Understanding local variation in forest biomass allows for a better evaluation of broad-scale patterns and interpretation of forest ecosystems’role in carbon dynamics.This study focuses on patterns of aboveground tre...Understanding local variation in forest biomass allows for a better evaluation of broad-scale patterns and interpretation of forest ecosystems’role in carbon dynamics.This study focuses on patterns of aboveground tree biomass within a fully censused 20 ha forest plot in a temperate forest of northern Alabama,USA.We evaluated the relationship between biomass and topography using ridge and valley landforms along with digitally derived moisture and solar radiation indices.Every live woody stem over 1 cm diameter at breast height within this plot was mapped,measured,and identified to species in 2019-2022,and diameter data were used along with speciesspecific wood density to map the aboveground biomass at the scale of 20 m×20 m quadrats.The aboveground tree biomass was 211 Mg·ha^(-1).Other than small stream areas that experienced recent natural disturbances,the total stand biomass was not associated with landform or topographic indices.Dominant species,in contrast,had strong associations with topography.American beech(Fagus grandifolia)and yellow-poplar(Liriodendron tulipfera)dominated the valley landform,with 37% and 54% greater biomass in the valley than their plot average,respectively.Three other dominant species,white oak(Quercus alba),southern shagbark hickory(Carya carolinaeseptentrionalis),and white ash(Fraxinus americana),were more abundant on slopes and benches,thus partitioning the site.Of the six dominant species,only sugar maple(Acer saccharum)was not associated with landform.Moreover,both topographic wetness and potential radiation indices were significant predictors of dominant species biomass within each of the landforms.The study highlights the need to consider species when examining forest productivity in a range of site conditions.展开更多
Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-cano...Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.展开更多
Haemosporidian parasites are widespread among birds globally,with impacts ranging from severe disease to negligible effects,particularly in host species that have coevolved with their parasites.Despite their ecologica...Haemosporidian parasites are widespread among birds globally,with impacts ranging from severe disease to negligible effects,particularly in host species that have coevolved with their parasites.Despite their ecological importance,the divereity and prevalence of these parasites in the Afrotropical region remain poorly understood,especially in urban environments.Our study investigated the prevalence and diversity of haemosporidian parasites in Afrotropical avian hosts,focusing on differences between urban and non-urban habitats.We screened 95birds from various species in Nigeria and investigated whether urbanization is associated with chan ges in the prevalence and richness of lineages of three haemosporidian parasites(Haemoproteus,Plasmodium,and Leucocytozoon).We found a haemosporidian prevalence of 36.8%with genus-specific differences between urban and non-urban habitats.The probability of Haemoproteus infection was higher in urban than non-urban habitats,but Plasmodium and Leucocytozoon did not differ between these habitats.Moreover,Haemoproteus lineages were exclusively found in urban habitats,while most Plasmodium lineages were restricted to non-urban habitats.Notably,we expanded the knowledge on diversity of haemosporidian lineages and avian hosts in the Afrotropics,with the first-ever record of hPYNJOC1 and pLUME2 lineages for the region,and the addition of new hosts for four Haemoproteus and two Plasmodium lineages.Our findings highlight the complexity of host-parasite relationships and the need for further research into the dynamics of haemosporidian parasites in Afrotropical avian hosts inhabiting diverse habitats.Overall,our study contributes to a better understanding of the prevalence,diversity,and distribution of haemosporidian parasites in the Afrotropics,emphasizing the importance of continued surveillance and monitoring to inform strategies for avian conservation and management.展开更多
We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial...We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial photographic comparisons to the current forest typology generated from airborne Li DAR data, and we examined the role of past natural disturbance on the current spatial distribution of forest structural types.We found six forest structural types in the landscape: early regeneration(T1 and T2), young even-aged stands(T3), uneven-aged stands(T4) and adult stands(T5and T6).All of the types were related to the timing and severity of past storms, with early-regeneration structures being found in areas markedly affected in recent times, and adult stands predominating in those areas that had suffered lowest damage levels within the study period.In general, landscapes where high or medium levels of damage were recurrent also presented higher levels of spatial heterogeneity,whereas the opposite pattern was found in the less markedly affected landscape, characterized by thepresence of large regular patches.Our results show the critical role that storm regimes in terms of timing and severity of past storms can play in shaping current forest structure and future dynamics in subalpine forests.The knowledge gained could be used to help define alternative forest management strategies oriented toward the enhancement of landscape heterogeneity as a measure to face future environmental uncertainty.展开更多
Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production i...Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.展开更多
This study used the dynamic headspace adsorption(DHS) to collect volatile organic compounds(VOCs) released from the Fokienia hodginsii forest in summer, and analyzed the the composition and concentration of VOCs and t...This study used the dynamic headspace adsorption(DHS) to collect volatile organic compounds(VOCs) released from the Fokienia hodginsii forest in summer, and analyzed the the composition and concentration of VOCs and their correlation with environmental factors. The results showed that: there were 165 types of VOCs in the Fokienia hodginsii forest;the diurnal variation of the concentration of total volatile organic compounds(TVOCs) was "W"-shaped, the concentration reached its peak at 13:00–15:00 and its trough at 1:00–3:00;VOCs beneficial to human health mainly appeared at 13:00, while VOCs harmful to human health chiefly occurred at 11:00–19:00. The correlation analysis between the concentration of VOCs and climatic factors indicated that the concentration of VOCs was basically proportional to the temperature and illumination intensity and inversely proportional to the humidity and wind speed. In other words, the diurnal variation of the concentration was consistent with the diurnal variation of temperature and illumination intensity.展开更多
positively or negatively depending on the condition.Vegetation has influence on the soil physico-chemical characteristics.Land use land cover changes are the main factors in the process of land resource degradation.Th...positively or negatively depending on the condition.Vegetation has influence on the soil physico-chemical characteristics.Land use land cover changes are the main factors in the process of land resource degradation.The objectives of this study were to define the soil texture,bulk density and extent of organic carbon in church forests and adjacent croplands and to compare the values.Transect lines of 100 meter apart and plots of 20 m×20 m were established to collect soil samples in the church forests and individual farm plots.The distance between plots was 100 m.Horizon based soil sampling was undertaken.Soil samples were collected on a diagonal position from 2 edges and the center from 2 soil horizons(H1 and H2)for soil texture and soil organic carbon(SOC)analysis.For bulk density(BD)soil core samplers were used.The data was analyzed using one way ANOVA in SPSS v20.Mean separation was undertaken by least significance difference.The results revealed the%clay content was significantly higher in croplands than church forests and the%sand was higher in church forests than croplands at(p<0.05).The SOC was significantly higher in H1 than H2 and in church forests than croplands at(p<0.05).The better soil characteristics were obtained in church forests than in croplands.Hence,it is recommended to conserve the natural forests as in the church forests to maintain better property of the soil through enhancing soil organic matter,soil organic carbon and by decreasing soil bulk density.展开更多
Background： Growth and yield models are important tools for forest planning. Due to its geographic location, topology, and history of management, the forests of the Adirondacks Region of New York are unique and compl...Background： Growth and yield models are important tools for forest planning. Due to its geographic location, topology, and history of management, the forests of the Adirondacks Region of New York are unique and complex. However, only a relatively limited number of growth and yield models have been developed and/or can be reasonably extended to this region currently. Methods： in this analysis, 571 long-term continuous forest inventory plots with a total of 10 - 52 years of measurement data from four experimental forests maintained by the State University of New York College of Environmental Science and Forestry and one nonindustrial private forest were used to develop an individual tree growth model for the primary hardwood and softwood species in the region. Species-specific annualized static and dynamic equations were developed using the available data and the system was evaluated for long-term behavior. Results： Equivalence tests indicated that the Northeast Variant of the Forest Vegetation Simulator （FVS-NE） was biased in its estimation of tree total and bole height, diameter and height increment, and mortality for most species examined. In contrast, the developed static and annualized dynamic, species-specific equations performed quite well given the underlying variability in the data. Long-term model projections were consistent with the data and suggest a relatively robust system for prediction. Conclusions： Overall, the developed growth model showed reasonable behavior and is a significant improvement over existing models for the region. The model also highlighted the complexities of forest dynamics in the region and should help improve forest planning efforts there.展开更多
