Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in ...Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in economic environment and practical experience,weaknesses in social participation,project scale and carbon sink talents,opportunities in international climate environment,domestic policies,etc.,and threats in project crediting period and forest resource protection,etc.In view of these,Yunnan Province can change the participation mode of forest carbon sink projects,adopt appropriate trading methods,get familiar with the relevant rules of forest carbon sink projects,strengthen the publicity and research of forest carbon sink theory,strengthen the management of carbon sink forests and expand forest carbon sink projects to enhance the market competitiveness of the Yunnan forest carbon sink projects.展开更多
[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promo...[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promote the development of green low-carbon economy in China.[Methods]Based on the data of six forest resource inventories from 1989 to 2018 and related studies,the comprehensive evaluation model of forest carbon sink and forestry economic development,the coupling degree model of forest carbon sink and forestry economic development,and the coupling coordination degree model of forest carbon sink and forestry economic development were adopted.The coupling degree of forest carbon sink and forestry economic development from 1992 to 2018 was analyzed.Stepwise regression and ARIMA model were used to analyze the influencing factors and lagging characteristics of forest carbon sink.The coupling degree between forest carbon sink and forestry economic development in China from 2019 to 2030 was predicted by autoregression and ADF test.The coupling between forest carbon sink and forestry economic development in China and its long-term change characteristics were also discussed in this study.[Results](i)The investment of ecological construction and protection,the actual investment of forestry key ecological projects,GDP and the import of forest products had a significant impact on forest resources carbon stock.The total output value of forestry industry,the actually completed investment of forestry key ecological projects and the export volume of forest products had a significant impact on the forest carbon sink,and the actually completed investment of forestry key ecological projects has the greatest impact on the two.(ii)The impact of actually completed investment of forestry key ecological projects had a lag of 2 years on the forest resources carbon stock and a lag of 1 year on the forest carbon sink.When investing in forest carbon sink,it is necessary to make a good plan in advance,and do a good job in forest resources management and time optimization.(iii)From 1992 to 2018,the coupling degree of forest resources carbon stock,forest carbon sink and long-term development of forestry economy in China was gradually increasing.Although there were some fluctuations in the middle time,the coupling degree of forest resources carbon stock and the long-term development of forestry economy increased by 9.24%annually,and the degree of coupling coordination increased from"serious imbalance"in 1992 to"high-quality coordination"in 2018.From 1993 to 2018,the coupling degree of forest carbon sink and long-term development of forestry economy increased by 9.63%annually,slightly faster than the coupling coordination degree of forest resources carbon stock and long-term development of forestry economy.The coordination level also rose from level 2 in 1993 to level 10 in 2018.(iv)The prediction shows that the coupling coordination degree of forest resources carbon stock,forest carbon sink and the long-term development of forestry economy would increase from 2019 to 2030.The coupling coordination degree(D)values of both were close to 1,the coordination level was also 10 for a long time,and the degree of coupling coordination was also maintained at the"high-quality coordination"level for a long time.[Conclusions]Forest has multiple benefits of society,economy and ecology,and forest carbon sink is only a benefit output.The long-term coupling analysis of forest carbon sink and forestry economic development is a key point to multiple benefit analysis.The analysis shows that the spillover effect and co-evolution effect of forest carbon sink in China are significant.From 1992 to 2018,the coupling coordination degree of forest carbon sink and forestry economic development was gradually rising.The prediction analysis also indicate that the coupling coordination degree between the forest carbon sink and the long-term development of forestry economy will remain at the level of"high-quality coordination"for a long time from 2019 to 2030.Therefore,improving the level of forest management and maintaining the current trend of increasing forest resources are the key to achieving the goal of carbon peaking and carbon neutrality in China.展开更多
