Soil CO2 evolution from Korean pine virgin forest at Changbai Mountain

The soil CO₂ evolution rate was measured in a virgin Korean pine forest. The results in June showed that the lowest value of evolution rate was 220 mg/(m²·h) and appeared at 6:00 a.m. The highest value was 460 mg/(m²·h) at 18:00. The rates of CO₂ evolution were related with soil temperature. On the basis of the constructed regression equation and the monthly average values of temperature, the magnitude of CO₂ evolution from Korean pine forest soil was 10.4 t/hm² during a growing season. This project was funded by the Opened Research Station of Changbai Mountain Forest Ecosystem, Chinese Academy of Sciences. Responsible editor: Zhu Hong     

非生长季长白山红松针阔叶混交林CO2通量特征

采用开路式涡度相关系统对长白山红松针阔叶混交林非生长季的CO2通量特征进行连续监测.结果显示:非生长季CO2通量变动范围为-0.3～0.5 mg·m-2s-1;秋末与初春均为显著的释放过程,虽然气温低于生物学最低温度,但在晴朗的午间,森林仍有数小时表现为碳汇的特征;在冬季覆雪状态下,森林存在微弱的相对恒定的CO2释放,在融雪阶段有一释放高峰;土壤温度高于0℃时,净生态系统碳交换量与5 cm深土壤温度呈指数相关变化.观测期间(190 d),长白山红松针阔叶混交林净碳交换量为127 g C·m-2,整体表现为一定强度的碳释放.     

Factors controlling N2O and CH4 fluxes in mixed broad-leaved/Korean pine forest of Changbai Mountain, China

Using the closed chamber technique, thein situ measurements of N₂O and CH₄ fluxes was conducted in a broad-leaved Korean pine mixed forest ecosystem in Changbai Mountain, China, from June 1994 to October 1995. The relationships between fluxes (N₂O and CH₄) and some major environmental factors (temperature, soil water content and soil available nitrogen) were studied. A significant positive correlation between N₂O emission and air/soil temperature was observed, but no significant correlation was found between N₂O emission and soil water content (SWC). This result showed that temperature was an important controlling factor of N₂O flux. There was a significant correlation between CH₄ uptake and SWC, but no significant correlation was found between CH₄ uptake and temperature. This suggested SWC was an important factor controlling CH₄ uptake. The very significant negative correlation between logarithmic N₂O flux and soil nitrate concentration, significant negative correlation between CH₄ flux and soil ammonium content were also found. This project is supported by Chinese Academy of Sciences Responsible editor: Chai Ruihai     

长白山典型阔叶红松林土壤二氧化碳排放通量

随着大气CO2浓度的升高,主要由其引起的温室效应与对生物新陈代谢的影响变得越来越显著。森林生态系统在全球碳循环中扮演着重要的角色。为了评估和理解森林土壤CO2通量及其随空气和土壤温度的季节和昼夜变化规律,我们在长白山北坡典型阔叶红松林内利用静态箱技术进行了原位观测。实验在整个生长季(6月初至9月末)昼夜进行,利用气相色谱进行气体分析。结果表明: 长白山阔叶红松林土壤是大气二氧化碳源,其CO2通量具有明显的季节和昼夜变化规律。通量的变化范围是(0.30-2.42)μmol穖-2穝-1,平均值为0.98μmol穖-2穝-1。土壤CO2排放的季节规律表明,土壤CO2通量的变化与气温和土壤温度的变化有关。CO2平均通量的最大值出现在7月((1.27±23%)μmol穖-2穝-1),最小值出现在9月((0.5±28%)μmol穖-2穝-1)。土壤CO2的昼夜波动与土壤温度变化有关,而在时间上滞后于温度的变化。森林下垫面土壤CO2通量与土壤温度显著相关,与6cm深度土层温度相关系数最大。基于气温和土壤温度计算的Q10值范围为2.09-3.40。图2表3参37。     

Soil CO_2 evolution from Korean pine virgin forest at Changbai Mountain

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Response of seedlings of different tree species to elevated C02 in Changbai Mountain

