Rubber(Hevea brasiliensis) plantations have been expanded rapidly in tropical regions of Southwest China and cover more than20% of land area in Xishuangbanna.Several studies have addressed changes of soil C stocks in ...Rubber(Hevea brasiliensis) plantations have been expanded rapidly in tropical regions of Southwest China and cover more than20% of land area in Xishuangbanna.Several studies have addressed changes of soil C stocks in rubber plantations;however,estimates of total ecosystem C stocks and their temporal changes in rubber plantations have been inadequately studied.This study calculated C stocks in soil,biomass,litter,and dry rubber(latex),and estimated the total ecosystem C stocks of rubber plantations in an age sequence of 3-,7-,9-,21-,27-,and 34-year-old in Xishuangbanna,Southwest China.The total C stocks in rubber plantations ranged from 150.3 to 283.7 Mg C ha^(-1),with a mean of 213.4 Mg C ha^(-1).The plantations≤9-year-old had significantly lower(P<0.05)total C stocks than those older than 9 years.Carbon stocks in soil(mass equivalent) were between 107.1–170.5 Mg C ha^(-1) and in living biomass were between 2.8–95.7 Mg C ha^(-1),representing the largest and the second largest C components in a rubber plantation ecosystem.Neglect of dry rubber C stock resulted in an underestimate of 7.8%–14.2% of the total C stock in the rubber plantations older than 9 years,which was much larger than the contribution of litter C stock(less than 2%).展开更多
The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 we...The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 were excavated.Samples from the above and belowground tree components,coarse woody debris(CWD),forest floor,and mineral soil(0-30 cm) were collected.Tree biomass was highest in the 71-year-old stand(202.8 t ha-1) and lowest in the 10-year-old stand(18.4 t ha-1).C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands,mainly due to higher soil C and N concentrations.Consequently,the total ecosystem C and N storage(tree+forest floor+CWD+soil) was positively correlated with stand age:increasing from a minimum in the 10 year old stand(18.8 t C ha-1 and 1.3 t N ha-1) to a maximum in the 71-year-old stand(201.4 t C ha-1 and 8.5 t N ha-1).The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence,while N storage in the CWD,forest floor and mineral soil showed no significant temporal trends.Our results provide important insights that will increase our understanding of C and N storage in P.densiflora stands and our ability to predict changes according to stand age in the region.展开更多
The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for thei...The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must he an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest （5, 9, 20, 30, 38, and 56 yr since planting） on the Loess Plateau to evaluate C accumulation and allocation in plants （trees, shrubs, herbages, and leaf litter） and soil （0-100 cm）. Allometric equations were developed for estimating the biomass of tree components （leaf, branch, stem without bark, bark and root） with a de- structive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ha （1 Mg = 106 g） at 5 yr to 79.44 Mg C/haat 38 yr. At the ＇old forest＇ stage （38 to 56 yr）, the amount of C in plant biomass significantly decreased （from 45.32 to 34.52 Mg C/ha） due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil （from 33.66 to 41.00 Mg C/ha）. The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil （0-20 cm） C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20-30, 30-50, 50-100, and 20-100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA05050206)
文摘Rubber(Hevea brasiliensis) plantations have been expanded rapidly in tropical regions of Southwest China and cover more than20% of land area in Xishuangbanna.Several studies have addressed changes of soil C stocks in rubber plantations;however,estimates of total ecosystem C stocks and their temporal changes in rubber plantations have been inadequately studied.This study calculated C stocks in soil,biomass,litter,and dry rubber(latex),and estimated the total ecosystem C stocks of rubber plantations in an age sequence of 3-,7-,9-,21-,27-,and 34-year-old in Xishuangbanna,Southwest China.The total C stocks in rubber plantations ranged from 150.3 to 283.7 Mg C ha^(-1),with a mean of 213.4 Mg C ha^(-1).The plantations≤9-year-old had significantly lower(P<0.05)total C stocks than those older than 9 years.Carbon stocks in soil(mass equivalent) were between 107.1–170.5 Mg C ha^(-1) and in living biomass were between 2.8–95.7 Mg C ha^(-1),representing the largest and the second largest C components in a rubber plantation ecosystem.Neglect of dry rubber C stock resulted in an underestimate of 7.8%–14.2% of the total C stock in the rubber plantations older than 9 years,which was much larger than the contribution of litter C stock(less than 2%).
基金supported by research grants from the Korea Forest Research Institute (Grant No. S110708L0101111W)National Research Foundation of Korea (Grant Nos. R01-2006-000-10863-0 and A307-K001)
文摘The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 were excavated.Samples from the above and belowground tree components,coarse woody debris(CWD),forest floor,and mineral soil(0-30 cm) were collected.Tree biomass was highest in the 71-year-old stand(202.8 t ha-1) and lowest in the 10-year-old stand(18.4 t ha-1).C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands,mainly due to higher soil C and N concentrations.Consequently,the total ecosystem C and N storage(tree+forest floor+CWD+soil) was positively correlated with stand age:increasing from a minimum in the 10 year old stand(18.8 t C ha-1 and 1.3 t N ha-1) to a maximum in the 71-year-old stand(201.4 t C ha-1 and 8.5 t N ha-1).The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence,while N storage in the CWD,forest floor and mineral soil showed no significant temporal trends.Our results provide important insights that will increase our understanding of C and N storage in P.densiflora stands and our ability to predict changes according to stand age in the region.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060300)
文摘The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must he an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest （5, 9, 20, 30, 38, and 56 yr since planting） on the Loess Plateau to evaluate C accumulation and allocation in plants （trees, shrubs, herbages, and leaf litter） and soil （0-100 cm）. Allometric equations were developed for estimating the biomass of tree components （leaf, branch, stem without bark, bark and root） with a de- structive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ha （1 Mg = 106 g） at 5 yr to 79.44 Mg C/haat 38 yr. At the ＇old forest＇ stage （38 to 56 yr）, the amount of C in plant biomass significantly decreased （from 45.32 to 34.52 Mg C/ha） due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil （from 33.66 to 41.00 Mg C/ha）. The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil （0-20 cm） C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20-30, 30-50, 50-100, and 20-100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.
