Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sin...Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tree layer. Our results demonstrate that these forested wetlands were generally carbon sinks in the Xiaoxing’anling, and there was obvious spatial variation in carbon storage of ecosystems along the moisture gradient.展开更多
The ornamental characters, nutritious composition, edible value and medical value of thirteen kinds of major wild fruit resources in Xiaoxing’an Mountains Region were synthetically analyzed such as Rosa spp,, Actinid...The ornamental characters, nutritious composition, edible value and medical value of thirteen kinds of major wild fruit resources in Xiaoxing’an Mountains Region were synthetically analyzed such as Rosa spp,, Actinidia spp. and so on. The results showed that the wild fruit resources in this region had important garden ornamental value, edible value and medical value. A lot of good germplasm resources and honey plant resources hadnt been effectvely protected and enough utilized. The right way of appropriate arrangement and reasonable exploitation of wild fruit resources in this region should be benefit to got rid of economic crisis early in this region.展开更多
Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of...Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of the soils in permafrost regions in the mid-latitudes and boreal regions, such as that on the westem flank of the Da Xing＇anling （Hinggan） Mountains, northeastern China. This paper gives a detailed analysis on meteorological data series from 2001 to 2010 provided by the Gen＇he Weather Station, which is located in a talik of discontinuous permafrost zone and with sparse meadow on the observation field. It is inferred that snow cover is important for the ground thermal regime in the middle Da Xing＇anling Mountains. Snow cover of 10-cm in thickness and five to six months in duration （generally November to next March） can reduce the heat loss from the ground to the atmosphere by 28%, and by 71% if the snow depth increases to 36 cm. Moreover, the occurrence of snow cover resulted in mean annual ground surface temperatures 4.7-8.2℃ higher than the mean annual air temperatures recorded at the Gen＇he Weather Station, The beginning date for stable snow cover establishment （SE date） and the initial snow depth （SDi） also had a great influences on the ground freezing process. Heavy snowfall before ground surface freeze-up could postpone and retard the freezing process in Gen＇he. As a result, the duration of ground freezing was shortened by at least 20 days and the maximum depth of frost penetration was as much as 90 cm shallower.展开更多
Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) afte...Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.展开更多
The Xiaoxing’an Mountains,located in the temperate monsoon climate zone in Northeast China,have the largest and most complete virgin Korean pine forest in Asia,which has great potential for carbon sequestration.Based...The Xiaoxing’an Mountains,located in the temperate monsoon climate zone in Northeast China,have the largest and most complete virgin Korean pine forest in Asia,which has great potential for carbon sequestration.Based on the observational data of the eddy-covariance system at Wuying National Climate Observatory in January 2015–November 2017,the CO_(2)flux in the forest ecosystem around the observatory was quantitatively studied and the distribution characteristics of the flux source area were analyzed by the Kljun model and the Agroscope Reckenholz–Tänikon footprint tool,providing references for assessing the carbon source/sink potential of the unique forest area.The results showed that the annual total carbon flux around the observatory in 2015,2016,and 2017 was−756.84,−834.73,and−629.37 gC m−2,respectively,higher than that of other forest ecosystems.The forest of the study area in the Xiaoxing’an Mountains was a strong carbon sink,with the strongest carbon fixation capacity in June and weakest in October,and the carbon flux of each month was less than zero.The flux source area under stable atmospheric conditions was larger than that under unstable conditions,and the source area was larger in the nongrowing season than in the growing season.The size of the source area was largest in winter,followed by spring,autumn,and summer.The maximum length of the source area was 1614.12 m(5639.33 m)under unstable(stable)conditions when the flux contribution rate was 90%.The peak flux contribution was located near the sensor(i.e.,within 200 m)in all seasons.The contribution of the source area from the coniferous and broadleaved mixed forest on the west side of the observatory was greater than(3.4 times)that from the Korean pine forest on the east side.展开更多
基金This project was supported fi nancially by the National Key Research and Development Program of China(2016YFA0600803)the National Natural Science Foundation of China(31370461).
