Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological metho...Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central Bhutan.Analysis of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over time.One site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 years.At both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance regime.The hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release events.From 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer recruitment.Over the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these stands.Significant variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development patterns.This study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central Bhutan.It also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management in the future.展开更多
Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC c...Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution even-ness.Our results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural forests.How-ever,SOC chemical compositions were appreciably more evenly distributed in plantations.Based on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under disturbances.In tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to decomposition.Climate factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical forests.This could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.展开更多
Examining the contribution of hemispherical photographs in the understanding of Natural forest regeneration is very important in estimating the future forest structure, composition and to enforce conservation regulati...Examining the contribution of hemispherical photographs in the understanding of Natural forest regeneration is very important in estimating the future forest structure, composition and to enforce conservation regulations. This study sets out to examine the interaction between stump sprouting, LAI, site and canopy openness for the entire AKAK forest area and for the logging compartments;2013, 2015 and 2017 respectively. 49 sprouted stump were identified randonly. 20 m × 20 m plots were demarcated along a canopy gaps for each sprouted stump, the plots were established in such a manner that the sprouted stumps will be in the middle. For each of the selected 49 sprouted stump, indirect measurements of canopy cover were performed in the 49 plots of 20 m × 20 m (0.04 ha), giving a total of 1.96 ha of land covered. Galaxy S3 smartphone with a built-in Infinix ZERO 4 fish-eye lens with 198˚ view angle equidistant projection was used to take photos. The fish-eye lens was mounted on the phone camera and photograph were taken at a fixed height of 1.3 m. Results revealed that, the combine Principal Component Factor Analysis (2013, 2015 and 2017) of the correlation matrix for Sprout, Years, LAI 4%, LAI 5%, Canopy and Site openness, shows that factor 1 explained 62.6% of total variance while factor 2 explained 17.9% together explain 80.05% Communalities. For the year 2013, 2015 and 2017 respectively shows that there is a very strong correlation (p p < 0.0005) between LAI4 and LAI5.展开更多
Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature ...Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter (DBH) to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter (age) typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%-64.3%, 15 cm-75 cm, and 2.0-19.5 m, respectively. With increasing trunk diameter, the propor- tion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological charac- teristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter 〉1 m do not provide valu- able round wood for industries and cause to raise wood production costs. We recommend that these trees 〉1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.展开更多
With the present unceasing development of science and society,ecological and social functions of forest have attracted more and more attention.This study with Shenzhen City as an example through elaborating the concep...With the present unceasing development of science and society,ecological and social functions of forest have attracted more and more attention.This study with Shenzhen City as an example through elaborating the concepts and principles of ecological scenic forest and near-nature management,and combining with the present construction of ecological scenic forest in Shenzhen City,specifically stated the requirements,principles and implementation measures of different aspects involving in the construction of ecological scenic forest in Shenzhen,such as site classification,tree species selection,logging operation,community construction,tending management and benefit monitoring,and further expounded the application of near-nature management theories in this field.It was also stressed that the nature should be utilized and respected,artificial forest should be reformed into near-nature scenic forest with richer and more stable structure as well as higher protective eco-functions,so as to provide theoretical basis for the construction of ecological scenic forest and enhance its positive role in the urban construction of Shenzhen.展开更多
[Objective] The study was to analyze the forest landscape in Nanling Na- tional Nature Reserve to provide information for the protection of local forest ecosys- tems. [Method] With the documents of 1:10 000 topograph...[Objective] The study was to analyze the forest landscape in Nanling Na- tional Nature Reserve to provide information for the protection of local forest ecosys- tems. [Method] With the documents of 1:10 000 topographic maps, updated Forest Resource Inventory Data, based on the GIS platform and Fragstats software, the paper analyzed the patterns and heterogeneity of forest landscapes by adopting the landscape ecological theory and the method of landscape index. [Result] The forest landscape types, in terms of area occupation from large to small, are in the order of evergreen broad-leaved forest, coniferous mixed forest, evergreen and deciduous broad-leaved mixed forest, shrubs, mixed needle leaf forest, suitable land for forest deciduous broad-leaved forest and non-forest. [Conclusion] Overall, the Reserve had maintained sufficient forest landscape diversity with a low level fragmentation. The distribution of various types of forest landscape was extremely uneven, dominated by several types such as evergreen broad-leaved forest, coniferous forest, etc.展开更多
Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research applications.ALS is limited to obtaining fi ne structure information belo...Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research applications.ALS is limited to obtaining fi ne structure information below the forest canopy due to the occlusion of trees in natural forests.In contrast,TLS is unable to gather fi ne structure information about the upper canopy.To address the problem of incomplete acquisition of natural forest point cloud data by ALS and TLS on a single platform,this study proposes data registration without control points.The ALS and TLS original data were cropped according to sample plot size,and the ALS point cloud data was converted into relative coordinates with the center of the cropped data as the origin.The same feature point pairs of the ALS and TLS point cloud data were then selected to register the point cloud data.The initial registered point cloud data was fi nely and optimally registered via the iterative closest point(ICP)algorithm.The results show that the proposed method achieved highprecision registration of ALS and TLS point cloud data from two natural forest plots of Pinus yunnanensis Franch.and Picea asperata Mast.which included diff erent species and environments.An average registration accuracy of 0.06 m and 0.09 m were obtained for P.yunnanensis and P.asperata,respectively.展开更多
