在城市规模不断扩张的过程中,北京市自然保护区植物群落正面临着前所未有的干扰胁迫。研究植物群落对干扰的抵抗力具有理论和实践意义。在北京市松山和喇叭沟门两个自然保护区植物群落中调查了22个样地,记录到213种植物,测度了33个植物...在城市规模不断扩张的过程中,北京市自然保护区植物群落正面临着前所未有的干扰胁迫。研究植物群落对干扰的抵抗力具有理论和实践意义。在北京市松山和喇叭沟门两个自然保护区植物群落中调查了22个样地,记录到213种植物,测度了33个植物功能性状。在集成前人成果的基础上,量化了每个性状在基建工程、放牧或旅游践踏、火烧以及外来种入侵干扰下的功能属性;计算了物种、功能群和群落尺度上的功能指数;利用回归分析方法描绘了物种丰富度与功能指数间的关系。结果表明:(1)植被恢复力指数(plant restoration index)在4.36-10.15之间,草本植物大于木本植物;物种对不同干扰的抵抗力功能指数(resistance index to disturbance)变化范围分别为:放牧10.27-23.15,乔木和灌木大于其他生长型植物;火烧9.01-22.15,乔木大于灌木,后者又大于草本;外来种入侵4.41-10.54,乔木大于其他生长型。(2)以山杨(Populus davidiana)为优势种的群丛,其植被恢复力以及对干扰的抵抗力较其他群丛强。(3)在乔木层和草本层,物种丰富度与功能指数不相关;在灌木层,物种丰富度与放牧、火烧和外来种入侵的功能指数正相关,与植被恢复指数不相关。作者建立了研究区域物种、功能群和群落尺度上的植被功能指数数据库,为自然保护区植被结构调整和恢复提供了技术支撑。群落尺度的功能值取决于优势种的功能值,物种多样性是生态系统功能维持的重要基础。物种的功能冗余可能与植物群落结构层次以及干扰类型有关。本文结果为生态系统物种功能冗余假说提供了一个例证。展开更多
Crown fire damage is a mixture of three principal fire-related components:charred material,scorched foliage,and unaltered green canopy.This study estimated the abundance of these physical alterations in two immediate ...Crown fire damage is a mixture of three principal fire-related components:charred material,scorched foliage,and unaltered green canopy.This study estimated the abundance of these physical alterations in two immediate post-fire Mediterranean forest contexts(Portugal and Italy)by applying linear spectral mixture analysis(LSMA)on Sentinel-2 imagery.The tree crowns fire damage was subsequently mapped,integrating fractional abundance information in a random forest(RF)algorithm,comparing the accuracy resulting from the adoption of generic or image spectral libraries as the primary investigative goal.Although image-derived endmembers resulted in more effectiveness in terms of fire-related components abundance quantification(LMSAderived RMSE<0.1),the F-scores always were≥90%whether generic endmembers or image endmembers derived information was employed.The environmental heterogeneity of the two study areas affected the fire severity gradients,with a prevalence of the charred(PT)(45–46%)and green class(IT)(44–53%).Post-fire temporal monitoring was initialized by applying the proposed strategies,and the preliminary results showed a positive recovery trend in forest vegetation from the first year following the fire event,with a reduced charcoal predominance and an increasing proportion of green components.展开更多
Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental changes.As an important ecological factor,the occurrence of fire is affected by vegetation cover,...Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental changes.As an important ecological factor,the occurrence of fire is affected by vegetation cover,and fire can feed back into both vegetation and climatic change.The causes of fire events are diverse;and can include volcanic eruptions.The amount of charcoal in sediment sequences is related to the frequency and intensity of fire,and hence under good preservation conditions fire history can be reconstructed from fossil charcoal abundance.Until now,little research on the role of fire has been carried out in northeastern China.In this study,through research on charcoal and tephra shards from Gushantun and Hanlongwan,Holocene vegetation change in relation to fire and volcanic events in Jilin,Northeastern China,was investigated.Where tephra shards are present in Gushantun it is associated with low level of both conifers and broadleaved trees,and is also associated with a pronounced charcoal peak.This suggests forest cover was greatly reduced from a fire caused by an eruption of the Tianchi volcano.We also detected one tephra layer in Hanlongwan,which also has the almost same depth with low level forest pollen values and one charcoal peak.This was caused probably by an eruption of the Jinlongdingzi volcano.展开更多