Innovation in forestry education is needed to address changing contexts of the positionality of forests.This is particularly signifi cant in the Asia–Pacifi c region,where deforestation and degradation are high.Howev...Innovation in forestry education is needed to address changing contexts of the positionality of forests.This is particularly signifi cant in the Asia–Pacifi c region,where deforestation and degradation are high.However,the accessibility of high-quality forestry education to address changing regional and global contexts is lacking.A series of innovative sustainable forest management(SFM)open education resource(OER)courses were developed and implemented to improve the accessibility of SFM education to enhance teaching quality,curriculum,and research capacity of universities in the Asia-Pacifi c Region.To evaluate the SFM-OER program in terms of student experiences,this study investigated student achievement,perceived success of the pedagogical approach and instructional design,and perceived eff ectiveness of the learning activities in promoting active and transformative learning through the assessment of a 1,191-course feedback survey between 2018 and 2020,including the global pandemic.This study revealed that the program attracted diverse student demographics,including a higher proportion of female students majoring in forestry,ecology,and other environmental studies.Their primary motivation to participate in the courses was to gain international experience,followed by the fl exibility of online learning,mandatory course requirements,and earning course credits.Students were satisfi ed with the Canvas learning management system.Most students spent less than 5 to 10 h of their weekly time in the course and agreed or strongly agreed that the workloads were manageable.Students refl ected positively on various learning activities and assignments,such as watching lecture videos,taking quizzes,reading and summarizing,having discussions,and peer review writing.However,they did not clearly prefer specifi c learning activities,signifying the importance of using diverse learning activities to satisfy diverse individual learning styles in online settings.This analysis contributes to the further development of student-centered pedagogical development for online learning and provides insight into the ways forward for online higher forestry education,while repurposing existing OER courses in a post-Covid-19 era.展开更多
The effect of litter on forest regeneration depends on the characteristics of regional climate and also shows community specificity. The influences of plant litter on seed germination and seedling growth of Larch Sibe...The effect of litter on forest regeneration depends on the characteristics of regional climate and also shows community specificity. The influences of plant litter on seed germination and seedling growth of Larch Siberian forest in the Altai Mountains were investigated through two simulated experiments including litter coverage and litter aqueous extracts. In the litter coverage experiment, three litter coverage methods including above (D), below (S) and in the middle (Z) of litter were set with the litter coverage thickness of 0, 1, 2, and 4 cm, while two aqueous extract obtained methods using the air-dried litter and litter ash after fir were used with the concentration of 10%, 40%, 80% and 100% in the present study. Results showed that: the aqueous extracts obtained using the air-dried litter restrained the seed germination, while the aqueous extracts obtained using litter ash improved the seed germination. Compared with other litter concentration, the influences of 100% concentration reach highest. The seed germination rate, seed germination potential and vital index under the treatment of seeds above the litter coverage were highest, which were significantly higher than other treatments. The above-ground biomass was significantly higher and the inhibition index of below-ground bio-mass was significantly lower under the treatment of seed above the litter with thin litter cover-age (S1) compared to other litter coverage treatments. These results indicated that the litter aqueous extract and the litter coverage had a combined effect on the seed germination and seedling growth of Siberian larch forest. Fire disturbance could promote seed germination by modifying the adverse effects of litter aqueous extracts and litter coverage, and thus plays an important role in the regeneration of Siberian larch in the Altai Mountains.展开更多
With the Fokienia hodginsii forest in Qishan National Forest Park as the object of study, this study observed the diurnal variation of concentrations of atmospheric aerosol particles inside and outside the forest, col...With the Fokienia hodginsii forest in Qishan National Forest Park as the object of study, this study observed the diurnal variation of concentrations of atmospheric aerosol particles inside and outside the forest, collected the data of microclimate factors, and analyzed their correlation with the particle concentration. The results showed that the diurnal variation curves of the particle concentration of the forest and the forest edge had two peaks and two troughs". There were two peaks throughout the day at 13:00 and 19:00 or 17:00 as well as two troughs at 7:00-9:00 and 15:00 or 17:00. The atmospheric aerosol particle in the forest was mainly fine particles, while the forest edge was dominated by coarse particles. For the forest and the forest edge, the diurnal variation trends of various atmospheric aerosol particles were similar. The particle concentration was positively correlated with temperature, relative humidity, and il umination intensity and negatively correlated with wind speed, and the particle concentration outside the forest was significantly negatively correlated with the wind speed.展开更多