文摘Wetlands play an important role in the global carbon cycle, but there are still considerable uncertainties in the estimation of wetland carbon storage and a dispute on whether wetlands are carbon sources or carbon sinks. Xiaoxing’anling are one of several concentrated distribution areas of forested wetland in China, but the carbon storage and carbon sink/source of forested wetlands in this area is unclear. We measured the ecosystem carbon storage (vegetation and soil), annual net carbon sequestration of vegetation and annual carbon emissions of soil heterotrophic respiration of five typical forested wetland types (alder swamp, white birch swamp, larch swamp, larch fen, and larch bog) distributed along a moisture gradient in this area in order to reveal the spatial variations of their carbon storage and quantitatively evaluate their position as carbon sink or source according to the net carbon balance of the ecosystems. The results show that the larch fen had high carbon storage (448.8 t ha^(−1)) (6.8% higher than the larch bog and 10.5–30.1% significantly higher than other three wetlands (P < 0.05), the white birch swamp and larch bog were medium carbon storage ecosystems (406.3 and 420.1 t ha^(−1)) (12.4–21.8% significantly higher than the other two types (P < 0.0 5), while the alder swamp and larch swamp were low in carbon storage (345.0 and 361.5 t ha^(−1), respectively). The carbon pools of the five wetlands were dominated by their soil carbon pools (88.5–94.5%), and the vegetation carbon pool was secondary (5.5–11.5%). At the same time, their ecosystem net carbon balances were positive (0.1–0.6 t ha^(−1) a^(−1)) because the annual net carbon sequestration of vegetation (4.0–4.5 t ha^(−1) a^(−1)) were higher than the annual carbon emissions of soil heterotrophic respiration (CO_(2) and CH_(4)) (3.8–4.4 t ha^(−1) a^(−1)) in four wetlands, (the alder swamp being the exception), so all four were carbon sinks while only the alder swamp was a source of carbon emissions (− 2.1 t ha^(−1) a^(−1)) due to a degraded tree layer. Our results demonstrate that these forested wetlands were generally carbon sinks in the Xiaoxing’anling, and there was obvious spatial variation in carbon storage of ecosystems along the moisture gradient.
文摘The ornamental characters, nutritious composition, edible value and medical value of thirteen kinds of major wild fruit resources in Xiaoxing’an Mountains Region were synthetically analyzed such as Rosa spp,, Actinidia spp. and so on. The results showed that the wild fruit resources in this region had important garden ornamental value, edible value and medical value. A lot of good germplasm resources and honey plant resources hadnt been effectvely protected and enough utilized. The right way of appropriate arrangement and reasonable exploitation of wild fruit resources in this region should be benefit to got rid of economic crisis early in this region.
基金supported by the National Natural Science Foundation of China (Nos. 41201066, 41401028, and J0930003/J0109)the State Key Laboratory of Frozen Soils Engineering (No. SKLFSE-ZT-14)
文摘Although many studies relevant to snow cover and permafrost have focused on alpine, arctic, and subarctic areas, there is still a lack of understanding of the influences of seasonal snow cover on the thermal regime of the soils in permafrost regions in the mid-latitudes and boreal regions, such as that on the westem flank of the Da Xing＇anling （Hinggan） Mountains, northeastern China. This paper gives a detailed analysis on meteorological data series from 2001 to 2010 provided by the Gen＇he Weather Station, which is located in a talik of discontinuous permafrost zone and with sparse meadow on the observation field. It is inferred that snow cover is important for the ground thermal regime in the middle Da Xing＇anling Mountains. Snow cover of 10-cm in thickness and five to six months in duration （generally November to next March） can reduce the heat loss from the ground to the atmosphere by 28%, and by 71% if the snow depth increases to 36 cm. Moreover, the occurrence of snow cover resulted in mean annual ground surface temperatures 4.7-8.2℃ higher than the mean annual air temperatures recorded at the Gen＇he Weather Station, The beginning date for stable snow cover establishment （SE date） and the initial snow depth （SDi） also had a great influences on the ground freezing process. Heavy snowfall before ground surface freeze-up could postpone and retard the freezing process in Gen＇he. As a result, the duration of ground freezing was shortened by at least 20 days and the maximum depth of frost penetration was as much as 90 cm shallower.
基金supported by postdoctoral grant of HeiLongJiang(Grant No.LBH-Z17002)
文摘Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.
基金Supported by the National Science and Technology Basic Resources Survey Program of China(2019FY101300)National Natural Science Foundation of China(42141016).
文摘The Xiaoxing’an Mountains,located in the temperate monsoon climate zone in Northeast China,have the largest and most complete virgin Korean pine forest in Asia,which has great potential for carbon sequestration.Based on the observational data of the eddy-covariance system at Wuying National Climate Observatory in January 2015–November 2017,the CO_(2)flux in the forest ecosystem around the observatory was quantitatively studied and the distribution characteristics of the flux source area were analyzed by the Kljun model and the Agroscope Reckenholz–Tänikon footprint tool,providing references for assessing the carbon source/sink potential of the unique forest area.The results showed that the annual total carbon flux around the observatory in 2015,2016,and 2017 was−756.84,−834.73,and−629.37 gC m−2,respectively,higher than that of other forest ecosystems.The forest of the study area in the Xiaoxing’an Mountains was a strong carbon sink,with the strongest carbon fixation capacity in June and weakest in October,and the carbon flux of each month was less than zero.The flux source area under stable atmospheric conditions was larger than that under unstable conditions,and the source area was larger in the nongrowing season than in the growing season.The size of the source area was largest in winter,followed by spring,autumn,and summer.The maximum length of the source area was 1614.12 m(5639.33 m)under unstable(stable)conditions when the flux contribution rate was 90%.The peak flux contribution was located near the sensor(i.e.,within 200 m)in all seasons.The contribution of the source area from the coniferous and broadleaved mixed forest on the west side of the observatory was greater than(3.4 times)that from the Korean pine forest on the east side.