Forest ecosystems play an important role in the global carbon cycle.The implementation of the United Nations Framework Convention on Climate Change(UNFCCC) and the Kyoto Protocol has made the study of forest ecosystem...Forest ecosystems play an important role in the global carbon cycle.The implementation of the United Nations Framework Convention on Climate Change(UNFCCC) and the Kyoto Protocol has made the study of forest ecosystem carbon cycling a hot topic of scientific research globally.This paper utilized Chinese national forest inventory data sets(for the periods 1984-1988 and 1999-2003),the vegetation map of China(1:1000000),and the spatially explicit net primary productivity(NPP) data sets derived with the remote sensing-based light use efficiency model(CASA model).We quantitatively estimated the spatial distribution of carbon sinks and sources of forest vegetation(with a resolution of 1 km) using the spatial downscaling technique.During the period 1984 to 2003 the forest vegetation in China represented a carbon sink.The total storage of carbon increased by 0.77 PgC,with a mean of 51.0TgCa 1.The total carbon sink was 0.88PgC and carbon source was 0.11 PgC during the study period.The carbon sink and carbon source of forest vegetation in China showed a clear spatial distribution pattern.Carbon sinks were mainly located in subtropical and temperate regions,with the highest values in Hainan Province,Hengduan mountain ranges,Changbai mountain ranges in Jilin,and south and northwest of the Da Hinggan Mountains;carbon sources were mainly distributed from the northeast to southwestern areas in China,with the highest values mainly concentrated in southern Yunnan Province,central Sichuan Basin,and northern Da Hinggan Mountains.Increase in NPP was strongly correlated with carbon sink strength.The regression model showed that more than 80% of the variation in the modeled carbon sinks in Northeast,Northern,Northwest and Southern China were explained by the variation in NPP increase.There was a strong relationship between carbon sink strength and forest stand age.展开更多
Estimation of the capacity of provincial forest carbon sinks in Chinese mainland using the CO2FIX model provides data support for the effective management of provincial regions. According to China’s Sixth National Fo...Estimation of the capacity of provincial forest carbon sinks in Chinese mainland using the CO2FIX model provides data support for the effective management of provincial regions. According to China’s Sixth National Forest Inventory, we estimate the capacities of original and new afforestation carbon sinks under the assumption of using the country’s non-forest land for afforestation and reforestation to achieve a new forested area of 57323200 ha. The carbon absorption capacity of China’s forest ecosystems estimated from 2005 to 2050 reaches 8.4 GtC. The absorption capacities of original forest and new afforestation respectively are 4.9 and 3.5 GtC. The annual capacity of all forest carbon sinks has a roughly decreasing trend. Inner Mongolia Autonomous Region, Yunnan, Sichuan and Heilongjiang provinces make major contributions to the carbon sink capacity.展开更多
Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation...Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation. Here using field inventory, we examined the carbon sink and mitigation potential of monospecific Deodar forest in the Kumrat valley, of Hindu Kush Himalaya, Region of Pakistan, at a different elevation. The elevation of monospecific Deodar forest ranges from 2300 to 2700 m (a.s.l). We divided the forest into three elevation classes (that is 2300 - 2400 m (EI) 2400 - 2500 m (EII) and 2500 - 2700 m (EIII) a.s.l respectively). In each elevation class, we laid out 09 sample plots (33*33 m2) for measuring carbon values in living tree biomass (LT), soil (SC), litter, dead wood, cone (LDWC) and understory vegetation (USV). Our results showed that the carbon density at EI was 432.37 ± 277.96 Mg·C-1, while the carbon density at EII and EIII was 668.35 ± 323.94 and 1016.79 ± 542.99 Mg·C-1 respectively. Our finding revealed that the carbon mitigation potential of the forest increases with increasing elevation. Among the different elevation classes, EIII stored significantly higher carbon due to the dominance of mature, old age, larger trees, and the minimum anthropogenic disturbance, whereas EI stored statistically lower carbon because of maximum anthropogenic disturbance, which resulted in the removal of mature and over-mature trees. Furthermore, our correlation analysis between tree height and carbon stock and basal area and LT carbon, underlines that the basal area is the stronger predictor of LT carbon estimation than height. Overall our results highlight that deodar forest stored 716.94 ± 462.06 Mg?C·ha-1. However, the rehabilitation, preservation and sustainable management of disturb forest located at a lower elevation could considerably improve carbon mitigation potential.展开更多