Eco-physiological responses of seedlings of eight species,Pinus koraiensis, Picea koraiensis, Larix olgensis, Populus ussuriensis, Betula platyphylla, Tilia amurensis, Traxinus mandshurica andAcer mono from broadleaved/Korean pine forest, to elevated CO₂ were studied by using open-top chambers under natural sunlight in Changbai Mountain, China in two growing seasons (1998–1999). Two concentrations of CO₂ were designed: elevated CO₂ (700 μmol·mol⁻¹) and ambient CO₂ (400 μmol·mol⁻¹). The study results showed that the height growth of the tree seedlings grown at elevated CO₂ increased by about 10%–40% compared to those grown at ambient CO₂. And the water using efficiency of seedlings also followed the same tendency. However, the responses of seedlings in transpiration and chlorophyll content to elevated CO₂ varied with tree species. The broad-leaf tree species were more sensitive to the elevated CO₂ than conifer tree species. All seedlings showed a photosynthetic acclimation to long-term elevated CO₂. Foundation item: The project was supported by National Key Basic Development of China (G1999043400) and the grant KZCX 406-4, KZCX1 SW-01 of the Chinese Academy of Sciences Biography: WANG Miao (1964-), maie, associate professor in Institute of applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

Age structure ofTilia broad-leaved Korean pine forest on northern slope of Changbai Mountain

Based on a vast of field investigation on stamps inTilia broad-leaved Korean pine forest on northern slope of Changbai Mountain, age structure of some major species were studied in this paper. The results showed that Korean pine population was composed of grouped patches with different ages. There were not strict intervals among the dominated generations, and the curve of age structure often had two or more peaks. The distribution of broad-leaved species in natural Korean pine forest was grouped or scattered, and age distribution was also uneven-aged. There existed close relation between quality of broad-leaved species and Korean pine. So, it shaped multi-storied and uneven-aged mixed forest. The model of age structure and growth demonstrated their passive correlation, but growth became slow when woods had reached old age. The study was funded by the Opened Research Station of Changbai Mountain Forest Ecosystems, the Chinese Academy of Sciences. (Reponsible Editor: Chai Rulhai)     

Factors controlling N2O and CH4 fluxes in mixedbroad-leaved/Korean pine forest of Changbai Mountain, China

IntroductionTheincreasinggreenhousegasconcentrationshavereceivedmuchattention.TwoofthesegasesthatscientistsareveryconcernedaboutareN2oandCH`,becauseoftheirrapidincreaseandtheirim-portantchemistryintheatmosphere(Bouwman199o).ThemoIecuIegIobalwarmingpotentialofN2OandCH4areabout58and2o6timesthanthatofCO2.Inaddition,atmosphericconcentrationsofN2OandCH`areincreasingatahnualratesofo.25%ando.9%respectively(HoughtonetaI1992).Forestecosystemhasbeenknownasanimportantterres-trialecosystemattheasp…     

长白山自然保护区阔叶红松林林隙更新状况

该以长白山大面积分布的阔叶红松林林隙为研究对象．系统调查了林隙形成木和林隙填充的特征，并对其主要树种的更新环境进行研究。结果表明，长白山阔叶红松林林隙多数是由1．4株形成木形成的，林隙形成木主要是红松、水曲柳、蒙古栎和紫椴；林隙填充中，紫椴和色木槭的数量最多，红松所占比例较小。不同大小林隙内填充的数量也不同，近似呈一个偏左的正态分布。现有的红松幼树一般都分布在林隙内或林隙边缘，更新环境良好。     

Response of seedlings growth ofPinus sylvestriformis to atmospheric CO2 enrichment in Changbai Mountain

The biomass and ratio of root-shoot ofPinus sylvestriformis seedlings at CO₂ concentration of 700 μL·L⁻¹ and 500 μL·L⁻¹ were measured using open-top chambers (OTCs) in Changbai Mountain during Jun. to Oct. in 1999. The results showed that doubling CO₂ concentration was benefit to seedling growth of the species (500 μL·L⁻¹ was better than 700 μL·L⁻¹) and the biomass production was increased in both above-ground and underground parts of seedlings. Carbon transformation to roots was evident as rising of CO₂ concentration. This project is supported by Chinese Academy of Sciences Responsible editor: Chai Ruihai     

