The red-edge bands and their derived vegetation indices play a crucial role in monitoring vegetation health.The Gaofen-6(GF-6)and Sentinel-2A satellites are equipped with two and three red-edge bands,respectively,thus...The red-edge bands and their derived vegetation indices play a crucial role in monitoring vegetation health.The Gaofen-6(GF-6)and Sentinel-2A satellites are equipped with two and three red-edge bands,respectively,thus making them invaluable for monit-oring forest health.To compare the performance of these two satellites’red-edge bands in monitoring forest health,this study selected forests in Liuyang City,Hunan Province and Tonggu County,Jiangxi Province and Hanzhong City,Shaanxi Province in China as study areas and used three commonly used red-edge indices and the Random Forest(RF)algorithm for the comparison.The three selected red-edge indices were the Normalized Difference Red-Edge Index 1(NDRE1),the Missouri emergency resource information system Ter-restrial Chlorophyll Index(MTCI),and the Inverted Red-Edge Chlorophyll Index(IRECI).Through training of sample regions,this study determined the spectral differences among three forest health levels and established classification criteria for these levels.The res-ults showed that GF-6 imagery provided higher accuracy in distinguishing forest health levels than Sentinel-2A,with an average accur-acy of 90.22%versus 76.55%.This difference is attributed to variations in the wavelengths used to construct the red-edge indices between GF-6 and Sentinel-2A.In the RF algorithm,this study employed three distinct band combinations for classification:all bands including red-edge bands,excluding red-edge bands,and only red-edge bands.The results indicated that GF-6 outperformed Sentinel-2A when using the first and second band combinations,yet slightly underperforming with the third.This outcome was closely associ-ated with the importance of each band’s contribution to classification accuracy reveled by the Gini importance score,their sensitivity in detecting forest health conditions,and the total number of bands employed in the classification process.Overall,the NDRE1 derived from GF-6 achieved the highest average accuracy(90.22%).This study provides a scientific basis for selecting appropriate remote sens-ing data and techniques for forest health monitoring,which is of significant importance for the future ecological protection of forests.展开更多
Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area...Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley The newly introduced P. radiata are exposed to two kinds of forest health risks： they may be attacked by （a） indigenous pathogens and pests against which they may not possess any resistance or （b） by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical appmach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding conifemus forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are pmvided to improve forest vigour and to reduce the forest health risks posed by indigenous as well as exotic pests and pathogens to the introduced P. radiata. Ways to increase the ability to manage the forest health risks once a particular pest infestation and disease eventuates are also recommended. Although detrimental to the survival and growth of the introduced P. radiata, the impact of identified forest health risks are not considered to be fatal to the long term success ofP. radiata in this area.展开更多
Due to the late start of China’s forest health industry,related research is lagging behind,which results in the inability to propose a corresponding path to enhance competitiveness.Based on this,the evaluation index ...Due to the late start of China’s forest health industry,related research is lagging behind,which results in the inability to propose a corresponding path to enhance competitiveness.Based on this,the evaluation index system of provincial forest health industry competitiveness was constructed by using the Porter diamond model,and the Entropy-TOPSIS model is used to evaluate the competitiveness of China’s provincial forest health industry,and the key influencing factors of the forest health industry competitiveness are identified by using the grey correlation analysis method,and the specific promotion path was designed.The empirical results show that the grey correlation degree between related and supporting industries and the competitiveness score of the forest health industry is the highest,which confirms that it is the key influencing factor of the competitiveness of the forest health industry.Therefore,government departments should vigorously promote the integration of cultural tourism,medical care,pension and other related industries with the forest health care industry;enterprises should strengthen the construction of forest health infrastr ucture and supporting facilities to improve the level of forest health services.展开更多
The rapid development of visualization techniques makes the demonstration of forestry more profound and free,this study takes Badaling functional area of Beijing Forestry Health Projects as the background,puts forward...The rapid development of visualization techniques makes the demonstration of forestry more profound and free,this study takes Badaling functional area of Beijing Forestry Health Projects as the background,puts forward a practical demonstration thought,and provides references and basis for the future visualized demonstration of such forestry health projects.展开更多