This study analyzed the microclimate factors and human comfort index of the inner and outer Fokienia hodginsii forests and of a city square.The results showed that:①In terms of the average daily temperature,the inner...This study analyzed the microclimate factors and human comfort index of the inner and outer Fokienia hodginsii forests and of a city square.The results showed that:①In terms of the average daily temperature,the inner and outer forests and the city square ranked as follows:square>outer forest>inner forest.The temperature of the inner forest was 8.21–11.73℃lower than that of the city square,and the temperature of the outer forest was 7.41–10.34℃lower than that of the city square.The inner forest was cooled by 24.21%and 1.37%respectively than the outer forest and the city square.②In terms of the average daily relative humidity,the inner and outer forests and the city square ranked as follows:square<outer forest<inner forest.The average daily relative humidity of the inner forest,the outer forest,and the city square was 68.57,84.91,and 88.27,respectively.③In terms of the average daily wind speed,the inner and outer forests and the city square ranked as:square>outer forest>inner forest.Their daily variation ranges were 0–0.75,0.18–0.43,and 0.12–0.31 m/s,respectively.④In terms of the daily average illumination intensity,the inner and outer forests and the square ranked as:square>outer forest>inner forest.Their average daily illumination intensities were 371.68,4,582.01,and 17,641.63 lux,respectively.展开更多
Forestry plays an important role in maintaining the balance of the ecological environment and improving people's quality of life. It can also promote the development of related industries. At present, significant ...Forestry plays an important role in maintaining the balance of the ecological environment and improving people's quality of life. It can also promote the development of related industries. At present, significant achievements have been made in forestry development, but the current situation of forest resources management is not optimistic and there are some deficiencies. This paper focuses on the management of forest resources, based on the analysis of potential problems, puts forward targeted improvement strategies to provide reference for related research.展开更多
基金supported in part by the intramural research program of the US Department of Agriculture,National Institute of Food and Agriculture,Evans-Allen#1024525,and Capacity Building Grant#006531supported in part by the US National Science Foundation RII Track 2 FEC:Leveraging Intelligent Informatics and Smart Data for Improved Understanding of Northern Forest Ecosystem Resiliency(INSPIRES)#1920908by The Lyndhurst Foundation.
文摘Understanding local variation in forest biomass allows for a better evaluation of broad-scale patterns and interpretation of forest ecosystems’role in carbon dynamics.This study focuses on patterns of aboveground tree biomass within a fully censused 20 ha forest plot in a temperate forest of northern Alabama,USA.We evaluated the relationship between biomass and topography using ridge and valley landforms along with digitally derived moisture and solar radiation indices.Every live woody stem over 1 cm diameter at breast height within this plot was mapped,measured,and identified to species in 2019-2022,and diameter data were used along with speciesspecific wood density to map the aboveground biomass at the scale of 20 m×20 m quadrats.The aboveground tree biomass was 211 Mg·ha^(-1).Other than small stream areas that experienced recent natural disturbances,the total stand biomass was not associated with landform or topographic indices.Dominant species,in contrast,had strong associations with topography.American beech(Fagus grandifolia)and yellow-poplar(Liriodendron tulipfera)dominated the valley landform,with 37% and 54% greater biomass in the valley than their plot average,respectively.Three other dominant species,white oak(Quercus alba),southern shagbark hickory(Carya carolinaeseptentrionalis),and white ash(Fraxinus americana),were more abundant on slopes and benches,thus partitioning the site.Of the six dominant species,only sugar maple(Acer saccharum)was not associated with landform.Moreover,both topographic wetness and potential radiation indices were significant predictors of dominant species biomass within each of the landforms.The study highlights the need to consider species when examining forest productivity in a range of site conditions.
基金supported by the MITACS Accelerate grant with Greenfirst,industry partner in La Sarre,QC,Canada.
文摘Fire disturbances are increasing under global climate change and ecological transformations of forests are occurring.Specifically,shifts from productive closed-canopy feather moss forests to low-productivity open-canopy lichen(Cladonia spp.)woodlands have been observed in boreal forests of eastern Canada.It has been hypothesized that high severity of fires would be the cause of this change,but this is difficult to validate a posteriori on mature forest stands.Because charcoal properties are affected by fire severity,we have put forward the hypothesis that the amount and physicochemical properties of charcoal(C,N,H,O,ash,surface area)would be different and indicative of a greater fire severity for open-canopy forests compared to closed canopy ones.Our hypothesis was partly validated in that the amount of charcoal found on the ground of closed-canopy forests was greater than that of open-canopy forests.However,the physicochemical properties were not different,albeit a greater variability of charcoal properties for open canopy stands.These results do not allow us to fully validate or reject our hypothesis on the role of fire severity in the shift between open and closed canopy stands.However,they suggest that the variability in fire conditions as well as the amounts of charcoal produced are different between the two ecosystem types.Furthermore,considering the role that biochar may play in improving soil conditions and promoting vegetation restoration,our results suggest that charcoal may play a role in maintaining these two stable alternative ecosystem states.