Effects of elevated CO2 on net photosynthetic rate of trees in Changbai Mountain

Net photosynthetic rates (NPRs) of four species seedlings,Pinus koraiensis, Pinus sylvestriformis, Fraxinus mandshurica andPhellodendron amurense, were measured at different CO₂ concentrations and time respectively in Changbai Mountain during the growing season in 1999. The seedlings were cultivated in open-top chambers (OTCs), located outdoors and exposed to natural sunlight. The experimental objects were divided into four groups by tree species. CO₂ concentrations in chambers were kept at 500 μL·L⁻¹ and 700 μL·L⁻¹ and contrast chamber and contrast field were set. The results showed that the effects of elevated CO₂ on NPR of the trees strongly depended on tree species and time. NPRs ofPinus koreainsis andPinus sylvestriformis seedlings increased with the rising of CO₂ concentration, while that ofPhellodendron amurense andFraxinus mandshurica increased at some time and decreased at another time. This project was supported by Chinese Academy of Sciences Responsible editor: Chai Ruihai     

Effect of elevated CO2 concentration on growth course of tree seedlings in Changbai Mountain

One-year-old seedlings ofPinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 ώmol/mol CO₂ concentrations, control chamber and on open site (ambient CO₂, about 350 ώmol/mol CO₂) respectively at the Open Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, and the growth course responses of three species to elevated CO₂ and temperature during one growing season was studied from May to Oct. 1999. The results showed that increase in CO₂ concentration enhanced the growth of seedlings and the effect of 700 (ώmol/mol CO₂ was more remarkable than 500 ώmol/mol CO₂ on seedling growth. Under the condition of doubly elevated CO₂ concentration, the biomass increased by 38% in average for coniferous seedlings and 60% for broad-leaved seedlings. With continuous treatment of high CO₂ concentration, the monthly-accumulated biomass of shade-tolerantPinus koraiensis seedlings was bigger in July than in August and September, while those ofPinus sylvestriformis andPhellodendron amurense seedlings showed an increase in July and August, or did not decrese until September. During the hot August, high CO₂ concentration enhanced the growth ofPinus koraiensis seedlings by increasing temperature, but it did not show dominance in other two species. Foundation Item: This paper was supported by Chinese Academy of Sciences and the Open Research Station of Changbai Mountain Forest Ecosystem.     

Root biomass and underground C and N storage of the primitive Korean pine and broad-leaved forest and its different succession stages in Changbai Mountain, northeast China

This paper studied root biomass and underground carbon (C) and nitrogen (N) storage of a more than 200-year-old primitive Korean pine and broad-leaved forest and its two 20-and 80-year-old secondary Populus davidiana and Betula platyphylla forests in Changbai Mountain, northeast China. The results showed that with forest succession, the root biomass of 20-year-old, 80-year-old, and primitive forests was 2.437, 2.742, and 4.114 kg/m², respectively. The root C storage was 1.113, 1.323, and 2.023 kg/m², soil C storage was 11.911, 11.943, and 12.587 kg/m², and underground C storage was 13.024, 13.266, and 14.610 kg/m², respectively, while the root N storage was 0.035, 0.032, and 0.038 kg/m², soil N storage was 1.208, 1.222, and 0.915 kg/m², and underground N storage was 1.243, 1.254, and 0.955 kg/m², respectively, which indicated that along with forest succession, the forest underground became a potential “carbon sink,” whereas underground N storage did not change obviously. __________ Translated from Chinese Journal of Applied Ecology, 2005, 16(7): 1,195–1,199 [译自: 应用生态学报, 2005, 16(7): 1,195–1,199]     

Carbon fluxes and their response to environmental variables in a Dahurian larch forest ecosystem in northeast China