The carbon cycle of forest ecosystems plays a key role in regulating CO2 concentrations in the atmosphere. Research on carbon storage estimation of forest ecosystems has become a major research topic. However, carbon ...The carbon cycle of forest ecosystems plays a key role in regulating CO2 concentrations in the atmosphere. Research on carbon storage estimation of forest ecosystems has become a major research topic. However, carbon budgets of subtropical forest ecosystems have received little attention. Reports of soil carbon storage and topographic heterogeneity of carbon storage are limited. This study focused on the Jinggang Mountain National Nature Reserve as an example of a mid-subtropical forest and evaluated soil and vegetation carbon storage by field sampling combined with GIS, RS and GPS technology. We classified the forest into nine forest types using ALOS high-resolution remote sensing images. The evergreen broad-leaved forest has the largest area, occupying 26.5% of the total area, followed by coniferous and broad-leaved mixed forests and warm temperate coniferous forest, occupying 24.2 and 22.9%, respectively. The vegetation and soil carbon storage of the whole forest ecosystem were 1,692,344 and 5,514,707 t, with a carbon density of 7.4 and 24.2 kg/m^2, respectively, which suggests that the ecosystem has great carbon storage capacity. The topographic heterogeneity of the carbon storage was also analysed. The largest vegetation storage and soil storage is at 700–800 and 1000–1100 m, respectively. The vegetation carbon storage is highest in the southeast, south and southwest.展开更多
Centuries of forest exploitation have caused significant loss of natural forests in Europe,leading to a decline in populations for many species.To prevent further loss in biodiversity,the Norwegian government has set ...Centuries of forest exploitation have caused significant loss of natural forests in Europe,leading to a decline in populations for many species.To prevent further loss in biodiversity,the Norwegian government has set a target of protecting 10%of the forested area.However,recent data from the National Forest Inventory(NFI)reveals that less than 2%of Norway's forested area consists of natural forests.To identify forests with high conservation value,we used vertical and horizontal variables derived from airborne laser scanning(ALS)data,along with NFI plot measurements.Our study aimed to predict the presence of natural forests across three counties in southeastern Norway,using three different definitions:pristine,near-natural,and semi-natural forests.Natural forests are scarce,and their underrepresentation in field reference data can compromise the accuracy of the predictions.To address this,we assessed the potential gain of including additional field data specifically targeting natural forests to achieve a better balance in the dataset.Additionally,we examined the impact of stratifying the data by dominant tree species on the performance of the models.Our results revealed that semi-natural forests were the most accurately predicted,followed by near-natural and pristine forests,with Matthews correlation coefficient values of 0.32,0.24,and 0.17,respectively.Including additional field data did not improve the predictions.However,stratification by species improved the accuracy of predictions for near-natural and semi-natural forests,while reducing accuracy for pristine forests.The use of horizontal variables did not improve the predictions.Our study demonstrates the potential of ALS data in identifying forests with high conservation value.It provides a basis for further research on the use of ALS data for the detection and conservation of natural forests,offering valuable insights to guide future forest preservation efforts.展开更多
In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structur...In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed.In particular,we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans.The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests.The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height.Moreover,the influence of crown length is greater than that of tree height.There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree,with an average intersection of neighboring crowns reaching 80%.The rank rating of natural forest sample plots is correlated with the optimal solution distance model,and their results are generally consistent for natural forests.However,the rank rating is not able to provide a quantitative assessment.The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands.It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point,and accurately assesses the forest spatial structure.The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.展开更多
Landscape change and its driving forces are always one of the major issues in landscape ecology. In this paper,we investigated the landscape pattern of Nanling National Nature Reserve using TM data and forest stand ma...Landscape change and its driving forces are always one of the major issues in landscape ecology. In this paper,we investigated the landscape pattern of Nanling National Nature Reserve using TM data and forest stand map. The paper aims at exploring how and why the landscape changed form 1988 to 2009. The results indicated that: the major landscape types are evergreen broad-leaved forest and coniferous forests,the area ratio of both total more than 80%; area ratio of other landscape types is less than 10%,including mainly mixed coniferous and broad-leaved forest,deciduous forest,shrub,other woodland,cultivated land,other land,construction land and water. During the 20 years,evergreen broad-leaved forest landscape has become a large-scale substrate,coniferous forests are interspersed,a small area of mixed coniferous and broad-leaved mixed forest patches expands; forest area in the study area changes slightly,the number of blocks increases,the degree of landscape fragmentation increases; forest landscapes change,and are less affected by human activities,which is closely related to the establishment,management and protection of protected areas.展开更多
The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, ...The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, the world′s most populous nation supporting some of the most valuable biodiversity hotspots in the world. In this study, we conducted a long-term and large-scale analysis of the effectiveness of 20 of the earliest nature reserves established in Hainan Province, an island home to among the highest concentration of plants and animals in China. Remote sensing imagery from 1988, 1998, and 2008 were analyzed to investigate the temporal and spatial changes of natural forests in these nature reserves and surrounding areas. We also conducted transition matrix analysis and principle component analysis to identify the driving factors that affect the protection effectiveness of nature reserves. The results were as follows: 1) During the 20-year period from 1988 to 2008, natural forests coverage of the 20 studied nature reserves dropped 2.34 percentage points, whereas the natural forests coverage dropped 11.31 percentage points in a 0–5 km outside reserve buffer and 9.36 percentage points in a 5–10 km outside reserve buffer, indicating a significant inhibitory effect of the nature reserves on the loss of natural forests. 2) Natural forests coverage dropped in 60% of the studied nature reserves during the 20-year period, suggesting a poor protection effectiveness of these reserves, while the coverage proportion showed some increase(0%/yr–5%/yr) in other reserves. 3) Expansion of rubber and pulp forests as part of a booming economy were the main factors affecting the effectiveness of the nature reserves for conserving natural forests in Hainan Province. The results of this study provide an important empirical basis for the protection of natural forests in Hainan Province, which can be used as a blueprint for nature reserve evaluation in other places in China.展开更多
The grottoes here are like gems studded along the Silk Road,and the natural scenery formed by tranquil valleys,springs and streams,imposing peaks,wafting sea of clouds,and dense forests attracts streams of tourists.
