The restoration of forest landscape has drawn much attention since thecatastrophic fire took place on the northern slope of Great Xing'an Mountains in 1987. Forest canopydensity, which has close relation to forest...The restoration of forest landscape has drawn much attention since thecatastrophic fire took place on the northern slope of Great Xing'an Mountains in 1987. Forest canopydensity, which has close relation to forest productivity, was selected as a key factor to find howmuch the forest quality was changed 13 years after fire, and how fire severity, regeneration way andterrain factors influenced the restoration of forest canopy density, based on forest inventory datain China, and using Kendall Bivariate Correlation Analysis, and Distances Correlation Analysis. Theresults showed that fire severity which was inversely correlated with forest canopy density gradewas an initial factor among all that selected. Regeneration way which did not remarkably affectforest canopy density restoration in short period, may shorten the cycle of forest succession andpromote the forest productivity of conophorium in the future. Among the three terrain factors, theeffect of slope was the strongest, the position on slope was the second and the aspect was the last.展开更多
Afghanistan is threatened by rangeland degradation.A quantitative visual analysis of Google Earth Imagery was used to systematically locate,characterize and quantify the current extent of rangelands in Afghanistan deg...Afghanistan is threatened by rangeland degradation.A quantitative visual analysis of Google Earth Imagery was used to systematically locate,characterize and quantify the current extent of rangelands in Afghanistan degraded as a consequence of dryland agriculture.Climate data were used in conjunction with dryland agriculture locations to establish a climate envelope comprised by temperature and mean annual precipitation to create a geographical mask known to contain dryland agriculture.Within this mask we created a grid of 100 km2 cells that we analyzed individually to access dryland agriculture extent.Climatic limits to sustainable dryland agriculture and areas of high restoration priority were also assessed as was the distribution of rain-fed agriculture with respect to the location of traditional migration routes for extensive livestock producers.The extents of agriculture in Afghanistan,at both upper and lower elevations,correlated most closely with mean annual temperature(MAT) at the upper elevation limits,and with mean annual precipitation(MAP) at the lower elevation limits.In total,dryland agriculture comprised 38,980 km2 of former native rangeland.Conversion was highest in the northwestern,northern and northeastern provinces of Herat,Badghis,Faryab,Jawzjan,Sar-e-Pul,Samangan,Balkh,Baghlan,Kunduz,Takhar and Badakhshan,with the highest percentage of conversion occurring in Takhar.An MAP value of 〈400 mm is perceived by farmers as the current climatic limit to sustainable dryland agriculture across the northern regions of the country.Uder this MAP value,approximately 27,677 km2 of converted rangeland met the need for restoration priority.Climate projections indicate that Afghanistan will become warmer and drier in the coming decades.One consequence of this trend is that the MAP threshold of 〈400 mm to sustainable dryland agriculture will become obsolete in the coming decades.Restoration of currently converted rangelands is needed to restore critical grazing areas as is the adoption of prudent range management policies to prevent further land degradation and support a vital livestock industry.Food security is at stake as the conversion of rangelands to unsustainable rain-fed agriculture may leave large tracks of land unusable for either agriculture or livestock production.展开更多
The exotic Sonneratia apetala in Leizhou Peninsula, has shown outstanding fast-growing ability in restored mangrove forests, at the middle and high tide intertidal zone, with year-round fresh water input from drainage...The exotic Sonneratia apetala in Leizhou Peninsula, has shown outstanding fast-growing ability in restored mangrove forests, at the middle and high tide intertidal zone, with year-round fresh water input from drainage. By setting plot and selecting standard tree, investigation and measurement on height growth, diameter growth, biomass, productivity, and so on, were made in a S. apetala plantation at age of six at Lanbei, Fucheng, Leizhou Peninsula in May 2001. The investigating results showed that the mean annual height growth of plantation was 2.03 m and mean annual growth of diameter at breast height (DBH) was 2.35 cm. There exists a significant correlation between the diameter at ground surface (DGS) and DBH. The average biomass of a single standard tree in dry weight was 95.647 kg/m2. A ratio of above-ground biomass to under-ground biomass was 1.60. The stand biomass of unit area was 22.955 kg/m2, singletree wood volume was 88.23 dm3, and the annual wood volume productivity (PA) of the same year was 0.407. The forest energy accumulation was 424.851 MJ/m2, with annual solar energy fixing rate of 40.68 ×10-7%. It is concluded that S. apetala species had characteristics of outstanding high biomass accumulation and could be used as coastal planting tree species in southern China.展开更多
According to a Guangxi Daily report on February 26,enterprises in Guangxi cut their electricity costs by RMB 24.40 million in the first half of 2017 at a price RMB 0.027 lower per kilowatt hour for directly-purchased ...According to a Guangxi Daily report on February 26,enterprises in Guangxi cut their electricity costs by RMB 24.40 million in the first half of 2017 at a price RMB 0.027 lower per kilowatt hour for directly-purchased electricity and cut their electricity costs by more than RMB 47.60 million in the second half of 2017 at a price RMB 0.133 lower展开更多
基金This paper was supported by the National Natural Science Foundation of China (No. 30270225, 40331008)
文摘The restoration of forest landscape has drawn much attention since thecatastrophic fire took place on the northern slope of Great Xing'an Mountains in 1987. Forest canopydensity, which has close relation to forest productivity, was selected as a key factor to find howmuch the forest quality was changed 13 years after fire, and how fire severity, regeneration way andterrain factors influenced the restoration of forest canopy density, based on forest inventory datain China, and using Kendall Bivariate Correlation Analysis, and Distances Correlation Analysis. Theresults showed that fire severity which was inversely correlated with forest canopy density gradewas an initial factor among all that selected. Regeneration way which did not remarkably affectforest canopy density restoration in short period, may shorten the cycle of forest succession andpromote the forest productivity of conophorium in the future. Among the three terrain factors, theeffect of slope was the strongest, the position on slope was the second and the aspect was the last.