The Dahurian larch forest in northeast China is important due to its vastness and location within a transitional zone from boreal to temperate and at the southern distribution edge of the vast Siberian larch forest. The continuous carbon fluxes were measured from May 2004 to April 2005 in the Dahurian larch forest in Northeast China using an eddy covariance method. The results showed that the ecosystem released carbon in the dormant season from mid-October 2004 to April 2005, while it assimilated CO2 from the atmosphere in the growing season from May to September 2004. The net carbon sequestration reached its peak of 112 g.m^-2.month ^-1 in June 2004 （simplified expression of g （carbon）.m^-2.month^-1） and then gradually decreased. Annually, the larch forest was a carbon sink that sequestered carbon of 146 g-m^-2.a^-1 （simplified expression of g （carbon）.m^-2.a^-1） during the measurements. The photosynthetic process of the larch forest ecosystem was largely affected by the vapor pressure deficit （VPD） and temperature. Under humid conditions （VPD 〈 1.0 kPa）, the gross ecosystem production （GEP） increased with increasing temperature. But the net ecosystem production （NEP） showed almost no change with increasing temperature because the increment of GEP was counterbalanced by that of the ecosystem respiration. Under a dry environment （VPD 〉 1.0 kPa）, the GEP decreased with the increasing VPD at a rate of 3.0 μmol.m^-2.s^-1kPa -1 and the ecosystem respiration was also enhanced simultaneously due to the increase of air temperature, which was linearly correlated with the VPD. As a result, the net ecosystem carbon sequestration rapidly decreased with the increasing VPD at a rate of 5.2 μmol.m^-2.s-1.kPa^-1. Under humid conditions （VPD 〈 1.0 kPa）, both the GEP and NEP were obviously restricted by the low air temperature but were insensitive to the high temperature because the observed high temperature value comes within the category of the optimum range.     

Recovery of species diversity after disturbance of broad-leaved Korean pine mixed forest in Changbai Mountain

IntroductionMorerecently,Thehumanl1asshowedagreatinterestli1studiesonpatternsofchangesinspeciesdiversityduriI1gprocessofsuccession,ThedistuIbal1ceofI1umanactivitiesornaturedisastershasagreatbopactonspeciesdiversity.PlantsPeciescomprisingapost-disturbancecommunityderhefromavarietyofsources-winddispersedseed,buriedpropagulesandresproutingsurvivorsl1'l.TheirulthatecontributiontotheserialflorarenectSacomplexinteractionofinitialabundance,includingdistuthanceintCnsity,proPagatCavailability,andc…     

长白山二道白河溪流大木质物残体的初步研究

主要对长白山北坡溪流大木质物残体现存量进行了调查和研究,包括两段河道内所有大木质物残体的基径、顶径、长度、腐烂级,并在其中一段对树种尽可能进行了鉴别,以分析河岸带植被与溪流大木质物残体的关系。在调查的红松阔叶林植被带内4500 m长河道内,共发现溪流倒木425株,分属于17个树种;其中III、IV级腐烂占相当大的比重,与林地倒木II、III级腐烂占优有所不同,其原因可能与分解环境的不同有关。两段河道溪流大木质物残体的现存量为1.733 m3/100m、 10.83m3/hm2和1.709 m3/100m、 21.36 m3/hm2。处于III、IV级腐烂的溪流大木质物残体所占比重较大,与在森林中情况有所差异,可能与分解环境的不同有关。溪流大木质物残体和林地活立木的个体数量的径级分布基本上为反J型,而它们材积的径级分布均为典型的J型。溪流大木质物残体的树种组成和不同树种的材积与河岸带植被密切相关,但存在差异,分析这种差异可以深入了解河岸带植被动态。图1表4参18。     

Effects of elevated CO2 concentrations on photosynthesis, dark respiration and RuBPcase activity of three species seedlings in Changbai Mountain

Two-year-old seedlings ofPinus koraiensis, Pinus sylvestriformis andFraxinus mandshurica were treated in open-top chambers with elevated CO₂ concentrations (700 μL·L⁻¹, 500 μL·L⁻¹) and ambient CO₂ concentrations (350 μL·L⁻¹) in Changbai Mountain from June to Sept. in 1999 and 2001. The net photosynthetic rate, dark respiration rate, ribulose-1,5-bisphosphate carboxlase (RuBPcase) activity, and chlorophyll content were analyzed. The results indicated the RuBPcase activity of the three species seedlings increased at elevated CO₂ concentrations. The elevated CO₂ concentrations stimulated the net photosynthetic rates of three tree species exceptP. sylvestriformis grown under 500 μL·L⁻¹ CO₂ concentration. The dark respiration rates ofP. koraiensis andP. sylvestriformis increased under concentration of 700 μL·L⁻¹ CO₂, out that ofF. mandshurica decreased under both concentrations 700 μL·L⁻¹ and 500 μL·L⁻¹ CO₂. The seedlings ofF. mandshurica decreased in chlorophyll contents at elevated CO₂ concentrations. Foundation item: This paper was supported by the National Natural Science Foundation of China (No. 30070158). Knowledge Innovation Item of Chinese Academy of Sciences (KZCX2-406) and “Hundred Scientists” Project of Chinese Academy of Sciences. Biography: Zhou Yu-mei (1973-) Ph. Doctor, Assistant Research fellow Institute of Applied Ecology. Chinese Academy of Sciences. Shenyang 110016. P.R. China. Responsible editor: Song Funan     