An improved understanding of biodiversity-productivity relationships(BPRs)along environmental gradients is crucial for effective ecosystem management and biodiversity conservation.The stress-gradient hypothesis sugges...An improved understanding of biodiversity-productivity relationships(BPRs)along environmental gradients is crucial for effective ecosystem management and biodiversity conservation.The stress-gradient hypothesis suggests that BPRs are stronger in stressful environments compared to more favorable conditions.However,there is limited knowledge regarding the variation of BPRs along elevational gradients and their generality across different landscapes.To study how BPRs change with elevation,we harnessed inventory data on 6,431 trees from152 plots surveyed twice in eight to ten year intervals in mountain forests of temperate Europe and subtropical Asia.We quantified the relationship between aboveground productivity and different biodiversity measures,including taxonomic,functional,and phylogenetic diversity.To elucidate the processes underlying BPRs,we studied the variation of different functional traits along elevation across landscapes.We found no general pattern of BPRs across landscapes and elevations.Relationships were neutral for all biodiversity measures in temperate forests,and negative for taxonomic and functional diversity in subtropical forests.BPRs were largely congruent between taxonomic,functional and phylogenetic diversity.We found only weak support for the stress-gradient hypothesis,with BPRs turning from negative to positive(effect not significant)close to the tree line in subtropical forests.In temperate forests,however,elevation patterns were strongly modulated by species identity effects as influenced by specific traits.The effect of traits such as community-weighted mean of maximum plant height and wood density on productivity was congruent across landscapes.Our study highlights the context-dependence of BPRs across elevation gradients and landscapes.Species traits are key modulating factors of BPRs and should be considered more explicitly in studies of the functional role of biodiversity.Furthermore,our findings highlight that potential trade-offs between conserving biodiversity and fostering ecosystem productivity exist,which require more attention in policy and management.展开更多
The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in trees.One possible origin of ...The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in trees.One possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced leaves.However,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly documented.An experiment in a beech forest in Meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence period.The aim was to identify potential nutritional consequences of droughts for trees.Monitoring nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(i.e.resorption efficiency),thus reducing the K reserve in trees for the next growing season.This result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study site.Reduced foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(P)were also observed.In addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree nutrition.The calcium(Ca)negative resorption decreased,with no apparent consequence in our study site.Our results show that nutrient exchanges in the canopy and the partitioning of the green leaf pool can be modified by drought events,and may have consequences on tree nutrition.展开更多
This study comprehensively assessed long-term vegetation changes and forest fragmentation dynamics in the Himalayan temperate region of Pakistan from 1989 to 2019.Four satellite images,including Landsat-5 TM and Lands...This study comprehensively assessed long-term vegetation changes and forest fragmentation dynamics in the Himalayan temperate region of Pakistan from 1989 to 2019.Four satellite images,including Landsat-5 TM and Landsat-8 Operational Land Imager(OLI),were chosen for subsequent assessments in October 1989,2001,2011 and 2019.The classified maps of 1989,2001,2011 and 2019 were created using the maximum likelihood classifier.Post-classification comparison showed an overall accuracy of 82.5%and a Kappa coefficient of 0.79 for the 2019 map.Results revealed a drastic decrease in closed-canopy and open-canopy forests by 117.4 and 271.6 km^(2),respectively,and an increase in agriculture/farm cultivation by 1512.8 km^(2).The two-way ANOVA test showed statistically significant differences in the area of various cover classes.Forest fragmentation was evaluated using the Landscape Fragmentation Tool(LFT v2.0)between 1989 and 2019.The large forest core(>2.00 km^(2))decreased from 149.4 to 296.7 km^(2),and a similar pattern was observed in medium forest core(1.00-2.00 km^(2))forests.On the contrary,the small core(<1.00 km^(2))forest increased from 124.8 to 145.3 km^(2) in 2019.The perforation area increased by 296.9 km^(2),and the edge effect decreased from 458.9 to 431.7 km^(2).The frequency of patches also increased by 119.1 km^(2).The closed and open canopy classes showed a decreasing trend with an annual rate of 0.58%and 1.35%,respectively.The broad implications of these findings can be seen in the studied region as well as other global ecological areas.They serve as an imperative baseline for afforestation and reforestation operations,highlighting the urgent need for efficient management,conservation,and restoration efforts.Based on these findings,sustainable land-use policies may be put into place that support local livelihoods,protect ecosystem services,and conserve biodiversity.展开更多
Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importanc...Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.展开更多
The forest ecological system fulfills many important ecological functions. Researches on the analysis and valuation on forest ecosystem services are at the cutting edge of current ecology and ecological economics. Bas...The forest ecological system fulfills many important ecological functions. Researches on the analysis and valuation on forest ecosystem services are at the cutting edge of current ecology and ecological economics. Based on the calculation method of service value of forest ecosystem, 7 forest ecosystem services of Nanling National Nature Reserve were valued, totaling 703.48 million yuan/year. In terms of the contribution size of the service value of forest ecosystem, carbon fixation and oxygen release came as the greatest one, followed by conservation of soil, purification of the air, biodiversity conservation, conservation of water, accumulation of nutrients, and forest recreation. With its value of 208.46 million yuan, carbon fixation and oxygen release ranked first, accounting for 29.63% of the total value; conservation of soil of 24.67% service value took the second place; purification of the air came in third in the value rankings, representing 22.55% of the total value; the fourth one was biodiversity conservation, whose service value came up to 14.51%. Those 4 services made up 91.36% of the total value while other 3 services ranging from conservation of water, accumulation of nutrients to forest recreation were merely a small proportion. This is because the Nanling National Nature Reserve is essentially a large oxygen bar. The above-mentioned ecosystem valuation method contributes to the understanding of the overall value of the forest ecosystem as well as the implementation and advancement in the regional sustainable development strategy.展开更多
