Wild fruit resources and exploitation in Xiaoxing'an Mountains

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.

Ecosystem carbon storage and sink/source of temperate forested wetlands in Xiaoxing’anling, northeast China

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.

Effect of soil physical–chemical properties on the decay of standing Pinus koraiensis in Xiaoxing'an Mountains,northeast China

We selected 18 rotten and nine healthy post- mature live standing Korean pine （Pinus koraiensis） to study the correlation between the degree of tree decay and soil physical-chemical properties in the Dialing Forest District of the Xiaoxing＇an Mountains, China. One trans- verse section of each sample tree at 40-50 cm height above the ground was tested by Resistograph to determine the inner decay status. We collected soil samples around the root zones （6-20 cm depth） of each sample tree to test the soil physical-chemical indicators including moisture con- tent, bulk density, total porosity, pH, organic matter con- tent, total and hydrolyzed N contents, total and available P contents, total and available K contents, and C/N ratio. The degree of decay of postmature Korean pine live standing trees was significantly and positively correlated with the C/N ratio （R = 0.838, P 〈 0.05）, organic matter （R = 0.615, P = 0.007） and moisture content （R = 0.543, P = 0.020） of soil around the rodt. The contents of total N, hydrolyzed N and available P sample trees were significantly in the soil under healthy greater than those underdecayed sample trees, and larger N and P contents might inhibit the decay fungi breeding in soils of pH 4.4-6.29. The optimum multiple regression equation for degree of tree decay on soil physical-chemical indicators showed that the linear correlations between the degree of decay and soil C/N ratio and pH were significant （P 〈 0.01） and the correlation was high （R2 = 0.778）. Enhancement soil C/N ratio and pH could promote the decay of tree trunks.

Short-term effects of fire disturbance on CH4 emission from forested wetlands in the Xiaoxing’an Mountains, Northeast China

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.

Meteorological Tower Observed CO_(2)Flux and Footprint in the Forest of Xiaoxing’an Mountains,Northeast China

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.

Non-use value assessment for wetland ecosystem service of Hongxing National Nature Reserve in northeast China

By the contingent value method, we studied the non-use value of wetland ecosystem service of Hongxing National Nature Reserve （HNNR） in Heilongjiang Pro- vince, northeast China. The proportion of respondents willing to pay （WTP） for protection of HNNR was 63 %. The WTP ratio was affected by geographical area, contact nature, personal preferences, and familiar degree of the respondents. The WTP value was affected by age, education level and career of the respondents. The mainly reasons for people rejecting to pay for protecting HNNR were ＂I am not familiar to HNNR＂ and ＂I had no capacity for additional spending because of low income＂. Weighted average individual WTP value was CNY 59.26 Yuan ind.^-1 year^-1 for all the respondents with WTP. The total non-use ecosystem service value of HNNR was CNY 1430 million Yuan in 2013. The heritage value was highest followed by existence value and option value. From the high ecosystem service value in HNNR, it is very important to construct nature reserve for protecting natural ecosystems and human sustainable use of natural resources.