The study of China s carbon emissions and carbon sequestration potential is of great practical significance to the formulation of carbon neutrality strategies and methods of China.Carbon emission is an inevitable outc...The study of China s carbon emissions and carbon sequestration potential is of great practical significance to the formulation of carbon neutrality strategies and methods of China.Carbon emission is an inevitable outcome of the initial stage of economic development,especially the right of developing countries existence and development.The carbon emission of China has been maintained at a low level for a long time and reached the top of the world in 2005.However,per capita carbon emission was still only 46.28%of the United States in 2016.China s total CO_(2) emissions are expected to reach 17-19 Gt/a by 2030.To achieve the goal of carbon neutrality in 2060,the main problems are the low technical capacity of emission reduction and the unreasonable structure of energy consumption.Therefore,replacing coal with gas is one of the most effective ways of emission reduction.By 2060,the carbon sequestration capacity of forest vegetation will reach or exceed 759.14 Mt/a and the CO_(2) sequestration capacity will reach 2783.5 Mt/a.According to that,China s carbon intensity must reduce by 95.39%on the basis of the carbon intensity in 2017,reaching 640 t/100 million yuan.The carbon sequestration capacity of terrestrial vegetation(forest,grassland)will reach or exceed 1380.3 Mt/a and the CO_(2) sequestration capacity will reach 5069.3 Mt/a.According to that,China s carbon intensity must reduce by 91.07%on the basis of the carbon intensity in 2017,reach 1152 t C per 100 million yuan.展开更多
In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was construc...In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was constructed to evaluate the carbon emission risks of the construction industry in Hebei Province,China from 2005 to 2020.The results are shown as follows:(1)The overall carbon emissions of the construction industry in Hebei Province of China showed an inverted"V"-shaped evolution trend during the past 16 years.Tangshan and Shijiazhuang maintained high carbon emissions,while Langfang,Hengshui and Baoding saw rapid increases in carbon emissions.(2)The environmental safety threshold of carbon emission from the construction industry in Hebei Province,China,has been continuously improved,and the provincial environmental safety threshold is between 9475080-23144760 tons;The environmental safety threshold was the highest in Baoding and Langfang,and the lowest in Xingtai.(3)In the past 16 years,the carbon emission risk of the construction industry in Hebei Province of China has been in a state of extremely serious risk,and the risk index generally presents an inverted"V"type trend.(4)The carbon emission risk of Hebei city in China presents a spatial pattern of"high in the south and low in the north",which goes through two stages:risk increase period and risk reduction period.展开更多
Carbon sequestration potential of tree species within forest reserves and other sites in Makurdi Benue state of Nigeria was investigated using non-destructive Walkley-Black technique. The result indicates that P. amer...Carbon sequestration potential of tree species within forest reserves and other sites in Makurdi Benue state of Nigeria was investigated using non-destructive Walkley-Black technique. The result indicates that P. americana has the highest CO2 sequestration potential (125,916.7 kg), while T. grandis (10.4 kg) and D. regia (26.1 kg) were the least. The study also shows that trees (T. grandis, S. actinophylla and P. americana) with thick vegetation, broad and clustered leaves were found to be better CO2 sequesters. The relationship between the tree height and amount of CO2 sequestered gave a regression equation of y = 67898x + 9509 with R2 = 0.266, indicating insignificant variations existing between tree height and CO2 sequestration at P > 0.05. Variations however existed between tree dominance and CO2 sequestration among trees investigated. This finding strategically positions Benue tropical forest in line for carbon credit financing while substantiating the importance of preserving our indigenous forest and tree species.展开更多
Secondary forests, created after heavy logging,are an important part of China's forests. We investigated forest biomass and its accumulation rate in 38 plots in a tropical secondary forest on Hainan Island. These ...Secondary forests, created after heavy logging,are an important part of China's forests. We investigated forest biomass and its accumulation rate in 38 plots in a tropical secondary forest on Hainan Island. These secondary forests are moderate carbon sinks, averaging1.96–2.17 t C ha-1 a-1. Biomass increment is largely by medium-sized(10–35 m) trees. Tree mortality accounts for almost 30% of the biomass and plays a negligible role in biomass accumulation estimates. Mortality rate is highly dependent on tree size. For small trees and seedlings, it is related to competition due to elevated irradiance after logging. Regarding prospective biomass and rates of accumulation, recovery is not as rapid as in secondary forests of cleared land. Therefore, tropical forests are susceptible to logging operations and need careful forest management.展开更多