In order to clarify the service function and value of forest ecosystem in Kanas Nature Reserve, the ecological service function and its value of forest ecosystem in Kanas Nature Reserve in 2009 and 2014 were evaluated...In order to clarify the service function and value of forest ecosystem in Kanas Nature Reserve, the ecological service function and its value of forest ecosystem in Kanas Nature Reserve in 2009 and 2014 were evaluated by using the method of Specifications for Assessment of Forest Ecosystem Services in China(LY/T 1721-2008). The results showed that in 2014, the total value of forest ecosystem service function in Kanas Nature Reserve increased by 7.34% compared with that in 2009, and the value of water conservation and biodiversity accounted for the largest proportion. The increasing rate of functional value of shrub forest land was obviously higher than that of coniferous forest land and broad-leaf forest land. The service function and value of different forest types were obviously different.展开更多
3S technology was applied to analyze spatio-temporal changes of landscape pattern in Nanling National Nature Reserve and the driving forces. The results showed that the study area was dominated by forest landscape fro...3S technology was applied to analyze spatio-temporal changes of landscape pattern in Nanling National Nature Reserve and the driving forces. The results showed that the study area was dominated by forest landscape from 1988 to 2009, accounting for 95% of the total area, among all forest landscapes, evergreen broadleaved forest accounted for the largest ratio(>50%). In terms of landscape fragmentation, landscape density index of the study area increased, landscape fragmentation was aggravated; patch density of core zone declined slightly, mean patch area of all landscape types increased, landscape fragmentation decreased slightly; buffer zone and experimental zone witnessed the aggravation of fragmentation. In terms of landscape diversity, landscape pattern of the study area became increasingly complex, diversity index increased, landscape heterogenization was enhanced; landscape diversity of the core zone increased slightly, that of the buffer zone increased greatly, but that of the experimental zone declined and landscape heterogenization reduced. Landscapes in the whole area grew more diversified, while landscape pattern of the core zone was simplified, that of the buffer zone witnessed slight changes, and that of the experimental zone kept consistent with that of the study area. In terms of driving forces of landscape pattern change, natural factors have contributed to the landscape changes in the study area, but human factors such as forest management, forest tourism, local residents an economic factors played a dominant role. With the increasing external interventions to the landscape pattern change, the contradiction between landscape eco-environment protection and resource development and utilization in Nanling National Nature Reserve will be increasingly sharpened.展开更多
基金support by Melbourne International Research Scholarship (MIRS)。
文摘Understanding how past disturbances have influenced the development of forests is critical for deciphering their current structure and composition and forecasting future changes.In this study,dendrochronological methods were applied to uncover the disturbance history of old-growth hemlock-dominated forests in central Bhutan.Analysis of tree-ring samples from two old-growth hemlock stands,located in two different topographic settings,identified the importance of gap-phase dynamics in facilitating recruitment and growth releases and producing complex,multi-aged structure s over time.One site showed evidence of a near stand-replacing disturbance in the late 1700s,while the other showed no evide nce of high-severity disturbance at any time over the last 400 years.At both sites low-to medium-severity disturbances,some of which appear to be associated with cyclones originating in the Bay of Bengal,dominated the disturbance regime.The hemlock stands exhibited a significant positive association between cyclone occurrence and growth release events and between recruitment pulses and growth release events.From 1800 to 1970 there was an increase in recruitment of angiosperm tree species at most sites and a corresponding decline in conifer recruitment.Over the past 50 years there has been little new recruitment;this may be due to light limitation in the understory from shade-tolerant angiosperms and bamboo in the lower strata of these stands.Significant variations in disturbance dynamics and recruitment were observed across the study sites,suggesting that other factors,such as topography and climate,may be influencing long-term stand development patterns.This study highlights the complex interplay between historical disturbance regimes and tree recruitment in shaping the age and size structures of old-growth hemlock forests in central Bhutan.It also provides new insights into the dynamics of these forests that can be used to support effective forest conservation and management in the future.
基金supported by the National Natural Science Foundation of China(Grants 31971463,31930078)the National Key R&D Program of China(Grant 2021YFD2200402)the Chinese Academy of Forestry(Grant CAFYBB2020ZA001).
文摘Different chemical compositions of soil organic carbon(SOC)affect its persistence and whether it signifi-cantly differs between natural forests and plantations remains unclear.By synthesizing 234 observations of SOC chemical compositions,we evaluated global patterns of concentra-tion,individual chemical composition(alkyl C,O-alkyl C,aromatic C,and carbonyl C),and their distribution even-ness.Our results indicate a notably higher SOC,a markedly larger proportion of recalcitrant alkyl C,and lower easily decomposed carbonyl C proportion in natural forests.How-ever,SOC chemical compositions were appreciably more evenly distributed in plantations.Based on the assumed con-ceptual index of SOC chemical composition evenness,we deduced that,compared to natural forests,plantations may have higher possible resistance to SOC decomposition under disturbances.In tropical regions,SOC levels,recalcitrant SOC chemical composition,and their distributed evenness were significantly higher in natural forests,indicating that SOC has higher chemical stability and possible resistance to decomposition.Climate factors had minor effects on alkyl C in forests globally,while they notably affected SOC chemi-cal composition in tropical forests.This could contribute to the differences in chemical compositions and their distrib-uted evenness between plantations and natural stands.
