In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic chara...In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has the potential to be an effective approach for establishing multifunctional forest.展开更多
A new model was developed to predict forestland demand of China during the years of 2010-2050 in terms of the concept of forest ecosystem services. On the basis of the relationship between forest ecosystem services an...A new model was developed to predict forestland demand of China during the years of 2010-2050 in terms of the concept of forest ecosystem services. On the basis of the relationship between forest ecosystem services and classified forest management, we hypothesized that the ecological-forest provides ecological services, whereas commercial-forest supplies wood and timber production, and the influences of the growth of population, social-economic development target, forest management methods and the technology changes on forest resources were also taken into account. The prediction reveals that the demand of total forestland of China will be 244.8, 261.2 and 362.2 million ha by the year 2010, 2020 and 2050, respectively. The results demonstrated that China will be confronted with a shortage of forest resources, especially with lack of ecological-oriented forests, in the future. It is suggested that sustainable management of forest resources must be reinforced and more attention should be drown no enhancing the service function of forest ecosystem.展开更多
Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Fo...Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Forestry and Other Land Use Change (FOLU) subsector in Malawi. The results indicate that “forestland to cropland,” and “wetland to cropland,” were the major land use changes from the year 2000 to the year 2022. The forestland steadily declined at a rate of 13,591 ha (0.5%) per annum. Similarly, grassland declined at the rate of 1651 ha (0.5%) per annum. On the other hand, cropland, wetland, and settlements steadily increased at the rate of 8228 ha (0.14%);5257 ha (0.17%);and 1941 ha (8.1%) per annum, respectively. Furthermore, the results indicate that the “grassland to forestland” changes were higher than the “forestland to grassland” changes, suggesting that forest regrowth was occurring. On the emission factor, the results interestingly indicate that there was a significant increase in carbon sequestration in the FOLU subsector from the year 2011 to 2022. Carbon sequestration increased annually by 13.66 ± 0.17 tCO<sub>2</sub> e/ha/yr (4.6%), with an uncertainty of 2.44%. Therefore, it can be concluded that there is potential for a Carbon market in Malawi.展开更多
Based on data observed from 1989 to 1998 in the Ziwuling survey station, changes of soil erosion and soil physico-mechanical properties were studied after forestland reclamation. When the man-induced fac...Based on data observed from 1989 to 1998 in the Ziwuling survey station, changes of soil erosion and soil physico-mechanical properties were studied after forestland reclamation. When the man-induced factors changed the eco-environment by reclaiming forestlands, the intensity of man-made soil erosion in reclaimed lands was 1,000 times more than that of natural erosion in forestlands. From the analysis of soil physical and mechanical properties, the clay content and physical clay content decreased 2.74% and 3.01% respectively, and the >0.25 mm water stable aggregate content decreased 58.7%, the soil unit weight increased and the soil shear strength decreased, all of which were easier to cause soil erosion. The results of the correlation analysis showed that the >0.25 mm water stable aggregate content was the greatest influencing factor on soil erosion, the partial correlated coefficient was 0.9728, and then were soil coarse grain and soil shear strength, the partial correlated coefficients being 0.8879 and 0.6020 respectively. The relationships between the >0.25 mm water stable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed, which showed that the first and seventh years were the turning years of the soil erosion intensity after the forestland reclamation. The degenerative eroded soil and eco-environment formed the peculiar erosion environment, which aggravated the soil erosion rapidly.展开更多
Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell...Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell in cap-and-trade programs. The California’s cap-and-trade program (California’s carbon market hereafter) allows forestland owners from any part of the contiguous United States to supply carbon credits to compliance entities. In this study, we estimate South Carolina (SC) private forestland owners’willingness to accept compensations to participate in the California’s carbon market using a contingent valuation method. Results: We estimate forestland owners’mean willingness to accept as$67 per acre per year. Our results reveal higher probability of participation of forestland owners with interests in preserving forest ecosystems than those who do not. Additionally, forestland owners who trust in information about climate change from scientists or government are willing to participate more than those who do not. Conclusions: Various factors hinder landowners’ability to participate in carbon markets. Forestland owners in SC consider legislative uncertainty and long-time commitment as the main barriers to participation in California’s carbon market. From this research, average forestland tenure in SC is 27 years, which is far less than the 100-year time commitment of the California’s carbon market. Of those who agreed to participate, choosing between adopting and not adopting any of the three main forest management practices in the California’s carbon market:28% are likely to adopt improved forest management (IFM) practices, 24% are likely to adopt reforestation due to understocked forestlands, and 14% are likely to adopt avoided conversion. In another development, the concept of aggregation has dominated discussions in the California’s carbon market of late. It is an advocacy to include small-scale forestlands in the California’s carbon market. To aggregate, different forestland owners will combine their forestlands to participate. We find that 79% of SC forestland owners are willing to aggregate to participate. However, this research is unable to determine how much total forestland is available in SC for carbon market. We recommend future research in the State on forestland owners’participation in carbon market should consider evaluating forestland availability.展开更多