Cities play a pivotal role in global decarbonization,acting as a critical driver of carbon emissions.Accurately allocating carbon mitigation responsibility(CMR)is essential for designing effective and equitable climat...Cities play a pivotal role in global decarbonization,acting as a critical driver of carbon emissions.Accurately allocating carbon mitigation responsibility(CMR)is essential for designing effective and equitable climate policies.How cities manage carbon leakage across boundaries through supply chains and implement plan of increasing forest carbon sinks are important components for designing a fair and inclusive CMR.However,the combined impact of trade-related carbon leakage and forest carbon sinks on CMR allocation remains poorly understood.Here,we develop an integrated CMR allocation framework that accounts for both carbon leakage and variation of forest carbon offsets.When applied to the cities within the GuangdongeHong KongeMacao Greater Bay Area in China,it becomes evident that the in-clusion of carbon leakage results in substantial alterations in mitigation quotas.Adjustments are observed to vary between±10%and 50%across these cities from 2005 to 2020,a trend that is anticipated to continue until 2035.The redistribution of outsourced emissions through supply chains alleviates the mitigation burden on producer cities by 20e30%.Additionally,accounting for carbon sinks substantially influences CMR allocation,particularly in forest-rich cities,which may see their carbon budgets increase by up to 10%.Under an enhanced climate policy scenario,the growth rate of total mitigation quotas from 2025 to 2035 is projected to decrease by 40%compared to a business-as-usual trajectory,reducing the burden on major producer cities.Our proposed CMR framework provides a robust basis for incentivizing coordinated mitigation efforts,promoting decarbonization in supply chains and enhancement of urban carbon sink capacities.展开更多
文摘Using the SWOT analysis method,this paper analyzed the internal strengths,weaknesses,external opportunities and threats of forest carbon sink projects in Yunnan Province.It found that Yunnan Province has strengths in economic environment and practical experience,weaknesses in social participation,project scale and carbon sink talents,opportunities in international climate environment,domestic policies,etc.,and threats in project crediting period and forest resource protection,etc.In view of these,Yunnan Province can change the participation mode of forest carbon sink projects,adopt appropriate trading methods,get familiar with the relevant rules of forest carbon sink projects,strengthen the publicity and research of forest carbon sink theory,strengthen the management of carbon sink forests and expand forest carbon sink projects to enhance the market competitiveness of the Yunnan forest carbon sink projects.
基金Supported by National Natural Science Foundation of China(72173011).
文摘[Objectives]To analyze the changes in of forest carbon sink and forestry economic development,provide reference for relevant management decisions,ecological governance and resource and environment management,and promote the development of green low-carbon economy in China.[Methods]Based on the data of six forest resource inventories from 1989 to 2018 and related studies,the comprehensive evaluation model of forest carbon sink and forestry economic development,the coupling degree model of forest carbon sink and forestry economic development,and the coupling coordination degree model of forest carbon sink and forestry economic development were adopted.The coupling degree of forest carbon sink and forestry economic development from 1992 to 2018 was analyzed.Stepwise regression and ARIMA model were used to analyze the influencing factors and lagging characteristics of forest carbon sink.The coupling degree between forest carbon sink and forestry economic development in China from 2019 to 2030 was predicted by autoregression and ADF test.The coupling between forest carbon sink and forestry economic development in China and its long-term change characteristics were also discussed in this study.[Results](i)The investment of ecological construction and protection,the actual investment of forestry key ecological projects,GDP and the import of forest products had a significant impact on forest resources carbon stock.The total output value of forestry industry,the actually completed investment of forestry key ecological projects and the export volume of forest products had a significant impact on the forest carbon sink,and the actually completed investment of forestry key ecological projects has the greatest impact on the two.(ii)The impact of actually completed investment of forestry key ecological projects had a lag of 2 years on the forest resources carbon stock and a lag of 1 year on the forest carbon sink.When investing in forest carbon sink,it is necessary to make a good plan in advance,and do a good job in forest resources management and time optimization.