文摘Examining the contribution of hemispherical photographs in the understanding of Natural forest regeneration is very important in estimating the future forest structure, composition and to enforce conservation regulations. This study sets out to examine the interaction between stump sprouting, LAI, site and canopy openness for the entire AKAK forest area and for the logging compartments;2013, 2015 and 2017 respectively. 49 sprouted stump were identified randonly. 20 m × 20 m plots were demarcated along a canopy gaps for each sprouted stump, the plots were established in such a manner that the sprouted stumps will be in the middle. For each of the selected 49 sprouted stump, indirect measurements of canopy cover were performed in the 49 plots of 20 m × 20 m (0.04 ha), giving a total of 1.96 ha of land covered. Galaxy S3 smartphone with a built-in Infinix ZERO 4 fish-eye lens with 198˚ view angle equidistant projection was used to take photos. The fish-eye lens was mounted on the phone camera and photograph were taken at a fixed height of 1.3 m. Results revealed that, the combine Principal Component Factor Analysis (2013, 2015 and 2017) of the correlation matrix for Sprout, Years, LAI 4%, LAI 5%, Canopy and Site openness, shows that factor 1 explained 62.6% of total variance while factor 2 explained 17.9% together explain 80.05% Communalities. For the year 2013, 2015 and 2017 respectively shows that there is a very strong correlation (p p < 0.0005) between LAI4 and LAI5.
文摘Oriental Beech is the most important commercial tree species in northern Iran. In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation. Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter (DBH) to amount of decay. Based on the location of onset of decay, we categorized three types of decay as stump, stem, and crown decay. Trees of greater diameter (age) typically showed greater decay in the stem. Percent of decayed volume, diameter of decayed tissue, and length of decay in tree stems varied between 0.5%-64.3%, 15 cm-75 cm, and 2.0-19.5 m, respectively. With increasing trunk diameter, the propor- tion of truck decay increased. Red heart and dark red heart constituted 25% and 14.3% of sampled trees, respectively. However, we found no correlation between intensity of stem decay and morphological charac- teristics of trees. Seedlings were not abundant around the bases of over-mature trees, suggesting that the trees did not contribute to regeneration of the stand. Beech trees of diameter 〉1 m do not provide valu- able round wood for industries and cause to raise wood production costs. We recommend that these trees 〉1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.
基金Sponsored by International Scientific and Technological Cooperation Project of Ministry of Science and Technology(2007DFA31070)Specialized Fund of Basic S&T Expenses for Central Government Level Research Institutes of Public Interest(CAFYBB2008004)~~
文摘With the present unceasing development of science and society,ecological and social functions of forest have attracted more and more attention.This study with Shenzhen City as an example through elaborating the concepts and principles of ecological scenic forest and near-nature management,and combining with the present construction of ecological scenic forest in Shenzhen City,specifically stated the requirements,principles and implementation measures of different aspects involving in the construction of ecological scenic forest in Shenzhen,such as site classification,tree species selection,logging operation,community construction,tending management and benefit monitoring,and further expounded the application of near-nature management theories in this field.It was also stressed that the nature should be utilized and respected,artificial forest should be reformed into near-nature scenic forest with richer and more stable structure as well as higher protective eco-functions,so as to provide theoretical basis for the construction of ecological scenic forest and enhance its positive role in the urban construction of Shenzhen.
基金Supported by Digital Monitoring and Management Platform Project in Nanling National Nature Reserve(GDHS13SGHG05025)~~
文摘[Objective] The study was to analyze the forest landscape in Nanling Na- tional Nature Reserve to provide information for the protection of local forest ecosys- tems. [Method] With the documents of 1:10 000 topographic maps, updated Forest Resource Inventory Data, based on the GIS platform and Fragstats software, the paper analyzed the patterns and heterogeneity of forest landscapes by adopting the landscape ecological theory and the method of landscape index. [Result] The forest landscape types, in terms of area occupation from large to small, are in the order of evergreen broad-leaved forest, coniferous mixed forest, evergreen and deciduous broad-leaved mixed forest, shrubs, mixed needle leaf forest, suitable land for forest deciduous broad-leaved forest and non-forest. [Conclusion] Overall, the Reserve had maintained sufficient forest landscape diversity with a low level fragmentation. The distribution of various types of forest landscape was extremely uneven, dominated by several types such as evergreen broad-leaved forest, coniferous forest, etc.
基金supported by the National Natural Science Foundation of China,Grant Number 41961060by the Program for Innovative Research Team (in Science and Technology) in the University of Yunnan Province,Grant Number IRTSTYN+1 种基金by the Scientific Research Fund Project of the Education Department of Yunnan Province,Grant Numbers 2020J0256 and 2021J0438by the Postgraduate Scientific Research and Innovation Fund Project of Yunnan Normal University,Grant Number YJSJJ21-A08
文摘Airborne laser scanning(ALS)and terrestrial laser scanning(TLS)has attracted attention due to their forest parameter investigation and research applications.ALS is limited to obtaining fi ne structure information below the forest canopy due to the occlusion of trees in natural forests.In contrast,TLS is unable to gather fi ne structure information about the upper canopy.To address the problem of incomplete acquisition of natural forest point cloud data by ALS and TLS on a single platform,this study proposes data registration without control points.The ALS and TLS original data were cropped according to sample plot size,and the ALS point cloud data was converted into relative coordinates with the center of the cropped data as the origin.The same feature point pairs of the ALS and TLS point cloud data were then selected to register the point cloud data.The initial registered point cloud data was fi nely and optimally registered via the iterative closest point(ICP)algorithm.The results show that the proposed method achieved highprecision registration of ALS and TLS point cloud data from two natural forest plots of Pinus yunnanensis Franch.and Picea asperata Mast.which included diff erent species and environments.An average registration accuracy of 0.06 m and 0.09 m were obtained for P.yunnanensis and P.asperata,respectively.