This paper cursorily introduced some ideas and approaches of ecosystem health researches. The definition and connotations of forest ecosystem health have also been expatiated. Defining forest ecosystem health has been...This paper cursorily introduced some ideas and approaches of ecosystem health researches. The definition and connotations of forest ecosystem health have also been expatiated. Defining forest ecosystem health has been discussed from the management objective approach, ecosystem approach, and integration approach. To impel the relative researches in China, more attention on the properties of a forest ecosystem should be paid.展开更多
Forests all over the world have been dramatically impacted by climate change,which has contributed to an increase in the number of pathogen invasions and the rise in the prevalence of forest diseases.This article pres...Forests all over the world have been dramatically impacted by climate change,which has contributed to an increase in the number of pathogen invasions and the rise in the prevalence of forest diseases.This article presents a systematic review that investigates the intricate relationship between climate change and the prevalence of forest diseases.The study identifies climate-related factors that drive the rising incidence of these forest diseases.Following the PRISMA guidelines,73 studies were selected and analyzed from a pool of 3,510 articles,focusing on their spatial and temporal patterns,contextual drivers,and linkages to climate change.The findings underscore the critical role of extended drought periods and rising temperatures as key factors exacerbating forest disease outbreaks.Methodologically,only 3%of the studies utilized field sampling,indicating a predominance of laboratory analysis methods at 45%.Geographically,temperate forests accounted for 78%of the studies,forest plantations 20%,and boreal forests 2%.This review highlights the pressing need for sustainable forest management practices to counteract the adverse impacts of climate change on forest ecosystems.By identifying critical climate drivers and ecological vulnerabilities,this research provides a foundation for adaptive silviculture and pathogen management strategies.展开更多
The evaluation of ecosystem health has become one of the main research topics of ecosystem science, thus more and more assessment methods and frameworks have been put forward in recent years. However, the attention pe...The evaluation of ecosystem health has become one of the main research topics of ecosystem science, thus more and more assessment methods and frameworks have been put forward in recent years. However, the attention people pay to ecosystem health is actually more about what the social functions the ecosystem affords, which depend on the integrity and maintenance of the ecosystem structure and function, and the intensity of disturbance from outside. Accordingly, this research commenced from three main aspects, selected the evaluation indices, and then established the Evaluation Index System of Beijing Forest Ecosystem Health （EIS-BFEH）. In the EIS-BFEH, each of the three foundations contained an easily-operated and standard sub-index system, which compounded the specific natural and social conditions of Beijing and was concrete enough to measure and evaluate. Then with the method of the Analytical Hierarchy Process （AHP）, the comprehensive index （CI） could be obtained, which represented the health of the forest ecosystem. As a case study, the forest ecosystems in the Badaling area were sampled, evaluated, compared and ranked by use of the EIS-BFEH. The result show that the health of natural forests is much better than that of plantations in the Badaling forest center： the average comprehensive index of the former is 7.9, while the latter is only 6.6. From the results, it could also be found that there are nine units in the healthy state, two units in the subhealthy state, and only one unit of Robiniapseudoacacia in the morbid state.展开更多
Forest bathing trip is a short, leisurely visit to forest. In this study we determined the health effects of forest bathing trip on elderly patients with chronic obstructive pulmonary disease （COPD）. The patients we...Forest bathing trip is a short, leisurely visit to forest. In this study we determined the health effects of forest bathing trip on elderly patients with chronic obstructive pulmonary disease （COPD）. The patients were randomly divided into two groups. One group was sent to forest, and the other was sent to an urban area as control. Flow cytometry, ELISA, and profile of mood states （POMS） evaluation were performed. In the forest group,展开更多
This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided...This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.展开更多
As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we disc...As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we discuss the theoretical basis for the selection of particular groups of arthropods as bio-indicators in this paper,and suggest that the evenness and richness of Collembola(Collembolan), Coleoptera(Beetle) and Hymenoptera(Ant) can serve as forest health indicators.In terms of the relationship between forest litter arthropods and forest health,we summarize the main groups of forest litter arthropods suitable as bio-indicators and their ecological functions in forest ecosystems,and subsequently introduce a simple and accurate new method for selecting forest health indicator species by comparing the frequencies of the various species in different habitats.This method was tested with a real case using forest litter arthropods as a bio- indicator to evaluate rain forest health.Finally,the problems in using forest litter arthropods to evaluate and monitor forest habitat health are discussed and the use of multiple bio-indicator species in order to establish a balanced index system is recommended.展开更多