基金APLORI Foundations funded this study as part of the Ph D project awarded to A.G.Awoyemifunded by the Spanish Ministry of Science and Innovation(PID2019-107423GA-I00/SRA+1 种基金State Research Agency/10.13039/501100011033)supported by a postdoctoral contract from the University of Granada(‘Contrato Puente’UGR)。
文摘Haemosporidian parasites are widespread among birds globally,with impacts ranging from severe disease to negligible effects,particularly in host species that have coevolved with their parasites.Despite their ecological importance,the divereity and prevalence of these parasites in the Afrotropical region remain poorly understood,especially in urban environments.Our study investigated the prevalence and diversity of haemosporidian parasites in Afrotropical avian hosts,focusing on differences between urban and non-urban habitats.We screened 95birds from various species in Nigeria and investigated whether urbanization is associated with chan ges in the prevalence and richness of lineages of three haemosporidian parasites(Haemoproteus,Plasmodium,and Leucocytozoon).We found a haemosporidian prevalence of 36.8%with genus-specific differences between urban and non-urban habitats.The probability of Haemoproteus infection was higher in urban than non-urban habitats,but Plasmodium and Leucocytozoon did not differ between these habitats.Moreover,Haemoproteus lineages were exclusively found in urban habitats,while most Plasmodium lineages were restricted to non-urban habitats.Notably,we expanded the knowledge on diversity of haemosporidian lineages and avian hosts in the Afrotropics,with the first-ever record of hPYNJOC1 and pLUME2 lineages for the region,and the addition of new hosts for four Haemoproteus and two Plasmodium lineages.Our findings highlight the complexity of host-parasite relationships and the need for further research into the dynamics of haemosporidian parasites in Afrotropical avian hosts inhabiting diverse habitats.Overall,our study contributes to a better understanding of the prevalence,diversity,and distribution of haemosporidian parasites in the Afrotropics,emphasizing the importance of continued surveillance and monitoring to inform strategies for avian conservation and management.
基金Financial support for this study was provided by the Spanish Ministry of Economy and Competitiveness through the project RESILFOR(AGL2012-40039-C02-01)LC and JRGO were both supported by Ramón y Cajal contracts(RYC-2009-04985 and RYC-2011-08983)
文摘We evaluated how historical storm events have shaped the current forest landscape in three Pyrenean subalpine forests(NE Spain).For this purpose we related forest damage estimations obtained from multi-temporal aerial photographic comparisons to the current forest typology generated from airborne Li DAR data, and we examined the role of past natural disturbance on the current spatial distribution of forest structural types.We found six forest structural types in the landscape: early regeneration(T1 and T2), young even-aged stands(T3), uneven-aged stands(T4) and adult stands(T5and T6).All of the types were related to the timing and severity of past storms, with early-regeneration structures being found in areas markedly affected in recent times, and adult stands predominating in those areas that had suffered lowest damage levels within the study period.In general, landscapes where high or medium levels of damage were recurrent also presented higher levels of spatial heterogeneity,whereas the opposite pattern was found in the less markedly affected landscape, characterized by thepresence of large regular patches.Our results show the critical role that storm regimes in terms of timing and severity of past storms can play in shaping current forest structure and future dynamics in subalpine forests.The knowledge gained could be used to help define alternative forest management strategies oriented toward the enhancement of landscape heterogeneity as a measure to face future environmental uncertainty.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1D1A3B07045079)。
文摘Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.
基金Sponsored by the Science and Technology Project of Beijing Municipal Administration Center of Parks(ZX2019,ZX2017)Beijing Science and Technology Plan Project(D171100001817001)
文摘This study used the dynamic headspace adsorption(DHS) to collect volatile organic compounds(VOCs) released from the Fokienia hodginsii forest in summer, and analyzed the the composition and concentration of VOCs and their correlation with environmental factors. The results showed that: there were 165 types of VOCs in the Fokienia hodginsii forest;the diurnal variation of the concentration of total volatile organic compounds(TVOCs) was "W"-shaped, the concentration reached its peak at 13:00–15:00 and its trough at 1:00–3:00;VOCs beneficial to human health mainly appeared at 13:00, while VOCs harmful to human health chiefly occurred at 11:00–19:00. The correlation analysis between the concentration of VOCs and climatic factors indicated that the concentration of VOCs was basically proportional to the temperature and illumination intensity and inversely proportional to the humidity and wind speed. In other words, the diurnal variation of the concentration was consistent with the diurnal variation of temperature and illumination intensity.