基金supported by the National Natural Science Foundation of China(41701209,41501095,41601198)
文摘The carbon cycle of forest ecosystems plays a key role in regulating CO2 concentrations in the atmosphere. Research on carbon storage estimation of forest ecosystems has become a major research topic. However, carbon budgets of subtropical forest ecosystems have received little attention. Reports of soil carbon storage and topographic heterogeneity of carbon storage are limited. This study focused on the Jinggang Mountain National Nature Reserve as an example of a mid-subtropical forest and evaluated soil and vegetation carbon storage by field sampling combined with GIS, RS and GPS technology. We classified the forest into nine forest types using ALOS high-resolution remote sensing images. The evergreen broad-leaved forest has the largest area, occupying 26.5% of the total area, followed by coniferous and broad-leaved mixed forests and warm temperate coniferous forest, occupying 24.2 and 22.9%, respectively. The vegetation and soil carbon storage of the whole forest ecosystem were 1,692,344 and 5,514,707 t, with a carbon density of 7.4 and 24.2 kg/m^2, respectively, which suggests that the ecosystem has great carbon storage capacity. The topographic heterogeneity of the carbon storage was also analysed. The largest vegetation storage and soil storage is at 700–800 and 1000–1100 m, respectively. The vegetation carbon storage is highest in the southeast, south and southwest.
基金funding under the umbrella of ERA-NET Cofund ForestValue project NOBEL,“Novel business models and mechanisms for the sustainable supply of and payment for forest ecosystem services”ForestValue was funded by the European Union's Horizon 2020 research and innovation program(grant number 773324)+1 种基金Furthermore,the Norwegian Environment Agency funded the collection of the additional plots as a part of the project“Remote sensing-based mapping and monitoring of the forest ecosystem”(grant number 18087221)supported by the Norwegian Research Council(project number 297883).
文摘Centuries of forest exploitation have caused significant loss of natural forests in Europe,leading to a decline in populations for many species.To prevent further loss in biodiversity,the Norwegian government has set a target of protecting 10%of the forested area.However,recent data from the National Forest Inventory(NFI)reveals that less than 2%of Norway's forested area consists of natural forests.To identify forests with high conservation value,we used vertical and horizontal variables derived from airborne laser scanning(ALS)data,along with NFI plot measurements.Our study aimed to predict the presence of natural forests across three counties in southeastern Norway,using three different definitions:pristine,near-natural,and semi-natural forests.Natural forests are scarce,and their underrepresentation in field reference data can compromise the accuracy of the predictions.To address this,we assessed the potential gain of including additional field data specifically targeting natural forests to achieve a better balance in the dataset.Additionally,we examined the impact of stratifying the data by dominant tree species on the performance of the models.Our results revealed that semi-natural forests were the most accurately predicted,followed by near-natural and pristine forests,with Matthews correlation coefficient values of 0.32,0.24,and 0.17,respectively.Including additional field data did not improve the predictions.However,stratification by species improved the accuracy of predictions for near-natural and semi-natural forests,while reducing accuracy for pristine forests.The use of horizontal variables did not improve the predictions.Our study demonstrates the potential of ALS data in identifying forests with high conservation value.It provides a basis for further research on the use of ALS data for the detection and conservation of natural forests,offering valuable insights to guide future forest preservation efforts.
基金funded by National Key Research and development project(2022YFD2201001)。
文摘In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed.In particular,we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans.The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests.The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height.Moreover,the influence of crown length is greater than that of tree height.There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree,with an average intersection of neighboring crowns reaching 80%.The rank rating of natural forest sample plots is correlated with the optimal solution distance model,and their results are generally consistent for natural forests.However,the rank rating is not able to provide a quantitative assessment.The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands.It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point,and accurately assesses the forest spatial structure.The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.
文摘Landscape change and its driving forces are always one of the major issues in landscape ecology. In this paper,we investigated the landscape pattern of Nanling National Nature Reserve using TM data and forest stand map. The paper aims at exploring how and why the landscape changed form 1988 to 2009. The results indicated that: the major landscape types are evergreen broad-leaved forest and coniferous forests,the area ratio of both total more than 80%; area ratio of other landscape types is less than 10%,including mainly mixed coniferous and broad-leaved forest,deciduous forest,shrub,other woodland,cultivated land,other land,construction land and water. During the 20 years,evergreen broad-leaved forest landscape has become a large-scale substrate,coniferous forests are interspersed,a small area of mixed coniferous and broad-leaved mixed forest patches expands; forest area in the study area changes slightly,the number of blocks increases,the degree of landscape fragmentation increases; forest landscapes change,and are less affected by human activities,which is closely related to the establishment,management and protection of protected areas.
