m-2)>bark(51±18μg m-2)>foliage(41±11μg m-2)>branch(26±8.3μg m-2).The tree biomasses displayed negativeδ202Hg(-1.83‰to-3.84‰)andΔ199Hg(-0.18‰to-0.62‰).The observedΔ200Hg(-0.08‰to 0.04‰)is not significantly from zero.AΔ199Hg/Δ201Hg ratio of 1.05 was found in tree biomasses,suggesting that mercury has undergone Hg(Ⅱ)photoreduction processes.A Hg-isotope based binary mixing model suggests that Hg in the tree biomasses mainly originated from foliage uptake of atmospheric Hg0,constituting 67%,80%,and 77%of Hg in wood,branch,and bark,respectively.Our study sheds new light on the transportation and sources of Hg in the subtropical forest ecosystems.
文摘From the biological point of view the value of autotrophy plant association is determined by the carbon fixation and the carbon cycle. Among the plant associations of Hungary, forest has the largest biological carbon fixation and carbon cycle. In general, the annual water cycle is the key factor in the organic material production of the Hungarian forests. The most intensive water con- sumption and organic material production take place from May till July, which period is named main water consumption and respec- tively main growing period, In Hungary the categories of the forest climate are characterized by main tree species and based on the characteristic meteorological data （Jaro and Tatraaljai, 1985）. In Hungary the forest area covered by stand is 1,650,000 hm2. Beech forest climate covers 8% of the forest area, hornbeam-oak forest climate covers 22%, sessile oak-Turkey oak forest climate covers 48% and forest steppe climate covers 22%. Partly in the frame of ICP-Forests, the Department of Ecology in the Forest Research Institute carries out long term, complex ecophysiological investigations on several sample plots （so-called basic plots） throughout the whole country. The organic material production （growth）, the nutrient and water cycle, the measurements of air pollutants and mete- orological parameters, as well as chemical analyses are all part of the investigations. As a comparison the figure of two basic plots （Sopron Pasp0kladfiny） shows the water cycles of a good growing beech stand in beech climate and a wcak pedunculate oak stand in forest steppe climate in the hydrological year of 2001-2002. In the Hungarian forest 60% 70% of the precipitation is used for inter- ception, evaporation, and in the vegetation season, for the transpiration both in beech and forest steppe climate. From other point of view, only 30%-40% of the open air precipitation infiltrates into the soil and can be utilized by the forest.
文摘Pine wood nematode （PWN）, Bursaphelenchus xylophilus （Steiner et Buhrer） Nickle is an important invasive alien species in forests of China and has become one of the most destructive forest diseases. In order to improve the resistance and resilience of pine forest ecosystems against B. xylophilus invasion and make the pine forest ecosystem more timely responsive to PWN invasion, we made some recommendations based on five years of intensive observations. We advocate a set of management measures with the theme “Prevention is priority, but integrated with curative techniques and ecological resilience” on the pine forest ecosystem invaded by B. xylophilus; details of accurate measures are proposed. The aim is to discover the underlying problems of present pine forest ecosys-tems and to take, correspondingly, administrative measures and strategies, which will encourage the pine forest ecosystem to develop in a benign way.
基金a grant from Research Center of Agricultural and Forestry Carbon Sinks and Ecological Environmental Remediation,Zhejiang A&F University.
文摘Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a survey of current biomass estimation methods using remote sensing data and discusses four critical issues–collection of field-based biomass reference data,extraction and selection of suitable variables from remote sensing data,identification of proper algorithms to develop biomass estimation models,and uncertainty analysis to refine the estimation procedure.Additionally,we discuss the impacts of scales on biomass estimation performance and describe a general biomass estimation procedure.Although optical sensor and radar data have been primary sources for AGB estimation,data saturation is an important factor resulting in estimation uncertainty.LIght Detection and Ranging(lidar)can remove data saturation,but limited availability of lidar data prevents its extensive application.This literature survey has indicated the limitations of using single-sensor data for biomass estimation and the importance of integrating multi-sensor/scale remote sensing data to produce accurate estimates over large areas.More research is needed to extract a vertical vegetation structure(e.g.canopy height)from interferometry synthetic aperture radar(InSAR)or optical stereo images to incorporate it into horizontal structures(e.g.canopy cover)in biomass estimation modeling.