(iii)From 1992 to 2018,the coupling degree of forest resources carbon stock,forest carbon sink and long-term development of forestry economy in China was gradually increasing.Although there were some fluctuations in the middle time,the coupling degree of forest resources carbon stock and the long-term development of forestry economy increased by 9.24%annually,and the degree of coupling coordination increased from"serious imbalance"in 1992 to"high-quality coordination"in 2018.From 1993 to 2018,the coupling degree of forest carbon sink and long-term development of forestry economy increased by 9.63%annually,slightly faster than the coupling coordination degree of forest resources carbon stock and long-term development of forestry economy.The coordination level also rose from level 2 in 1993 to level 10 in 2018.(iv)The prediction shows that the coupling coordination degree of forest resources carbon stock,forest carbon sink and the long-term development of forestry economy would increase from 2019 to 2030.The coupling coordination degree(D)values of both were close to 1,the coordination level was also 10 for a long time,and the degree of coupling coordination was also maintained at the"high-quality coordination"level for a long time.[Conclusions]Forest has multiple benefits of society,economy and ecology,and forest carbon sink is only a benefit output.The long-term coupling analysis of forest carbon sink and forestry economic development is a key point to multiple benefit analysis.The analysis shows that the spillover effect and co-evolution effect of forest carbon sink in China are significant.From 1992 to 2018,the coupling coordination degree of forest carbon sink and forestry economic development was gradually rising.The prediction analysis also indicate that the coupling coordination degree between the forest carbon sink and the long-term development of forestry economy will remain at the level of"high-quality coordination"for a long time from 2019 to 2030.Therefore,improving the level of forest management and maintaining the current trend of increasing forest resources are the key to achieving the goal of carbon peaking and carbon neutrality in China.
基金supported by the National Basic Research Program of China (2012CB955401)the National Natural Science Foundation of China (30970514 and 30590384)the New Century Excellent Talents in University (NCET-10-0251)
文摘Forest ecosystems play an important role in the global carbon cycle.The implementation of the United Nations Framework Convention on Climate Change(UNFCCC) and the Kyoto Protocol has made the study of forest ecosystem carbon cycling a hot topic of scientific research globally.This paper utilized Chinese national forest inventory data sets(for the periods 1984-1988 and 1999-2003),the vegetation map of China(1:1000000),and the spatially explicit net primary productivity(NPP) data sets derived with the remote sensing-based light use efficiency model(CASA model).We quantitatively estimated the spatial distribution of carbon sinks and sources of forest vegetation(with a resolution of 1 km) using the spatial downscaling technique.During the period 1984 to 2003 the forest vegetation in China represented a carbon sink.The total storage of carbon increased by 0.77 PgC,with a mean of 51.0TgCa 1.The total carbon sink was 0.88PgC and carbon source was 0.11 PgC during the study period.The carbon sink and carbon source of forest vegetation in China showed a clear spatial distribution pattern.Carbon sinks were mainly located in subtropical and temperate regions,with the highest values in Hainan Province,Hengduan mountain ranges,Changbai mountain ranges in Jilin,and south and northwest of the Da Hinggan Mountains;carbon sources were mainly distributed from the northeast to southwestern areas in China,with the highest values mainly concentrated in southern Yunnan Province,central Sichuan Basin,and northern Da Hinggan Mountains.Increase in NPP was strongly correlated with carbon sink strength.The regression model showed that more than 80% of the variation in the modeled carbon sinks in Northeast,Northern,Northwest and Southern China were explained by the variation in NPP increase.There was a strong relationship between carbon sink strength and forest stand age.
基金supported by the National Natural Science Foundation of China (40771076)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-325-7)
文摘Estimation of the capacity of provincial forest carbon sinks in Chinese mainland using the CO2FIX model provides data support for the effective management of provincial regions. According to China’s Sixth National Forest Inventory, we estimate the capacities of original and new afforestation carbon sinks under the assumption of using the country’s non-forest land for afforestation and reforestation to achieve a new forested area of 57323200 ha. The carbon absorption capacity of China’s forest ecosystems estimated from 2005 to 2050 reaches 8.4 GtC. The absorption capacities of original forest and new afforestation respectively are 4.9 and 3.5 GtC. The annual capacity of all forest carbon sinks has a roughly decreasing trend. Inner Mongolia Autonomous Region, Yunnan, Sichuan and Heilongjiang provinces make major contributions to the carbon sink capacity.
