Urban areas are a major source of anthropogenic carbon dioxide (CO<sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">) emissions ...Urban areas are a major source of anthropogenic carbon dioxide (CO<sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">) emissions because of road traffic and local heating with natural gas, oil or coal. Rome is among the largest European cities (129,000 ha) with a large volume of green areas (69.6% of the total Municipality area). The CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration (CS) capability for the greenery extending for about 300 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> inside the area delimited by the Great Ring Road (GRA) in Rome was calculated combining satellite data with CS data measured in the field. Data from Sentinel-2 were collected and the Normalized Difference Vegetation Index (NDVI) was computed on a pixel-base. Three plant classes homogeneous in terms of annual NDVI profile were identified: deciduous trees (DT), evergreen trees (ET) and meadows (M) covering an area of 14,142.027 ha within the GRA, of which M had the highest percentage (48%), followed by DT (27%) and ET (25%). CS ranged from 428,241</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;">492.9 </span><span style="font-family:Verdana;">T</span><span style="font-family:;" "=""><span style="font-family:Verdana;">ons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> (ET) to 263,072</span></span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;">460.6 Tons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> (M). The total CS of the greenery inside the GRA was 1049,490,355.4 Tons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> resulting in an annual economic value of $772,424,901.6/ha. The CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration capability of the considered plant classes could be incorporated into the national greenhouse gas emission budget to calculate the contribution of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration to the economy of Rome.</span></span>展开更多
Beech stands are considered part of the ancient forest ecosystems in the northern hemisphere.In mixed stands in beach forest ecosystems,the type of associated tree species can signifi cantly aff ect soil functions,but...Beech stands are considered part of the ancient forest ecosystems in the northern hemisphere.In mixed stands in beach forest ecosystems,the type of associated tree species can signifi cantly aff ect soil functions,but their infl uence on microbial activity,nutrient cycling and belowground properties is unknown.Here,we considered forest patches in northern Iran that are dominated by diff erent tree species:Fagus orientalis Lipsky,Quercus castaneifolia C.A.Mey.,Pterocarya fraxinifolia(Lam.),Tilia begonifolia Stev.,Zelkova carpinifolia Dippe,Acer cappadocicum Gled,Acer velutinum Boiss.,Fraxinus excelsior L.,Carpinus betulus L.,and Alnus subcordata C.A.Mey.For each forest patch–tree species,litter and soil samples(25×25×10 cm,100 of each)were analyzed for determine soil and litter properties and their relationship with tree species.The litter decomposition rate during a 1-year experiment was also determined.A PCA showed a clear diff erence between selected litter and soil characteristics among tree species.F.orientalis,Q.castaneifolia,P.fraxinifolia,T.begonifolia,Z.carpinifolia,A.cappadocicum,and A.velutinum enhanced soil microbial biomass of carbon,whereas patches with F.excelsior,C.betulus and A.subcordata had faster litter decomposition and enhanced biotic activities and C and N dynamics.Thus,soil function indicators were species-specifi c in the mixed beech forest.A.subcordata(a N-fi xing species),C.betulus and F.excelsior were main drivers of microbial activities related to nutrient cycling in the old-growth beech forest.展开更多
Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant func...Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.展开更多
Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The ob...Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes： a pine forest mixed with deciduous species（S1）; a Quercus spp.forest（S2）; and,a Tamaulipan thornscrub forest（S3）.Total annual litterfall deposition was 594,742 and 533 g m^（-2） for S1,S2 and S3.Leaf litter was higher （68%） than twigs（18%）,reproductive structures（8%） or miscellaneous material（6%）.Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes（550 m）.Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.展开更多