We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected ...We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected areas during pre and post-fire seasons, （2） to evaluate vegetation struc- ture and diversity by layer in the four fire frequency zones, （3） to evalu- ate the impact of fire frequency on the structure of economically impor- tant tree species of the region, and （4） to quantify fuel loads by fire fre- quency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low- frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class （A） and saplings of size class （B）, represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sis- soo after fire, whereas intermediate-aged trees were more abundant pre- fire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The netchange in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, how- ever, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest manage- ment. Use of c展开更多
In central eastern Korea, there has been a continued effort to sustain pine forests because of their value for wood and mushroom production, as well as for other resources. Through the analysis of previously burned ar...In central eastern Korea, there has been a continued effort to sustain pine forests because of their value for wood and mushroom production, as well as for other resources. Through the analysis of previously burned areas,we clarified the effects of fire on vegetation dynamics of pine forests by measuring changes in species composition,population structure, and the growth rates of major tree species. Vegetation analysis was conducted on a series of 100 m^2 plots established in Korean red pine(Pinus densiflora Siebold. & Zucc.) and Mongolian oak(Quercus mongolica Fisch. Ex Ledeb.) forests situated in three different topographic positions on slopes where fire severity varied. We confirmed that most pine trees will succumb to even a surface fire, whereas oak may be killed following high intensity or infrequent fires but will sprout and become dominant. Complete protection from fire favors other, more shade-tolerant deciduous hardwoods. Different restoration plans apply, based on observed vegetation responses for each topographic zone. Near the ridge top,where pine seed sources are most limited, it may be necessary to restore pine forests by planting and to control competing shrubs and herbs. At the mountain foot, where exotic species and species modified by hybridization have invaded aggressively, restoration that involves the introduction of natural vegetation is required. Mid-slope sites,where pine has been replaced by natural vegetation dominated by Mongolian oak, do not require any form of restorative treatment.展开更多
The forest resource of Heilongjiang province has important position in china. On the basis of the six times of national forest inventory data （1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003） survey...The forest resource of Heilongjiang province has important position in china. On the basis of the six times of national forest inventory data （1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003） surveyed by the Forestry Ministry of P. R. China from 1973 to 2003, the carbon storage of forests in Heilongjiang Province are estimated by using the method of linear relationship of each tree species between biomass and volume. The results show that the carbon storage of Heilongjiang forests in the six periods （1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003） are 7.164×10^8 t, 4.871×10^8 t, 5.094×10^8 t, 5.292×10^8 t, 5.594×10^8 t and 5.410×10^8 t, respectively., which showed a trend of decreasing in early time and then increasing. It indicated that Heilongjiang forests play an important role as a sink of atmospheric carbon dioxide during past 30 years. Based on the data of forest fires from 1980 to 1999 and ground biomass estimation for some forest types in Heilongjiang Province, it is estimated that the amount of mean annual consumed biomass of forests is 391758.65t-522344.95t, accounting for 6.4%-8.4% of total national consummation from forest fires, and the amount of carbon emission is 176 291.39t-235 055.23t, about 8% of total national emission from forest fires. The emission of CO2, CO, CH4 and NMHC from forest fires in Heilongjiang Province are estimated at 581761.6-775682.25 t, 34892.275-46523.04 t, 14091.11-18788.15 t and 6500-9000 t, respectively, every year.展开更多