文摘Forest carbon monitoring and reporting are critical for informing global climate change assessment. The regional estimates of forest carbon attached greater attention, to assess the role of forest in carbon mitigation. Here using field inventory, we examined the carbon sink and mitigation potential of monospecific Deodar forest in the Kumrat valley, of Hindu Kush Himalaya, Region of Pakistan, at a different elevation. The elevation of monospecific Deodar forest ranges from 2300 to 2700 m (a.s.l). We divided the forest into three elevation classes (that is 2300 - 2400 m (EI) 2400 - 2500 m (EII) and 2500 - 2700 m (EIII) a.s.l respectively). In each elevation class, we laid out 09 sample plots (33*33 m2) for measuring carbon values in living tree biomass (LT), soil (SC), litter, dead wood, cone (LDWC) and understory vegetation (USV). Our results showed that the carbon density at EI was 432.37 ± 277.96 Mg·C-1, while the carbon density at EII and EIII was 668.35 ± 323.94 and 1016.79 ± 542.99 Mg·C-1 respectively. Our finding revealed that the carbon mitigation potential of the forest increases with increasing elevation. Among the different elevation classes, EIII stored significantly higher carbon due to the dominance of mature, old age, larger trees, and the minimum anthropogenic disturbance, whereas EI stored statistically lower carbon because of maximum anthropogenic disturbance, which resulted in the removal of mature and over-mature trees. Furthermore, our correlation analysis between tree height and carbon stock and basal area and LT carbon, underlines that the basal area is the stronger predictor of LT carbon estimation than height. Overall our results highlight that deodar forest stored 716.94 ± 462.06 Mg?C·ha-1. However, the rehabilitation, preservation and sustainable management of disturb forest located at a lower elevation could considerably improve carbon mitigation potential.
文摘The study of China s carbon emissions and carbon sequestration potential is of great practical significance to the formulation of carbon neutrality strategies and methods of China.Carbon emission is an inevitable outcome of the initial stage of economic development,especially the right of developing countries existence and development.The carbon emission of China has been maintained at a low level for a long time and reached the top of the world in 2005.However,per capita carbon emission was still only 46.28%of the United States in 2016.China s total CO_(2) emissions are expected to reach 17-19 Gt/a by 2030.To achieve the goal of carbon neutrality in 2060,the main problems are the low technical capacity of emission reduction and the unreasonable structure of energy consumption.Therefore,replacing coal with gas is one of the most effective ways of emission reduction.By 2060,the carbon sequestration capacity of forest vegetation will reach or exceed 759.14 Mt/a and the CO_(2) sequestration capacity will reach 2783.5 Mt/a.According to that,China s carbon intensity must reduce by 95.39%on the basis of the carbon intensity in 2017,reaching 640 t/100 million yuan.The carbon sequestration capacity of terrestrial vegetation(forest,grassland)will reach or exceed 1380.3 Mt/a and the CO_(2) sequestration capacity will reach 5069.3 Mt/a.According to that,China s carbon intensity must reduce by 91.07%on the basis of the carbon intensity in 2017,reach 1152 t C per 100 million yuan.
基金supported by the Hebei Social Science Foundation Project(Grant No.HB20YJ018)2023 Hebei Province Social Science Development Research Project(Grant No.20230103005)Education Department of Hebei Province Graduate Student Innovation Ability Training Funding Project(Grant No.CXZZSS2023130).