基金Under the auspices of Nationwide Remote Sensing Survey and Evaluation on Ecological Environment Change in 2000–2010(No.STSN-04-00)
文摘The establishment of nature reserves is a key approach for biodiversity conservation worldwide. However, there is a lack of unified methodology to evaluate the effectiveness of nature reserves, particularly in China, the world′s most populous nation supporting some of the most valuable biodiversity hotspots in the world. In this study, we conducted a long-term and large-scale analysis of the effectiveness of 20 of the earliest nature reserves established in Hainan Province, an island home to among the highest concentration of plants and animals in China. Remote sensing imagery from 1988, 1998, and 2008 were analyzed to investigate the temporal and spatial changes of natural forests in these nature reserves and surrounding areas. We also conducted transition matrix analysis and principle component analysis to identify the driving factors that affect the protection effectiveness of nature reserves. The results were as follows: 1) During the 20-year period from 1988 to 2008, natural forests coverage of the 20 studied nature reserves dropped 2.34 percentage points, whereas the natural forests coverage dropped 11.31 percentage points in a 0–5 km outside reserve buffer and 9.36 percentage points in a 5–10 km outside reserve buffer, indicating a significant inhibitory effect of the nature reserves on the loss of natural forests. 2) Natural forests coverage dropped in 60% of the studied nature reserves during the 20-year period, suggesting a poor protection effectiveness of these reserves, while the coverage proportion showed some increase(0%/yr–5%/yr) in other reserves. 3) Expansion of rubber and pulp forests as part of a booming economy were the main factors affecting the effectiveness of the nature reserves for conserving natural forests in Hainan Province. The results of this study provide an important empirical basis for the protection of natural forests in Hainan Province, which can be used as a blueprint for nature reserve evaluation in other places in China.
文摘The grottoes here are like gems studded along the Silk Road,and the natural scenery formed by tranquil valleys,springs and streams,imposing peaks,wafting sea of clouds,and dense forests attracts streams of tourists.
基金supported by the Sino-German Postdoc Scholarship Program of the China Scholarship Council(CSC)the German Academic Exchange Service(DAAD)+4 种基金supported in part by the National Natural Science Foundation of China(Nos.32071541,41971071)the Ministry of Science and Technology of China(Nos.2021FY100200,2021FY100702,2023YFF0805802)the Youth Innovation Promotion Association,CAS(No.2021392)the International Partnership Program,CAS(No.151853KYSB20190027)the“Climate Change Research Initiative of the Bavarian National Parks”funded by the Bavarian State Ministry of the Environment and Consumer Protection.
文摘An improved understanding of biodiversity-productivity relationships(BPRs)along environmental gradients is crucial for effective ecosystem management and biodiversity conservation.The stress-gradient hypothesis suggests that BPRs are stronger in stressful environments compared to more favorable conditions.However,there is limited knowledge regarding the variation of BPRs along elevational gradients and their generality across different landscapes.To study how BPRs change with elevation,we harnessed inventory data on 6,431 trees from152 plots surveyed twice in eight to ten year intervals in mountain forests of temperate Europe and subtropical Asia.We quantified the relationship between aboveground productivity and different biodiversity measures,including taxonomic,functional,and phylogenetic diversity.To elucidate the processes underlying BPRs,we studied the variation of different functional traits along elevation across landscapes.We found no general pattern of BPRs across landscapes and elevations.Relationships were neutral for all biodiversity measures in temperate forests,and negative for taxonomic and functional diversity in subtropical forests.BPRs were largely congruent between taxonomic,functional and phylogenetic diversity.We found only weak support for the stress-gradient hypothesis,with BPRs turning from negative to positive(effect not significant)close to the tree line in subtropical forests.In temperate forests,however,elevation patterns were strongly modulated by species identity effects as influenced by specific traits.The effect of traits such as community-weighted mean of maximum plant height and wood density on productivity was congruent across landscapes.Our study highlights the context-dependence of BPRs across elevation gradients and landscapes.Species traits are key modulating factors of BPRs and should be considered more explicitly in studies of the functional role of biodiversity.Furthermore,our findings highlight that potential trade-offs between conserving biodiversity and fostering ecosystem productivity exist,which require more attention in policy and management.
基金supported by the Lorraine University of Excellence via the DEEPSURF project(ANR 70315-IDEX-04-LUE)。
文摘The increase in the frequency and intensity of drought events expected in the coming decades in Western Europe may disturb forest biogeochemical cycles and create nutrient deficiencies in trees.One possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced leaves.However,the effects of drought events on this partitioning and the consequences for the maintenance of tree nutrition are poorly documented.An experiment in a beech forest in Meuse(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence period.The aim was to identify potential nutritional consequences of droughts for trees.Monitoring nutrient dynamics,including resorption,chemistry of green and senesced leaves,foliar absorption and leaching in mature beech stands from 2012 to 2019 allowed us to compare the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by almost a third of the potassium(K)partitioning to resorption(i.e.resorption efficiency),thus reducing the K reserve in trees for the next growing season.This result suggests that with the increased drought frequency and intensity expected for the coming decades,there will be a risk of potassium deficiency in trees,as already observed in a rainfall exclusion experiment on the same study site.Reduced foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(P)were also observed.In addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is more likely to improve tree nutrition.The calcium(Ca)negative resorption decreased,with no apparent consequence in our study site.Our results show that nutrient exchanges in the canopy and the partitioning of the green leaf pool can be modified by drought events,and may have consequences on tree nutrition.
基金This research was supported by project number(RSP2024R384)King Saud University,Riyadh,Saudi Arabia.