基金financially supported by the vice chancellor for research and technology of Urmia University
文摘Numerous clustering algorithms are valuable in pattern recognition in forest vegetation,with new ones continually being proposed.While some are well-known,others are underutilized in vegetation science.This study compares the performance of practical iterative reallocation algorithms with model-based clustering algorithms.The data is from forest vegetation in Virginia(United States),the Hyrcanian Forest(Asia),and European beech forests.Practical iterative reallocation algorithms were applied as non-hierarchical methods and Finite Gaussian mixture modeling was used as a model-based clustering method.Due to limitations on dimensionality in model-based clustering,principal coordinates analysis was employed to reduce the dataset’s dimensions.A log transformation was applied to achieve a normal distribution for the pseudo-species data before calculating the Bray-Curtis dissimilarity.The findings indicate that the reallocation of misclassified objects based on silhouette width(OPTSIL)with Flexible-β(-0.25)had the highest mean among the tested clustering algorithms with Silhouette width 1(REMOS1)with Flexible-β(-0.25)second.However,model-based clustering performed poorly.Based on these results,it is recommended using OPTSIL with Flexible-β(-0.25)and REMOS1 with Flexible-β(-0.25)for forest vegetation classification instead of model-based clustering particularly for heterogeneous datasets common in forest vegetation community data.
基金was supported by the National Key R&D Program of China(grant number:2023YFE0112804)。
文摘Forest ecosystems are among the most important and play a vital role in maintaining ecological balance and supporting biodiversity.Integrated forest management(IFM)has gained prominence in European countries as a strategy to meet human needs for ecosystem services while ensuring biodiversity conservation.Given the complementary strengths of China and the European Union(EU)in forestry and the potential for collaboration,it is beneficial to compare and analyze the research status of both in IFMrelated fields to provide insights into key areas and future directions for cooperation.This study employs bibliometric analysis to systematically evaluate IFM-related research status and trends between China and the EU.By examining publication trends,collaborative networks,prominent scholars,keyword co-occurrence patterns,research hotspots,and thematic clusters,providing a comprehensive overview of IFM-related research.The findings reveal that core research areas—such as forest management practices,ecosystem services,biodiversity conservation,and data-driven assessment methods—remain central to IFM-related research.In contrast,frontiers in climate change mitigation,disturbance and restoration dynamics,and multi-stakeholder governance represent critical areas for future exploration and collaboration.Our results provide areas for enhancing China-EU collaboration in future research in IFM.
基金jointly supported by the National Natural Science Foundation of China [grant number 42265012]the Funding by the Fengyun Application Pioneering Project [grant number FY-APP-ZX-2022.0221]。
文摘Forest ecosystems play key roles in mitigating human-induced climate change through enhanced carbon uptake;however,frequently occurring climate extremes and human activities have considerably threatened the stability of forests.At the same time,detailed accounts of disturbances and forest responses are not yet well quantified in Asia.This study employed the Breaks For Additive Seasonal and Trend method-an abrupt-change detection method-to analyze the Enhanced Vegetation Index time series in East Asia,South Asia,and Southeast Asia.This approach allowed us to detect forest disturbance and quantify the resilience after disturbance.Results showed that 20%of forests experienced disturbance with an increasing trend from 2000 to 2022,and Southeast Asian countries were more severely affected by disturbances.Specifically,95%of forests had robust resilience and could recover from disturbance within a few decades.The resilience of forests suffering from greater magnitude of disturbance tended to be stronger than forests with lower disturbance magnitude.In summary,this study investigated the resilience of forests across the low and middle latitudes of Asia over the past two decades.The authors found that most forests exhibited good resilience after disturbance and about two-thirds had recovered to a better state in 2022.The findings of this study underscore the complex relationship between disturbance and resilience,contributing to comprehension of forest resilience through satellite remote sensing.
基金supported by the MITACS Accelerate grant with Greenfirst,industry partner in La Sarre,QC,Canada.
文摘Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.
基金Supported by Special Project of Performance Incentive and Guidance for Scientific Research Institutions in Chongqing(cstc2022jxjl80025).
文摘Pueraria montana is a perennial twining vine species of Pueraria in Leguminosae.Because of its fast growth and strong climbing and covering ability,this species has the potential threat of invading forest ecosystem.Based on the investigation of the occurrence and harm of P.montana in the"four mountains"forest ecosystem in the central urban area of Chongqing,combined with its growth habits and biological characteristics,we comprehensively evaluated its harm risk.The results show that P.montana is widely distributed in the forest ecosystem within the"four mountains"in the central urban area of Chongqing.On average,there was a distribution site of P.montana every 1.38 km of forest road with a scale of 0.43 hm 2/survey point and a coverage of about 42.86%.P.montana mainly occupy forest land by covering and climbing,threatening the original vegetation of forest land.It grows rapidly,and its ability of diffusion and colonization is very strong.The average length of new branches was 11.52 m/year,and the number of effective tillers was 5.25.According to National Forestry Pest Risk Analysis Index System,the risk assessment value of P.montana was 2.51,so it is a medium-risk harmful plant to forestry.It is suggested that the forestry department should strengthen the management of P.montana to prevent its further spread.