Serious soil erosion has made the eco-environment fragile in the Loess Plateau. Based on the 10-year data observed from 1989 to 1998 in the Ziwuling Survey Station in loess hilly region, the eco-environment change and...Serious soil erosion has made the eco-environment fragile in the Loess Plateau. Based on the 10-year data observed from 1989 to 1998 in the Ziwuling Survey Station in loess hilly region, the eco-environment change and soil erosion process in reclaimed forestland were studied in this paper. The results showed that the intensity of man-made soil erosion caused by forestland reclamation was 1000 times more than that of the natural erosion. From the analysis of soil physical and mechanical properties, in the 10th year after forestland was reclaimed, the clay content and physical clay content decreased 2.74 percentage point and 3.01 percentage point respectively, the >0.25mm waterstable aggregate content decreased 31.59 percentage point, the soil bulk density increased and soil shear strength decreased, all of which were easier to cause soil erosion. The correlation analysis showed that >0.25mm waterstable aggregate content was the key factor affecting soil erosion, and the secondary factors were soil coarse grain and soil shear strength. The relation between the >0.25mm waterstable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed, which showed that the first year and the seventh erosion year were the turn years of the soil erosion intensity after the forestland was reclaimed, revealed that the change of eco-environment was the main cause to accelerate soil erosion, and the worse environment caused soil erosion to be serious rapidly.展开更多
基金supported by the National Key R&D Program of China (2017YFD0600501)the Fundamental Research Funds for the Central Universities of China (TD2011-08)
文摘In Hebei Province of North China, forest was recovered with natural recruitment in plantations with large area of clear-cutting Chinese pine（Pinus tabuliformis）. This study was aimed to demonstrate the dynamic characteristics of recruits during the natural recruitment. Both plot survey and the spatial point-pattern analysis were performed. Five developmental stages of natural recruitment were selected and studied, including 1 year before and 2, 5, 8, and 11 years after clear-cutting. Different slope aspects were also included. Natural recruitment was always dominated by Chinese pine with a proportion of higher than 90%. For plots of 1 year before clear-cutting on east-and north-facing slopes, recruit densities were 7886 and 5036 stems/hm2, the average heights were 0.78（±0.85） and 1.06（±1.15） m, and the average diameters at breast height（DBH） were 3.21（±1.38） and 2.91（±1.38） cm, respectively. After clear-cutting, recruit density was initially increased, then it was gradually declined with time; however, the variation of average DBH was contrary to that of recruit density. Both of them were no longer varied between 8 and 11 years after clear-cutting. The average height of recruits continued to increase after clear-cutting. For the plots of 11 years after clear-cutting on east-and north-facing slopes, average heights of recruits reached 2.00（±1.14） and 2.24（±1.20） m, respectively. The statuses of recruits on north-facing slopes were better than those on east-facing slopes after clear-cutting. Meanwhile, recruits on east-facing slopes were always aggregated at small scales, while spatial pattern of recruits varied with time on north-facing slopes. Moreover, forest was recovered more quickly by natural recruitment than by artificial afforestation after clear-cutting. The structural diversity was higher in naturally regenerated forests than in plantations of the same age. Our results demonstrated that clear-cutting of Chinese pine plantations recovered by natural recruitment has the potential to be an effective approach for establishing multifunctional forest.
基金the National Key Technologies R&D Program of China (2006BAD03A09)the National Science Fund of China (40841001)
文摘A new model was developed to predict forestland demand of China during the years of 2010-2050 in terms of the concept of forest ecosystem services. On the basis of the relationship between forest ecosystem services and classified forest management, we hypothesized that the ecological-forest provides ecological services, whereas commercial-forest supplies wood and timber production, and the influences of the growth of population, social-economic development target, forest management methods and the technology changes on forest resources were also taken into account. The prediction reveals that the demand of total forestland of China will be 244.8, 261.2 and 362.2 million ha by the year 2010, 2020 and 2050, respectively. The results demonstrated that China will be confronted with a shortage of forest resources, especially with lack of ecological-oriented forests, in the future. It is suggested that sustainable management of forest resources must be reinforced and more attention should be drown no enhancing the service function of forest ecosystem.