基金My great thanks goes to my colegue Dr.Abdu Abdulkadir who gave me his valuable comments how to organize the manuscript.His inputs were very important for the work to proceed forward.I also thank my friend and colegue Mr.Nesibu Yaya for helping me in editing the map of the study area.
文摘positively or negatively depending on the condition.Vegetation has influence on the soil physico-chemical characteristics.Land use land cover changes are the main factors in the process of land resource degradation.The objectives of this study were to define the soil texture,bulk density and extent of organic carbon in church forests and adjacent croplands and to compare the values.Transect lines of 100 meter apart and plots of 20 m×20 m were established to collect soil samples in the church forests and individual farm plots.The distance between plots was 100 m.Horizon based soil sampling was undertaken.Soil samples were collected on a diagonal position from 2 edges and the center from 2 soil horizons(H1 and H2)for soil texture and soil organic carbon(SOC)analysis.For bulk density(BD)soil core samplers were used.The data was analyzed using one way ANOVA in SPSS v20.Mean separation was undertaken by least significance difference.The results revealed the%clay content was significantly higher in croplands than church forests and the%sand was higher in church forests than croplands at(p<0.05).The SOC was significantly higher in H1 than H2 and in church forests than croplands at(p<0.05).The better soil characteristics were obtained in church forests than in croplands.Hence,it is recommended to conserve the natural forests as in the church forests to maintain better property of the soil through enhancing soil organic matter,soil organic carbon and by decreasing soil bulk density.
文摘Background： Growth and yield models are important tools for forest planning. Due to its geographic location, topology, and history of management, the forests of the Adirondacks Region of New York are unique and complex. However, only a relatively limited number of growth and yield models have been developed and/or can be reasonably extended to this region currently. Methods： in this analysis, 571 long-term continuous forest inventory plots with a total of 10 - 52 years of measurement data from four experimental forests maintained by the State University of New York College of Environmental Science and Forestry and one nonindustrial private forest were used to develop an individual tree growth model for the primary hardwood and softwood species in the region. Species-specific annualized static and dynamic equations were developed using the available data and the system was evaluated for long-term behavior. Results： Equivalence tests indicated that the Northeast Variant of the Forest Vegetation Simulator （FVS-NE） was biased in its estimation of tree total and bole height, diameter and height increment, and mortality for most species examined. In contrast, the developed static and annualized dynamic, species-specific equations performed quite well given the underlying variability in the data. Long-term model projections were consistent with the data and suggest a relatively robust system for prediction. Conclusions： Overall, the developed growth model showed reasonable behavior and is a significant improvement over existing models for the region. The model also highlighted the complexities of forest dynamics in the region and should help improve forest planning efforts there.
基金Asia-Pacifi c Network for Sustainable Forest Management and Rehabilitation SFM-ORE-2018。
文摘Innovation in forestry education is needed to address changing contexts of the positionality of forests.This is particularly signifi cant in the Asia–Pacifi c region,where deforestation and degradation are high.However,the accessibility of high-quality forestry education to address changing regional and global contexts is lacking.A series of innovative sustainable forest management(SFM)open education resource(OER)courses were developed and implemented to improve the accessibility of SFM education to enhance teaching quality,curriculum,and research capacity of universities in the Asia-Pacifi c Region.To evaluate the SFM-OER program in terms of student experiences,this study investigated student achievement,perceived success of the pedagogical approach and instructional design,and perceived eff ectiveness of the learning activities in promoting active and transformative learning through the assessment of a 1,191-course feedback survey between 2018 and 2020,including the global pandemic.This study revealed that the program attracted diverse student demographics,including a higher proportion of female students majoring in forestry,ecology,and other environmental studies.Their primary motivation to participate in the courses was to gain international experience,followed by the fl exibility of online learning,mandatory course requirements,and earning course credits.Students were satisfi ed with the Canvas learning management system.Most students spent less than 5 to 10 h of their weekly time in the course and agreed or strongly agreed that the workloads were manageable.Students refl ected positively on various learning activities and assignments,such as watching lecture videos,taking quizzes,reading and summarizing,having discussions,and peer review writing.However,they did not clearly prefer specifi c learning activities,signifying the importance of using diverse learning activities to satisfy diverse individual learning styles in online settings.This analysis contributes to the further development of student-centered pedagogical development for online learning and provides insight into the ways forward for online higher forestry education,while repurposing existing OER courses in a post-Covid-19 era.