Cork oak forests in Morocco are rich in resources and services thanks to their great biological diversity,playing an important ecological and socioeconomic role.Considerable degradation of the forests has been accentu...Cork oak forests in Morocco are rich in resources and services thanks to their great biological diversity,playing an important ecological and socioeconomic role.Considerable degradation of the forests has been accentuated in recent years by signifi cant human pressure and eff ects of climate change;hence,the health of the stands needs to be monitored.In this study,the Google Engine Earth platform was leveraged to extract the normalized diff erence vegetation index(NDVI)and soil-adjusted vegetation index,from Landsat 8 OLI/TIRS satellite images between 2015 and 2017 to assess the health of the Sibara Forest in Morocco.Our results highlight the importance of interannual variations in NDVI in forest monitoring;the variations had a signifi cantly high relationship(p<0.001)with dieback severity.NDVI was positively and negatively correlated with mean annual precipitation and mean annual temperature with respective coeffi cients of 0.49 and−0.67,highlighting its ability to predict phenotypic changes in forest species.Monthly interannual variation in NDVI between 2016 and 2017 seemed to confi rm fi eld observations of cork oak dieback in 2018,with the largest decreases in NDVI(up to−38%)in December in the most-aff ected plots.Analysis of the infl uence of ecological factors on dieback highlighted the role of substrate as a driver of dieback,with the most severely aff ected plots characterized by granite-granodiorite substrates.展开更多
Forest structure and function are subject to risks of growth declines from intensified drought and frequent extreme events related to climate warming.Knowledge of tree growth declines will help anticipate future respo...Forest structure and function are subject to risks of growth declines from intensified drought and frequent extreme events related to climate warming.Knowledge of tree growth declines will help anticipate future responses of forests to climate change.In this study,we investigated tree growth declines over the last four centuries in a juniper forest on the eastern Tibetan Plateau.By analyzing the radial growth trajectories of individual trees,we identified two events of intense growth decline,one in 1817–1830 and the other in 1969–1999 over the past four centuries.The intensity of the recent decline was unprecedented in the period under study.Ring-width chronology showed a positive correlation with self-calibrating Palmer Drought Severity Indices and a negative correlation with mean monthly temperatures in May and June.The recent intensified growth decline may have been due to temperatureinduced frequent droughts in the study area.Our findings suggest that trees in this juniper forest may face a higher risk of growth decline and even mortality under continued climate warming.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.31971639)National Natural Science Foundation of Fujian Province,China(No.2023J01225)。
文摘The red-edge bands and their derived vegetation indices play a crucial role in monitoring vegetation health.The Gaofen-6(GF-6)and Sentinel-2A satellites are equipped with two and three red-edge bands,respectively,thus making them invaluable for monit-oring forest health.To compare the performance of these two satellites’red-edge bands in monitoring forest health,this study selected forests in Liuyang City,Hunan Province and Tonggu County,Jiangxi Province and Hanzhong City,Shaanxi Province in China as study areas and used three commonly used red-edge indices and the Random Forest(RF)algorithm for the comparison.The three selected red-edge indices were the Normalized Difference Red-Edge Index 1(NDRE1),the Missouri emergency resource information system Ter-restrial Chlorophyll Index(MTCI),and the Inverted Red-Edge Chlorophyll Index(IRECI).Through training of sample regions,this study determined the spectral differences among three forest health levels and established classification criteria for these levels.The res-ults showed that GF-6 imagery provided higher accuracy in distinguishing forest health levels than Sentinel-2A,with an average accur-acy of 90.22%versus 76.55%.This difference is attributed to variations in the wavelengths used to construct the red-edge indices between GF-6 and Sentinel-2A.In the RF algorithm,this study employed three distinct band combinations for classification:all bands including red-edge bands,excluding red-edge bands,and only red-edge bands.The results indicated that GF-6 outperformed Sentinel-2A when using the first and second band combinations,yet slightly underperforming with the third.This outcome was closely associ-ated with the importance of each band’s contribution to classification accuracy reveled by the Gini importance score,their sensitivity in detecting forest health conditions,and the total number of bands employed in the classification process.Overall,the NDRE1 derived from GF-6 achieved the highest average accuracy(90.22%).This study provides a scientific basis for selecting appropriate remote sens-ing data and techniques for forest health monitoring,which is of significant importance for the future ecological protection of forests.