文摘In order to assess the environmental risks caused by carbon emissions from the construction industry in Hebei Province of China,an environmental risk assessment model based on forest carbon sink threshold was constructed to evaluate the carbon emission risks of the construction industry in Hebei Province,China from 2005 to 2020.The results are shown as follows:(1)The overall carbon emissions of the construction industry in Hebei Province of China showed an inverted"V"-shaped evolution trend during the past 16 years.Tangshan and Shijiazhuang maintained high carbon emissions,while Langfang,Hengshui and Baoding saw rapid increases in carbon emissions.(2)The environmental safety threshold of carbon emission from the construction industry in Hebei Province,China,has been continuously improved,and the provincial environmental safety threshold is between 9475080-23144760 tons;The environmental safety threshold was the highest in Baoding and Langfang,and the lowest in Xingtai.(3)In the past 16 years,the carbon emission risk of the construction industry in Hebei Province of China has been in a state of extremely serious risk,and the risk index generally presents an inverted"V"type trend.(4)The carbon emission risk of Hebei city in China presents a spatial pattern of"high in the south and low in the north",which goes through two stages:risk increase period and risk reduction period.
文摘Carbon sequestration potential of tree species within forest reserves and other sites in Makurdi Benue state of Nigeria was investigated using non-destructive Walkley-Black technique. The result indicates that P. americana has the highest CO2 sequestration potential (125,916.7 kg), while T. grandis (10.4 kg) and D. regia (26.1 kg) were the least. The study also shows that trees (T. grandis, S. actinophylla and P. americana) with thick vegetation, broad and clustered leaves were found to be better CO2 sequesters. The relationship between the tree height and amount of CO2 sequestered gave a regression equation of y = 67898x + 9509 with R2 = 0.266, indicating insignificant variations existing between tree height and CO2 sequestration at P > 0.05. Variations however existed between tree dominance and CO2 sequestration among trees investigated. This finding strategically positions Benue tropical forest in line for carbon credit financing while substantiating the importance of preserving our indigenous forest and tree species.
基金supported by The C-project Excellent Talent Project of Hainan Universitythe National Natural Science Foundation of China(Grant No.31200347)
文摘Secondary forests, created after heavy logging,are an important part of China's forests. We investigated forest biomass and its accumulation rate in 38 plots in a tropical secondary forest on Hainan Island. These secondary forests are moderate carbon sinks, averaging1.96–2.17 t C ha-1 a-1. Biomass increment is largely by medium-sized(10–35 m) trees. Tree mortality accounts for almost 30% of the biomass and plays a negligible role in biomass accumulation estimates. Mortality rate is highly dependent on tree size. For small trees and seedlings, it is related to competition due to elevated irradiance after logging. Regarding prospective biomass and rates of accumulation, recovery is not as rapid as in secondary forests of cleared land. Therefore, tropical forests are susceptible to logging operations and need careful forest management.
基金supported by the National Key Research and Development Program of China[No.2022YFF1301200]the National Natural Science Foundation of China[No.72074232 and No.42477514]the Major Project of the National Social Science Fund of China[No.22&ZD108].
文摘Cities play a pivotal role in global decarbonization,acting as a critical driver of carbon emissions.Accurately allocating carbon mitigation responsibility(CMR)is essential for designing effective and equitable climate policies.How cities manage carbon leakage across boundaries through supply chains and implement plan of increasing forest carbon sinks are important components for designing a fair and inclusive CMR.However,the combined impact of trade-related carbon leakage and forest carbon sinks on CMR allocation remains poorly understood.Here,we develop an integrated CMR allocation framework that accounts for both carbon leakage and variation of forest carbon offsets.When applied to the cities within the GuangdongeHong KongeMacao Greater Bay Area in China,it becomes evident that the in-clusion of carbon leakage results in substantial alterations in mitigation quotas.Adjustments are observed to vary between±10%and 50%across these cities from 2005 to 2020,a trend that is anticipated to continue until 2035.The redistribution of outsourced emissions through supply chains alleviates the mitigation burden on producer cities by 20e30%.Additionally,accounting for carbon sinks substantially influences CMR allocation,particularly in forest-rich cities,which may see their carbon budgets increase by up to 10%.Under an enhanced climate policy scenario,the growth rate of total mitigation quotas from 2025 to 2035 is projected to decrease by 40%compared to a business-as-usual trajectory,reducing the burden on major producer cities.Our proposed CMR framework provides a robust basis for incentivizing coordinated mitigation efforts,promoting decarbonization in supply chains and enhancement of urban carbon sink capacities.