Exploring the response differences of leaf physiology parameters to enhanced nitrogen deposition between saplings and trees is vital for predicting the variations of terrestrial ecosystem structure and function under ...Exploring the response differences of leaf physiology parameters to enhanced nitrogen deposition between saplings and trees is vital for predicting the variations of terrestrial ecosystem structure and function under future global climate change. In this study, the ecophysiological parameters of saplings and trees of Fraxinus mandshurica Rupr. were measured at different levels of nitrogen addition in a temperate forest. The results show that ecophysiological parameters maximum net photosynthetic rate(Pmax), apparent quantum efficiency(a), dark respiration(Rd), light saturation point(Lsp), photosynthetic nitrogen use efficiency(PNUE),specific leaf area(SLA)and stomatal conductance under saturated light intensity(Gsmax) were higher in saplings than in trees. These physiological parameters and not Nleaf(leaf nitrogen content)led to relatively lower Pmaxand Rdin trees. For both saplings and trees, low and median nitrogen addition(23 and 46 kg ha-1a-1) resulted in significant increases in Pmax, Rd, Lsp, Chl, PNUE, SLA and Gsmax. These parameters tended to decline under high additions of nitrogen(69 kg ha-1a-1),whereas Nleaf was always enhanced with increasing nitrogen. Variations in Pmax and Rd with increasing nitrogen were attributed to variations in the strongly related parameters of, Lsp, Chl, PNUE, SLA and Gsmax. Overall, the response sensitivity of physiological parameters to enhanced nitrogen levels was lower in trees compared with saplings.展开更多
文摘Urban areas are a major source of anthropogenic carbon dioxide (CO<sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">) emissions because of road traffic and local heating with natural gas, oil or coal. Rome is among the largest European cities (129,000 ha) with a large volume of green areas (69.6% of the total Municipality area). The CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration (CS) capability for the greenery extending for about 300 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> inside the area delimited by the Great Ring Road (GRA) in Rome was calculated combining satellite data with CS data measured in the field. Data from Sentinel-2 were collected and the Normalized Difference Vegetation Index (NDVI) was computed on a pixel-base. Three plant classes homogeneous in terms of annual NDVI profile were identified: deciduous trees (DT), evergreen trees (ET) and meadows (M) covering an area of 14,142.027 ha within the GRA, of which M had the highest percentage (48%), followed by DT (27%) and ET (25%). CS ranged from 428,241</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;">492.9 </span><span style="font-family:Verdana;">T</span><span style="font-family:;" "=""><span style="font-family:Verdana;">ons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> (ET) to 263,072</span></span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;">460.6 Tons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> (M). The total CS of the greenery inside the GRA was 1049,490,355.4 Tons CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> year</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> resulting in an annual economic value of $772,424,901.6/ha. The CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration capability of the considered plant classes could be incorporated into the national greenhouse gas emission budget to calculate the contribution of CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> sequestration to the economy of Rome.</span></span>
基金Tarbiat Modares University for the financial support of the study reported in this paper
文摘Beech stands are considered part of the ancient forest ecosystems in the northern hemisphere.In mixed stands in beach forest ecosystems,the type of associated tree species can signifi cantly aff ect soil functions,but their infl uence on microbial activity,nutrient cycling and belowground properties is unknown.Here,we considered forest patches in northern Iran that are dominated by diff erent tree species:Fagus orientalis Lipsky,Quercus castaneifolia C.A.Mey.,Pterocarya fraxinifolia(Lam.),Tilia begonifolia Stev.,Zelkova carpinifolia Dippe,Acer cappadocicum Gled,Acer velutinum Boiss.,Fraxinus excelsior L.,Carpinus betulus L.,and Alnus subcordata C.A.Mey.For each forest patch–tree species,litter and soil samples(25×25×10 cm,100 of each)were analyzed for determine soil and litter properties and their relationship with tree species.The litter decomposition rate during a 1-year experiment was also determined.A PCA showed a clear diff erence between selected litter and soil characteristics among tree species.F.orientalis,Q.castaneifolia,P.fraxinifolia,T.begonifolia,Z.carpinifolia,A.cappadocicum,and A.velutinum enhanced soil microbial biomass of carbon,whereas patches with F.excelsior,C.betulus and A.subcordata had faster litter decomposition and enhanced biotic activities and C and N dynamics.Thus,soil function indicators were species-specifi c in the mixed beech forest.A.subcordata(a N-fi xing species),C.betulus and F.excelsior were main drivers of microbial activities related to nutrient cycling in the old-growth beech forest.
基金supported by the Key Area Research and Development Program of Guangdong Province(2022B1111230001)theScience and Technology Foundation of Guangxi Zhuang Autonomous Region(Guike AD23026080)+1 种基金the National Natural Science Founda tion of China(No.42071065)Natural Science Foundation of US(No.2021898).