文摘This study comprehensively assessed long-term vegetation changes and forest fragmentation dynamics in the Himalayan temperate region of Pakistan from 1989 to 2019.Four satellite images,including Landsat-5 TM and Landsat-8 Operational Land Imager(OLI),were chosen for subsequent assessments in October 1989,2001,2011 and 2019.The classified maps of 1989,2001,2011 and 2019 were created using the maximum likelihood classifier.Post-classification comparison showed an overall accuracy of 82.5%and a Kappa coefficient of 0.79 for the 2019 map.Results revealed a drastic decrease in closed-canopy and open-canopy forests by 117.4 and 271.6 km^(2),respectively,and an increase in agriculture/farm cultivation by 1512.8 km^(2).The two-way ANOVA test showed statistically significant differences in the area of various cover classes.Forest fragmentation was evaluated using the Landscape Fragmentation Tool(LFT v2.0)between 1989 and 2019.The large forest core(>2.00 km^(2))decreased from 149.4 to 296.7 km^(2),and a similar pattern was observed in medium forest core(1.00-2.00 km^(2))forests.On the contrary,the small core(<1.00 km^(2))forest increased from 124.8 to 145.3 km^(2) in 2019.The perforation area increased by 296.9 km^(2),and the edge effect decreased from 458.9 to 431.7 km^(2).The frequency of patches also increased by 119.1 km^(2).The closed and open canopy classes showed a decreasing trend with an annual rate of 0.58%and 1.35%,respectively.The broad implications of these findings can be seen in the studied region as well as other global ecological areas.They serve as an imperative baseline for afforestation and reforestation operations,highlighting the urgent need for efficient management,conservation,and restoration efforts.Based on these findings,sustainable land-use policies may be put into place that support local livelihoods,protect ecosystem services,and conserve biodiversity.
基金financially supported by the Innovation Foundation for Doctoral Program of Forestry Engineering of Northeast Forestry University,grant number:LYGC202117the China Scholarship Council(CSC),grant number:202306600046+1 种基金the Research and Development Plan of Applied Technology in Heilongjiang Province of China,grant number:GA19C006Research and Demonstration on Functional Improvement Technology of Forest Ecological Security Barrier in Heilongjiang Province,grant number:GA21C030。
文摘Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.
文摘The forest ecological system fulfills many important ecological functions. Researches on the analysis and valuation on forest ecosystem services are at the cutting edge of current ecology and ecological economics. Based on the calculation method of service value of forest ecosystem, 7 forest ecosystem services of Nanling National Nature Reserve were valued, totaling 703.48 million yuan/year. In terms of the contribution size of the service value of forest ecosystem, carbon fixation and oxygen release came as the greatest one, followed by conservation of soil, purification of the air, biodiversity conservation, conservation of water, accumulation of nutrients, and forest recreation. With its value of 208.46 million yuan, carbon fixation and oxygen release ranked first, accounting for 29.63% of the total value; conservation of soil of 24.67% service value took the second place; purification of the air came in third in the value rankings, representing 22.55% of the total value; the fourth one was biodiversity conservation, whose service value came up to 14.51%. Those 4 services made up 91.36% of the total value while other 3 services ranging from conservation of water, accumulation of nutrients to forest recreation were merely a small proportion. This is because the Nanling National Nature Reserve is essentially a large oxygen bar. The above-mentioned ecosystem valuation method contributes to the understanding of the overall value of the forest ecosystem as well as the implementation and advancement in the regional sustainable development strategy.
基金Sponsored by Monitoring and Assessment of Forestry Ecological Service Function in Xinjiang(xjlk(2013)001)Open Fund of Forest Ecosystem Positioning Research Station in Altai mountain,Xinjiang
文摘In order to clarify the service function and value of forest ecosystem in Kanas Nature Reserve, the ecological service function and its value of forest ecosystem in Kanas Nature Reserve in 2009 and 2014 were evaluated by using the method of Specifications for Assessment of Forest Ecosystem Services in China(LY/T 1721-2008). The results showed that in 2014, the total value of forest ecosystem service function in Kanas Nature Reserve increased by 7.34% compared with that in 2009, and the value of water conservation and biodiversity accounted for the largest proportion. The increasing rate of functional value of shrub forest land was obviously higher than that of coniferous forest land and broad-leaf forest land. The service function and value of different forest types were obviously different.
基金Sponsored by Digital Monitoring,Management and Protection Program of Nanling National Nature Reserve(GDHS13SGHG05025)
文摘3S technology was applied to analyze spatio-temporal changes of landscape pattern in Nanling National Nature Reserve and the driving forces. The results showed that the study area was dominated by forest landscape from 1988 to 2009, accounting for 95% of the total area, among all forest landscapes, evergreen broadleaved forest accounted for the largest ratio(>50%). In terms of landscape fragmentation, landscape density index of the study area increased, landscape fragmentation was aggravated; patch density of core zone declined slightly, mean patch area of all landscape types increased, landscape fragmentation decreased slightly; buffer zone and experimental zone witnessed the aggravation of fragmentation. In terms of landscape diversity, landscape pattern of the study area became increasingly complex, diversity index increased, landscape heterogenization was enhanced; landscape diversity of the core zone increased slightly, that of the buffer zone increased greatly, but that of the experimental zone declined and landscape heterogenization reduced. Landscapes in the whole area grew more diversified, while landscape pattern of the core zone was simplified, that of the buffer zone witnessed slight changes, and that of the experimental zone kept consistent with that of the study area. In terms of driving forces of landscape pattern change, natural factors have contributed to the landscape changes in the study area, but human factors such as forest management, forest tourism, local residents an economic factors played a dominant role. With the increasing external interventions to the landscape pattern change, the contradiction between landscape eco-environment protection and resource development and utilization in Nanling National Nature Reserve will be increasingly sharpened.