Relationships between soil CO2 concentration and CO2 production, temperature, water content, and gas diffusivity: implications for field studies through sensitivity analyses

Soil CO₂ levels reflect CO₂ production and transport in soil and provide valuable information about soil CO₂ dynamics. However, extracting information from soil CO₂ profiles is often difficult because of the complexity of these profiles. In this study, we constructed a simple numerical model that simulated soil CO₂ dynamics and performed sensitivity analyses for CO₂ production rates, soil water content and temperature, and gas diffusivity at the soil surface to clarify the relationships among these parameters. Increased soil surface CO₂ flux did not always coincide with higher soil CO₂ concentrations; increased CO₂ production at shallow depths had little effect on soil CO₂ concentrations, while the opposite may be true for high levels of soil water content. Higher soil CO₂ concentration did not always coincide with greater soil surface CO₂ flux; under high soil water conditions, soil surface CO₂ flux sometimes decreased despite increased soil CO₂ concentration. Increases in soil water content did not always enhance both soil surface CO₂ flux and soil CO₂ concentration. Under high soil water conditions, increases in soil water content could lower soil surface CO₂ flux and increase soil CO₂ concentration. Increases in soil temperature resulted in greater soil surface CO₂ flux and higher soil CO₂ concentration in our simulation (extremely high temperatures were not assumed in this study). Gas diffusivity in very shallow layers did affect, albeit weakly, soil CO₂ concentration. The findings of this study may help direct future observations and aid in the interpretation of their results.     

湖南岳阳地区杨树人工林生态系统净碳交换季节动态研究

利用涡度相关法对长江流域杨树人工林CO2通量季节变化进行了研究。结果表明:CO2通量的日变化特征与杨树所处生长阶段以及光合有效辐射(PAR)有关,夜间生态系统净碳交换(NEE)与5 cm土壤温度呈指数相关,全年的生态系统净碳交换(NEE)数值波动在-2~2 mg.m-2.s-1之间。生长季NEE的变化特点为:早上7点开始生态系统整体表现为吸收CO2,到午时(11:00—13:00)NEE的值较为稳定,日落(18:30—19:00)开始生态系统呼吸作用占主导,而晚上NEE的值变化不大。CO2的最大吸收出现在早上10点左右。NEE同时表现为较为明显的季节变化,在生长季节(4-9月)NEE多为负值,生态系统整体表现为对CO2的吸收,而在非生长季表现为一定强度的碳释放,值得注意的是在2006年的6月碳固定能力弱于生长季的其他月份,原因是长期降雨导致土壤呼吸加剧和水淹的生理胁迫导致杨树呼吸作用加剧。2006年全年NEE为-579 g.m-2,说明该生态系统具有明显的碳汇功能。     

Species composition and minimum sampling area of a riparian mixed broadleaved-Korean pine forest in Changbai Mountain Nature Reserve

Riparian areas are unique although often small component of the overall watershed landscape. The structure of riparian forests along Erdaobai River on the north slope of Changbai Mountain were investigated by using field data collected from eight sampling transects perpendicular to the Erdaobai River channel. Two kinds of species-area saturation curves were used to examine the relationship between species number and minimum sampling area. The results showed that riparian gymnosperms accounted for a high proportion of all gymnosperms in the Changbai Mountain Nature Reserve while riparian ferns and angiosperms accounted for a relatively low proportion. The average minimum sampling areas of riparian forest that included 60%, 80%, and 90% of the community species pool were about 85, 185, and 328 m 2 , respectively; while those for nonriparian forest were about 275, 390, and 514 m 2 , correspondingly.