文摘Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley The newly introduced P. radiata are exposed to two kinds of forest health risks： they may be attacked by （a） indigenous pathogens and pests against which they may not possess any resistance or （b） by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical appmach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding conifemus forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are pmvided to improve forest vigour and to reduce the forest health risks posed by indigenous as well as exotic pests and pathogens to the introduced P. radiata. Ways to increase the ability to manage the forest health risks once a particular pest infestation and disease eventuates are also recommended. Although detrimental to the survival and growth of the introduced P. radiata, the impact of identified forest health risks are not considered to be fatal to the long term success ofP. radiata in this area.
基金supported by the Humanities and Social Sciences Fund for Yunnan Provincial Academy and School Education Cooperation(Grant No.SYSX202107)Scientific Research Fund of Yunnan Provincial Department of Education(Grant No.2022Y630)Science and Technology Innovation Fund of Southwest Forestry University(Grant No.KZ21006)。
文摘Due to the late start of China’s forest health industry,related research is lagging behind,which results in the inability to propose a corresponding path to enhance competitiveness.Based on this,the evaluation index system of provincial forest health industry competitiveness was constructed by using the Porter diamond model,and the Entropy-TOPSIS model is used to evaluate the competitiveness of China’s provincial forest health industry,and the key influencing factors of the forest health industry competitiveness are identified by using the grey correlation analysis method,and the specific promotion path was designed.The empirical results show that the grey correlation degree between related and supporting industries and the competitiveness score of the forest health industry is the highest,which confirms that it is the key influencing factor of the competitiveness of the forest health industry.Therefore,government departments should vigorously promote the integration of cultural tourism,medical care,pension and other related industries with the forest health care industry;enterprises should strengthen the construction of forest health infrastr ucture and supporting facilities to improve the level of forest health services.
文摘The rapid development of visualization techniques makes the demonstration of forestry more profound and free,this study takes Badaling functional area of Beijing Forestry Health Projects as the background,puts forward a practical demonstration thought,and provides references and basis for the future visualized demonstration of such forestry health projects.
基金This study was supported by the National Natural Science Foundation of China (30170744) Chinese Academy of Sciences (A grant KZCX2-406) and Changbai Mountain Open Research Station.
文摘This paper cursorily introduced some ideas and approaches of ecosystem health researches. The definition and connotations of forest ecosystem health have also been expatiated. Defining forest ecosystem health has been discussed from the management objective approach, ecosystem approach, and integration approach. To impel the relative researches in China, more attention on the properties of a forest ecosystem should be paid.
基金supported by the UKM research grant no,SK-2022-015the Peninsular Malaysia Forestry Department through the research project titled‘Prediction of Bio-Climatic Habitat Adaptation of Diseases and Pests in Selected Forest Plantation Species in Peninsular Malaysia’,grant No.PHSB-08-2020.
文摘Forests all over the world have been dramatically impacted by climate change,which has contributed to an increase in the number of pathogen invasions and the rise in the prevalence of forest diseases.This article presents a systematic review that investigates the intricate relationship between climate change and the prevalence of forest diseases.The study identifies climate-related factors that drive the rising incidence of these forest diseases.Following the PRISMA guidelines,73 studies were selected and analyzed from a pool of 3,510 articles,focusing on their spatial and temporal patterns,contextual drivers,and linkages to climate change.The findings underscore the critical role of extended drought periods and rising temperatures as key factors exacerbating forest disease outbreaks.Methodologically,only 3%of the studies utilized field sampling,indicating a predominance of laboratory analysis methods at 45%.Geographically,temperate forests accounted for 78%of the studies,forest plantations 20%,and boreal forests 2%.This review highlights the pressing need for sustainable forest management practices to counteract the adverse impacts of climate change on forest ecosystems.By identifying critical climate drivers and ecological vulnerabilities,this research provides a foundation for adaptive silviculture and pathogen management strategies.
文摘The evaluation of ecosystem health has become one of the main research topics of ecosystem science, thus more and more assessment methods and frameworks have been put forward in recent years. However, the attention people pay to ecosystem health is actually more about what the social functions the ecosystem affords, which depend on the integrity and maintenance of the ecosystem structure and function, and the intensity of disturbance from outside. Accordingly, this research commenced from three main aspects, selected the evaluation indices, and then established the Evaluation Index System of Beijing Forest Ecosystem Health （EIS-BFEH）. In the EIS-BFEH, each of the three foundations contained an easily-operated and standard sub-index system, which compounded the specific natural and social conditions of Beijing and was concrete enough to measure and evaluate. Then with the method of the Analytical Hierarchy Process （AHP）, the comprehensive index （CI） could be obtained, which represented the health of the forest ecosystem. As a case study, the forest ecosystems in the Badaling area were sampled, evaluated, compared and ranked by use of the EIS-BFEH. The result show that the health of natural forests is much better than that of plantations in the Badaling forest center： the average comprehensive index of the former is 7.9, while the latter is only 6.6. From the results, it could also be found that there are nine units in the healthy state, two units in the subhealthy state, and only one unit of Robiniapseudoacacia in the morbid state.