文摘在城市规模不断扩张的过程中,北京市自然保护区植物群落正面临着前所未有的干扰胁迫。研究植物群落对干扰的抵抗力具有理论和实践意义。在北京市松山和喇叭沟门两个自然保护区植物群落中调查了22个样地,记录到213种植物,测度了33个植物功能性状。在集成前人成果的基础上,量化了每个性状在基建工程、放牧或旅游践踏、火烧以及外来种入侵干扰下的功能属性;计算了物种、功能群和群落尺度上的功能指数;利用回归分析方法描绘了物种丰富度与功能指数间的关系。结果表明:(1)植被恢复力指数(plant restoration index)在4.36-10.15之间,草本植物大于木本植物;物种对不同干扰的抵抗力功能指数(resistance index to disturbance)变化范围分别为:放牧10.27-23.15,乔木和灌木大于其他生长型植物;火烧9.01-22.15,乔木大于灌木,后者又大于草本;外来种入侵4.41-10.54,乔木大于其他生长型。(2)以山杨(Populus davidiana)为优势种的群丛,其植被恢复力以及对干扰的抵抗力较其他群丛强。(3)在乔木层和草本层,物种丰富度与功能指数不相关;在灌木层,物种丰富度与放牧、火烧和外来种入侵的功能指数正相关,与植被恢复指数不相关。作者建立了研究区域物种、功能群和群落尺度上的植被功能指数数据库,为自然保护区植被结构调整和恢复提供了技术支撑。群落尺度的功能值取决于优势种的功能值,物种多样性是生态系统功能维持的重要基础。物种的功能冗余可能与植物群落结构层次以及干扰类型有关。本文结果为生态系统物种功能冗余假说提供了一个例证。
基金funded by the European Commission and the Regione Calabria with the POR Calabria FESR FSE 2014-2020source[CUP C39B18000070002]Joao M.N.Silva was funded by the Forest Research Centre,a research unit funded by Fundacao para a Ciência e a Tecnologia IP(FCT),Portugal(UIDB/00239/2020)by the project FireCast–Forecasting fire probability and characteristics for a habitable pyro environment,funded by FCT(PCIF/GRF/0204/2017).
文摘Crown fire damage is a mixture of three principal fire-related components:charred material,scorched foliage,and unaltered green canopy.This study estimated the abundance of these physical alterations in two immediate post-fire Mediterranean forest contexts(Portugal and Italy)by applying linear spectral mixture analysis(LSMA)on Sentinel-2 imagery.The tree crowns fire damage was subsequently mapped,integrating fractional abundance information in a random forest(RF)algorithm,comparing the accuracy resulting from the adoption of generic or image spectral libraries as the primary investigative goal.Although image-derived endmembers resulted in more effectiveness in terms of fire-related components abundance quantification(LMSAderived RMSE<0.1),the F-scores always were≥90%whether generic endmembers or image endmembers derived information was employed.The environmental heterogeneity of the two study areas affected the fire severity gradients,with a prevalence of the charred(PT)(45–46%)and green class(IT)(44–53%).Post-fire temporal monitoring was initialized by applying the proposed strategies,and the preliminary results showed a positive recovery trend in forest vegetation from the first year following the fire event,with a reduced charcoal predominance and an increasing proportion of green components.
基金supported by the National Natural Science Foundation of China (Grant No. 41202260)the Chinese Academy of Sciences Strategic Priority Research Program (Grant No. XDA01020304)Overseas Research Scholarship (UK, 2007–2010)
文摘Volatiles erupted from large-scale explosive volcanic activities have a significant impact on climate and environmental changes.As an important ecological factor,the occurrence of fire is affected by vegetation cover,and fire can feed back into both vegetation and climatic change.The causes of fire events are diverse;and can include volcanic eruptions.The amount of charcoal in sediment sequences is related to the frequency and intensity of fire,and hence under good preservation conditions fire history can be reconstructed from fossil charcoal abundance.Until now,little research on the role of fire has been carried out in northeastern China.In this study,through research on charcoal and tephra shards from Gushantun and Hanlongwan,Holocene vegetation change in relation to fire and volcanic events in Jilin,Northeastern China,was investigated.Where tephra shards are present in Gushantun it is associated with low level of both conifers and broadleaved trees,and is also associated with a pronounced charcoal peak.This suggests forest cover was greatly reduced from a fire caused by an eruption of the Tianchi volcano.We also detected one tephra layer in Hanlongwan,which also has the almost same depth with low level forest pollen values and one charcoal peak.This was caused probably by an eruption of the Jinlongdingzi volcano.