基金funded by the U.S.Agency for International Development (306-A-00-06-00521-00)
文摘Afghanistan is threatened by rangeland degradation.A quantitative visual analysis of Google Earth Imagery was used to systematically locate,characterize and quantify the current extent of rangelands in Afghanistan degraded as a consequence of dryland agriculture.Climate data were used in conjunction with dryland agriculture locations to establish a climate envelope comprised by temperature and mean annual precipitation to create a geographical mask known to contain dryland agriculture.Within this mask we created a grid of 100 km2 cells that we analyzed individually to access dryland agriculture extent.Climatic limits to sustainable dryland agriculture and areas of high restoration priority were also assessed as was the distribution of rain-fed agriculture with respect to the location of traditional migration routes for extensive livestock producers.The extents of agriculture in Afghanistan,at both upper and lower elevations,correlated most closely with mean annual temperature(MAT) at the upper elevation limits,and with mean annual precipitation(MAP) at the lower elevation limits.In total,dryland agriculture comprised 38,980 km2 of former native rangeland.Conversion was highest in the northwestern,northern and northeastern provinces of Herat,Badghis,Faryab,Jawzjan,Sar-e-Pul,Samangan,Balkh,Baghlan,Kunduz,Takhar and Badakhshan,with the highest percentage of conversion occurring in Takhar.An MAP value of 〈400 mm is perceived by farmers as the current climatic limit to sustainable dryland agriculture across the northern regions of the country.Uder this MAP value,approximately 27,677 km2 of converted rangeland met the need for restoration priority.Climate projections indicate that Afghanistan will become warmer and drier in the coming decades.One consequence of this trend is that the MAP threshold of 〈400 mm to sustainable dryland agriculture will become obsolete in the coming decades.Restoration of currently converted rangelands is needed to restore critical grazing areas as is the adoption of prudent range management policies to prevent further land degradation and support a vital livestock industry.Food security is at stake as the conversion of rangelands to unsustainable rain-fed agriculture may leave large tracks of land unusable for either agriculture or livestock production.
基金The paper was supported by the project of integrated mangrove management and coastal protection(IMMCP) in Leizhou Peninsula Guangdong Province.
文摘The exotic Sonneratia apetala in Leizhou Peninsula, has shown outstanding fast-growing ability in restored mangrove forests, at the middle and high tide intertidal zone, with year-round fresh water input from drainage. By setting plot and selecting standard tree, investigation and measurement on height growth, diameter growth, biomass, productivity, and so on, were made in a S. apetala plantation at age of six at Lanbei, Fucheng, Leizhou Peninsula in May 2001. The investigating results showed that the mean annual height growth of plantation was 2.03 m and mean annual growth of diameter at breast height (DBH) was 2.35 cm. There exists a significant correlation between the diameter at ground surface (DGS) and DBH. The average biomass of a single standard tree in dry weight was 95.647 kg/m2. A ratio of above-ground biomass to under-ground biomass was 1.60. The stand biomass of unit area was 22.955 kg/m2, singletree wood volume was 88.23 dm3, and the annual wood volume productivity (PA) of the same year was 0.407. The forest energy accumulation was 424.851 MJ/m2, with annual solar energy fixing rate of 40.68 ×10-7%. It is concluded that S. apetala species had characteristics of outstanding high biomass accumulation and could be used as coastal planting tree species in southern China.
文摘According to a Guangxi Daily report on February 26,enterprises in Guangxi cut their electricity costs by RMB 24.40 million in the first half of 2017 at a price RMB 0.027 lower per kilowatt hour for directly-purchased electricity and cut their electricity costs by more than RMB 47.60 million in the second half of 2017 at a price RMB 0.133 lower