基金supported by funds from the National Natural Science Foundation of China(31301139&31201040)funds from Science Technology Department of Zhejiang Province(2012C24005&2014C33130)+2 种基金Health Bureau of Zhejiang Province(11-CX01&2013ZDA002)Zhejiang Provincial Key Disciplinary Fields of Geriatrics Program
文摘Forest bathing trip is a short, leisurely visit to forest. In this study we determined the health effects of forest bathing trip on elderly patients with chronic obstructive pulmonary disease （COPD）. The patients were randomly divided into two groups. One group was sent to forest, and the other was sent to an urban area as control. Flow cytometry, ELISA, and profile of mood states （POMS） evaluation were performed. In the forest group,
文摘This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.
文摘As an important part in forest ecosystems, the arthropod communities in the forest litter are closely related to forest health.Based on the ecological function,community structure and biology of the arthropods,we discuss the theoretical basis for the selection of particular groups of arthropods as bio-indicators in this paper,and suggest that the evenness and richness of Collembola(Collembolan), Coleoptera(Beetle) and Hymenoptera(Ant) can serve as forest health indicators.In terms of the relationship between forest litter arthropods and forest health,we summarize the main groups of forest litter arthropods suitable as bio-indicators and their ecological functions in forest ecosystems,and subsequently introduce a simple and accurate new method for selecting forest health indicator species by comparing the frequencies of the various species in different habitats.This method was tested with a real case using forest litter arthropods as a bio- indicator to evaluate rain forest health.Finally,the problems in using forest litter arthropods to evaluate and monitor forest habitat health are discussed and the use of multiple bio-indicator species in order to establish a balanced index system is recommended.
文摘Cork oak forests in Morocco are rich in resources and services thanks to their great biological diversity,playing an important ecological and socioeconomic role.Considerable degradation of the forests has been accentuated in recent years by signifi cant human pressure and eff ects of climate change;hence,the health of the stands needs to be monitored.In this study,the Google Engine Earth platform was leveraged to extract the normalized diff erence vegetation index(NDVI)and soil-adjusted vegetation index,from Landsat 8 OLI/TIRS satellite images between 2015 and 2017 to assess the health of the Sibara Forest in Morocco.Our results highlight the importance of interannual variations in NDVI in forest monitoring;the variations had a signifi cantly high relationship(p<0.001)with dieback severity.NDVI was positively and negatively correlated with mean annual precipitation and mean annual temperature with respective coeffi cients of 0.49 and−0.67,highlighting its ability to predict phenotypic changes in forest species.Monthly interannual variation in NDVI between 2016 and 2017 seemed to confi rm fi eld observations of cork oak dieback in 2018,with the largest decreases in NDVI(up to−38%)in December in the most-aff ected plots.Analysis of the infl uence of ecological factors on dieback highlighted the role of substrate as a driver of dieback,with the most severely aff ected plots characterized by granite-granodiorite substrates.
基金financially supported by the National Natural Science Foundation of China project(No.31330015)
文摘Forest structure and function are subject to risks of growth declines from intensified drought and frequent extreme events related to climate warming.Knowledge of tree growth declines will help anticipate future responses of forests to climate change.In this study,we investigated tree growth declines over the last four centuries in a juniper forest on the eastern Tibetan Plateau.By analyzing the radial growth trajectories of individual trees,we identified two events of intense growth decline,one in 1817–1830 and the other in 1969–1999 over the past four centuries.The intensity of the recent decline was unprecedented in the period under study.Ring-width chronology showed a positive correlation with self-calibrating Palmer Drought Severity Indices and a negative correlation with mean monthly temperatures in May and June.The recent intensified growth decline may have been due to temperatureinduced frequent droughts in the study area.Our findings suggest that trees in this juniper forest may face a higher risk of growth decline and even mortality under continued climate warming.