基金financed by NRSA,Hyderabad,Forest Department of Chhattisgarh,India
文摘We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected areas during pre and post-fire seasons, （2） to evaluate vegetation struc- ture and diversity by layer in the four fire frequency zones, （3） to evalu- ate the impact of fire frequency on the structure of economically impor- tant tree species of the region, and （4） to quantify fuel loads by fire fre- quency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low- frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class （A） and saplings of size class （B）, represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sis- soo after fire, whereas intermediate-aged trees were more abundant pre- fire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The netchange in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, how- ever, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest manage- ment. Use of c
基金supported by a research grant from Seoul Women’s University(2018)
文摘In central eastern Korea, there has been a continued effort to sustain pine forests because of their value for wood and mushroom production, as well as for other resources. Through the analysis of previously burned areas,we clarified the effects of fire on vegetation dynamics of pine forests by measuring changes in species composition,population structure, and the growth rates of major tree species. Vegetation analysis was conducted on a series of 100 m^2 plots established in Korean red pine(Pinus densiflora Siebold. & Zucc.) and Mongolian oak(Quercus mongolica Fisch. Ex Ledeb.) forests situated in three different topographic positions on slopes where fire severity varied. We confirmed that most pine trees will succumb to even a surface fire, whereas oak may be killed following high intensity or infrequent fires but will sprout and become dominant. Complete protection from fire favors other, more shade-tolerant deciduous hardwoods. Different restoration plans apply, based on observed vegetation responses for each topographic zone. Near the ridge top,where pine seed sources are most limited, it may be necessary to restore pine forests by planting and to control competing shrubs and herbs. At the mountain foot, where exotic species and species modified by hybridization have invaded aggressively, restoration that involves the introduction of natural vegetation is required. Mid-slope sites,where pine has been replaced by natural vegetation dominated by Mongolian oak, do not require any form of restorative treatment.
基金This study was supported by National Natural Sci-ence Foundation of China (No.30471404)National Doctoral Subject Fund of China (No.20040225003)+1 种基金Natural Science Fund of Heilongjiang Province (ZJD04-0102)Research Program of Science and Tech-nology of Heilongjiang Province (GB05B602)
文摘The forest resource of Heilongjiang province has important position in china. On the basis of the six times of national forest inventory data （1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003） surveyed by the Forestry Ministry of P. R. China from 1973 to 2003, the carbon storage of forests in Heilongjiang Province are estimated by using the method of linear relationship of each tree species between biomass and volume. The results show that the carbon storage of Heilongjiang forests in the six periods （1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003） are 7.164×10^8 t, 4.871×10^8 t, 5.094×10^8 t, 5.292×10^8 t, 5.594×10^8 t and 5.410×10^8 t, respectively., which showed a trend of decreasing in early time and then increasing. It indicated that Heilongjiang forests play an important role as a sink of atmospheric carbon dioxide during past 30 years. Based on the data of forest fires from 1980 to 1999 and ground biomass estimation for some forest types in Heilongjiang Province, it is estimated that the amount of mean annual consumed biomass of forests is 391758.65t-522344.95t, accounting for 6.4%-8.4% of total national consummation from forest fires, and the amount of carbon emission is 176 291.39t-235 055.23t, about 8% of total national emission from forest fires. The emission of CO2, CO, CH4 and NMHC from forest fires in Heilongjiang Province are estimated at 581761.6-775682.25 t, 34892.275-46523.04 t, 14091.11-18788.15 t and 6500-9000 t, respectively, every year.