文摘Activity data and emission factors are critical for estimating greenhouse gas emissions and devising effective climate change mitigation strategies. This study developed the activity data and emission factor in the Forestry and Other Land Use Change (FOLU) subsector in Malawi. The results indicate that “forestland to cropland,” and “wetland to cropland,” were the major land use changes from the year 2000 to the year 2022. The forestland steadily declined at a rate of 13,591 ha (0.5%) per annum. Similarly, grassland declined at the rate of 1651 ha (0.5%) per annum. On the other hand, cropland, wetland, and settlements steadily increased at the rate of 8228 ha (0.14%);5257 ha (0.17%);and 1941 ha (8.1%) per annum, respectively. Furthermore, the results indicate that the “grassland to forestland” changes were higher than the “forestland to grassland” changes, suggesting that forest regrowth was occurring. On the emission factor, the results interestingly indicate that there was a significant increase in carbon sequestration in the FOLU subsector from the year 2011 to 2022. Carbon sequestration increased annually by 13.66 ± 0.17 tCO<sub>2</sub> e/ha/yr (4.6%), with an uncertainty of 2.44%. Therefore, it can be concluded that there is potential for a Carbon market in Malawi.
基金National Natural Science Foundation of China No.19832060
文摘Based on data observed from 1989 to 1998 in the Ziwuling survey station, changes of soil erosion and soil physico-mechanical properties were studied after forestland reclamation. When the man-induced factors changed the eco-environment by reclaiming forestlands, the intensity of man-made soil erosion in reclaimed lands was 1,000 times more than that of natural erosion in forestlands. From the analysis of soil physical and mechanical properties, the clay content and physical clay content decreased 2.74% and 3.01% respectively, and the >0.25 mm water stable aggregate content decreased 58.7%, the soil unit weight increased and the soil shear strength decreased, all of which were easier to cause soil erosion. The results of the correlation analysis showed that the >0.25 mm water stable aggregate content was the greatest influencing factor on soil erosion, the partial correlated coefficient was 0.9728, and then were soil coarse grain and soil shear strength, the partial correlated coefficients being 0.8879 and 0.6020 respectively. The relationships between the >0.25 mm water stable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed, which showed that the first and seventh years were the turning years of the soil erosion intensity after the forestland reclamation. The degenerative eroded soil and eco-environment formed the peculiar erosion environment, which aggravated the soil erosion rapidly.
基金funded by the South Carolina Natural Resources Conservation Service(SC NRCS)with grant number 2021917
文摘Background: Carbon sequestration through recommended forest management practices is an ecosystem service that helps mitigate climate change and its impacts while generating carbon credits for forestland owners to sell in cap-and-trade programs. The California’s cap-and-trade program (California’s carbon market hereafter) allows forestland owners from any part of the contiguous United States to supply carbon credits to compliance entities. In this study, we estimate South Carolina (SC) private forestland owners’willingness to accept compensations to participate in the California’s carbon market using a contingent valuation method. Results: We estimate forestland owners’mean willingness to accept as$67 per acre per year. Our results reveal higher probability of participation of forestland owners with interests in preserving forest ecosystems than those who do not. Additionally, forestland owners who trust in information about climate change from scientists or government are willing to participate more than those who do not. Conclusions: Various factors hinder landowners’ability to participate in carbon markets. Forestland owners in SC consider legislative uncertainty and long-time commitment as the main barriers to participation in California’s carbon market. From this research, average forestland tenure in SC is 27 years, which is far less than the 100-year time commitment of the California’s carbon market. Of those who agreed to participate, choosing between adopting and not adopting any of the three main forest management practices in the California’s carbon market:28% are likely to adopt improved forest management (IFM) practices, 24% are likely to adopt reforestation due to understocked forestlands, and 14% are likely to adopt avoided conversion. In another development, the concept of aggregation has dominated discussions in the California’s carbon market of late. It is an advocacy to include small-scale forestlands in the California’s carbon market. To aggregate, different forestland owners will combine their forestlands to participate. We find that 79% of SC forestland owners are willing to aggregate to participate. However, this research is unable to determine how much total forestland is available in SC for carbon market. We recommend future research in the State on forestland owners’participation in carbon market should consider evaluating forestland availability.
文摘Serious soil erosion has made the eco-environment fragile in the Loess Plateau. Based on the 10-year data observed from 1989 to 1998 in the Ziwuling Survey Station in loess hilly region, the eco-environment change and soil erosion process in reclaimed forestland were studied in this paper. The results showed that the intensity of man-made soil erosion caused by forestland reclamation was 1000 times more than that of the natural erosion. From the analysis of soil physical and mechanical properties, in the 10th year after forestland was reclaimed, the clay content and physical clay content decreased 2.74 percentage point and 3.01 percentage point respectively, the >0.25mm waterstable aggregate content decreased 31.59 percentage point, the soil bulk density increased and soil shear strength decreased, all of which were easier to cause soil erosion. The correlation analysis showed that >0.25mm waterstable aggregate content was the key factor affecting soil erosion, and the secondary factors were soil coarse grain and soil shear strength. The relation between the >0.25mm waterstable aggregate content, the soil sheer strength and the soil erosion intensity were analyzed, which showed that the first year and the seventh erosion year were the turn years of the soil erosion intensity after the forestland was reclaimed, revealed that the change of eco-environment was the main cause to accelerate soil erosion, and the worse environment caused soil erosion to be serious rapidly.