文摘The effect of litter on forest regeneration depends on the characteristics of regional climate and also shows community specificity. The influences of plant litter on seed germination and seedling growth of Larch Siberian forest in the Altai Mountains were investigated through two simulated experiments including litter coverage and litter aqueous extracts. In the litter coverage experiment, three litter coverage methods including above (D), below (S) and in the middle (Z) of litter were set with the litter coverage thickness of 0, 1, 2, and 4 cm, while two aqueous extract obtained methods using the air-dried litter and litter ash after fir were used with the concentration of 10%, 40%, 80% and 100% in the present study. Results showed that: the aqueous extracts obtained using the air-dried litter restrained the seed germination, while the aqueous extracts obtained using litter ash improved the seed germination. Compared with other litter concentration, the influences of 100% concentration reach highest. The seed germination rate, seed germination potential and vital index under the treatment of seeds above the litter coverage were highest, which were significantly higher than other treatments. The above-ground biomass was significantly higher and the inhibition index of below-ground bio-mass was significantly lower under the treatment of seed above the litter with thin litter cover-age (S1) compared to other litter coverage treatments. These results indicated that the litter aqueous extract and the litter coverage had a combined effect on the seed germination and seedling growth of Siberian larch forest. Fire disturbance could promote seed germination by modifying the adverse effects of litter aqueous extracts and litter coverage, and thus plays an important role in the regeneration of Siberian larch in the Altai Mountains.
基金Sponsored by the Science and Technology Project of Beijing Municipal Administration Center of Parks(ZX2019)Beijing Science and Technology Plan Project(D171100001817001)
文摘With the Fokienia hodginsii forest in Qishan National Forest Park as the object of study, this study observed the diurnal variation of concentrations of atmospheric aerosol particles inside and outside the forest, collected the data of microclimate factors, and analyzed their correlation with the particle concentration. The results showed that the diurnal variation curves of the particle concentration of the forest and the forest edge had two peaks and two troughs". There were two peaks throughout the day at 13:00 and 19:00 or 17:00 as well as two troughs at 7:00-9:00 and 15:00 or 17:00. The atmospheric aerosol particle in the forest was mainly fine particles, while the forest edge was dominated by coarse particles. For the forest and the forest edge, the diurnal variation trends of various atmospheric aerosol particles were similar. The particle concentration was positively correlated with temperature, relative humidity, and il umination intensity and negatively correlated with wind speed, and the particle concentration outside the forest was significantly negatively correlated with the wind speed.
基金Sponsored by the Science and Technology Project of Beijing Municipal Administration Center of Parks(ZX2019)Beijing Science and Technology Plan Project(D171100001817001)
文摘This study analyzed the microclimate factors and human comfort index of the inner and outer Fokienia hodginsii forests and of a city square.The results showed that:①In terms of the average daily temperature,the inner and outer forests and the city square ranked as follows:square>outer forest>inner forest.The temperature of the inner forest was 8.21–11.73℃lower than that of the city square,and the temperature of the outer forest was 7.41–10.34℃lower than that of the city square.The inner forest was cooled by 24.21%and 1.37%respectively than the outer forest and the city square.②In terms of the average daily relative humidity,the inner and outer forests and the city square ranked as follows:square<outer forest<inner forest.The average daily relative humidity of the inner forest,the outer forest,and the city square was 68.57,84.91,and 88.27,respectively.③In terms of the average daily wind speed,the inner and outer forests and the city square ranked as:square>outer forest>inner forest.Their daily variation ranges were 0–0.75,0.18–0.43,and 0.12–0.31 m/s,respectively.④In terms of the daily average illumination intensity,the inner and outer forests and the square ranked as:square>outer forest>inner forest.Their average daily illumination intensities were 371.68,4,582.01,and 17,641.63 lux,respectively.
文摘Forestry plays an important role in maintaining the balance of the ecological environment and improving people's quality of life. It can also promote the development of related industries. At present, significant achievements have been made in forestry development, but the current situation of forest resources management is not optimistic and there are some deficiencies. This paper focuses on the management of forest resources, based on the analysis of potential problems, puts forward targeted improvement strategies to provide reference for related research.