文摘Deciduous oaks(Quercus spp.)are distributed from subalpine to tropical regions in the northern hemi-sphere and have important roles as carbon sinks and in climate change mitigation.Determining variations in plant functional traits at multiple biological levels and linking them to environmental variables across geographical ranges is important for forecasting range-shifts of broadly-distrib-uted species under climate change.We sampled leaves of five deciduous Quercus spp.covering approximately 20°of latitude(~21°N-41°N)and 20 longitude(~99°E-119°E)across China and measured 12 plant functional traits at different biological levels.The traits varied distinctively,either within each biological level or among different levels driven by climatic and edaphic variables.Traits at the organ level were significantly correlated with those at the cellular and tissue levels,while traits at the whole-plant level only correlated with those at the tissue level.The Quercus species responded to changing environments by regulating stomatal size,leaf thickness and the palisade mesophyll thickness to leaf thickness ratios with contrasting degree of effect to adjust the whole-plant functioning,i.e.,intrinsic water use efficiency(iWUE),carbon supply and nitrogen availability.The results suggest that these deciduous Quercus spp.will maintain vigour by increasing iWUE when subjected to large temperature changes and insufficient moisture,and by accu-mulating leaf non-structural carbohydrates under drought conditions.The findings provide new insights into the inher-ent variation and trait coordination of widely distributed tree species in the context of climate change.
基金supported by the PAICYT Grant CT259-15National Science and Technological Council(Grant250732)
文摘Studies on litterfall and decomposition provide estimations of decomposition rates of different ecosystems.This is key information to understanding ecosystem dynamics and changes in a scenario of global warming.The objective of this research was to assess litterfall production,the potential deposition of macro and micronutrients through leaf and twig fall as well as macronutrient—use efficiency in three forest ecosystems at different altitudes： a pine forest mixed with deciduous species（S1）; a Quercus spp.forest（S2）; and,a Tamaulipan thornscrub forest（S3）.Total annual litterfall deposition was 594,742 and 533 g m^（-2） for S1,S2 and S3.Leaf litter was higher （68%） than twigs（18%）,reproductive structures（8%） or miscellaneous material（6%）.Micronutrient leaf deposition was higher for Fe followed by Mn,Zn and Cu.Macronutrient leaf deposition was higher for Ca followed by K,Mg and P.Even though P deposition in leaves and twigs was lower than other macronutrients,its nutrient use efficiency was higher than Ca,Mg or K.Altitude and species composition determine litter and nutrient deposition,with higher values at mid-altitudes（550 m）.Altitude is an important factor to consider when analyzing litter production as well as nutrient deposition as shown in this study.Litter production and nutrient deposition are expected to change in a scenario of global warming.
基金funded by the National Key Research and Development Program of China(2016YFC0400206-04,2017YFC0505304)the National Natural Science Foundation of China(51309016)+1 种基金Central Public-interest Scientific Institution Basal Research Fund(CKSF2016007/TB)Changjiang River Scientific Research Institute Innovation Team(CKSF2017064/NS)
文摘Exploring the response differences of leaf physiology parameters to enhanced nitrogen deposition between saplings and trees is vital for predicting the variations of terrestrial ecosystem structure and function under future global climate change. In this study, the ecophysiological parameters of saplings and trees of Fraxinus mandshurica Rupr. were measured at different levels of nitrogen addition in a temperate forest. The results show that ecophysiological parameters maximum net photosynthetic rate(Pmax), apparent quantum efficiency(a), dark respiration(Rd), light saturation point(Lsp), photosynthetic nitrogen use efficiency(PNUE),specific leaf area(SLA)and stomatal conductance under saturated light intensity(Gsmax) were higher in saplings than in trees. These physiological parameters and not Nleaf(leaf nitrogen content)led to relatively lower Pmaxand Rdin trees. For both saplings and trees, low and median nitrogen addition(23 and 46 kg ha-1a-1) resulted in significant increases in Pmax, Rd, Lsp, Chl, PNUE, SLA and Gsmax. These parameters tended to decline under high additions of nitrogen(69 kg ha-1a-1),whereas Nleaf was always enhanced with increasing nitrogen. Variations in Pmax and Rd with increasing nitrogen were attributed to variations in the strongly related parameters of, Lsp, Chl, PNUE, SLA and Gsmax. Overall, the response sensitivity of physiological parameters to enhanced nitrogen levels was lower in trees compared with saplings.
