Long-term changes in radial growth of seven tree species in the mixed broadleaf-Korean pine forest in Northeast China:Are deciduous trees favored by climate change?

The role of the temperate mixed broadleaf-Korean pine forest(BKF)in global biogeochemical cycles will depend on how the tree species community responds to climate;however,species-specific responses and vulner-abilities of common trees in BKF to extreme climates are poorly understood.Here we used dendrochronological meth-ods to assess radial growth of seven main tree species(Pinus koraiensis,Picea jezoensis,Abies nephrolepis,Fraxinus mandshurica,Phellodendron amurense,Quercus mongolica,and Ulmus davidiana)in an old-growth BKF in response to climate changes in the Xiaoxing’an Mountains and to improve predictions of changes in the tree species compo-sition.Temperature in most months and winter precipita-tion significantly negatively affected growth of P.jezoensis and A.nephrolepis,but positively impacted growth of P.koraiensis and the broadleaf species,especially F.mandshu-rica and U.davidiana.Precipitation and relative humidity in June significantly positively impacted the growth of most tree species.The positive effect of the temperature during the previous non-growing season(PNG)on growth of F.mandshurica and Q.mongolica strengthened significantly with rapid warming around 1981,while the impact of PNG temperature on the growth of P.jezoensis and A.nephrolepis changed from significantly negative to weakly negative or positive at this time.The negative response of radial growth of P.jezoensis and A.nephrolepis to precipitation during the growing season gradually weakened,and the negative response to PNG precipitation was enhanced.Among the studied species,P.koraiensis was the most resistant to drought,and U.davidiana recovered the best after extreme drought.Ulmus davidiana,P.jezoensis and A.nephrolepis were more resistant to extreme cold than the other species.Climate warming generally exacerbated the opposite growth patterns of conifer(decline)and broadleaf(increase)spe-cies.Deciduous broadleaf tree species in the old-growth BKF probably will gradually become dominant as warming continues.Species-specific growth-climate relationships should be considered in future models of biogeochemical cycles and in forestry management practices.

Soil carbon dioxide fluxes of a typical broad-leaved/Korean pine mixed forest in Changbai Mountain, China

The forest ecosystem plays an important role in the global carbon cycling. A study was conducted to evaluate soil CO2 flux and its seasonal and diurnal variation with the air and soil temperatures by using static closed chamber technique in a typical broad-leaved/Korean pine mixed forest area on the northern slope of Changbai Mountain, Jilin Province, China. The experiment was carried out through the day and night in the growing season (from June to September) in situ and sample gas was analyzed by a gas chromatograph. Results showed that the forest floor was a large net source of carbon, and soil CO2 fluxes had an obvi-ous law of seasonal and diel variation. The soil CO2 flux of broad-leaved/Korean pine mixed forest was in the range of 0.302.42 mmol穖-2穝-1 with the mean value of 0.98 mmol穖-2穝-1. An examination on the seasonal pattern of soil CO2 emission suggested that the variability in soil CO2 flux could be correlated with variations in soil temperature, and the maximum of mean CO2 flux occurred in July ((1.27±23%) mmol穖-2穝-1) and the minimum was in September ((0.50±28%) mmol穖-2穝-1). The fluctuations in diel soil CO2 flux were also correlated with changes in soil temperature; however, there existed a factor for a time lag. Soil CO2 flux from the forest floor was strongly related to soil temperature and had the highest correlation with temperature at 6-cm depth of soil. Q10 values based on air temperature and soil temperature of different soil depths were at the ranges of 2.09–3.40.

Effect of soil moisture gradient on structure of broad-leaved/Korean pine forest in Changbai Mountain

A 112 m×8 m sample pot which includes 14 sub-plots was set up along the slope in Hongshi Forestry Farm of Baihe Forestry Bureau (127°55′E, 42°30′ N), Jilin Province in August 2002. Community structure, soil moisture contents at 0–10 cm and 10–20 cm in depth, water content of litter as well as the contents of C, N and P of litter, living leaves and branches in the broad-leaved/Korean pine (Pinus korraiensis) forest were measured in each sub-plot on different slope positions. The analytical results showed that there existed an obvious soil moisture gradient along the slope: upper slope <middle slope< lower slope. The difference in soil moisture contents on different positions of slope led to a change of the stand structure of the braod-leaved/Korean pine forest. The proportion ofQuercus mongolica gradually increased with the decrease of soil moisture content and that of other major tree species in the broad-leaved/Korean pine forest gradually decreased or disappeared. The dynamic of soil moisture contents in the litter layer was as same as that in mineral soils. The decomposition rates of the litter on different slope positions were different and the dry weights of existent litter varied significantly. The soil nutrients in the litter on the lower slope was richer than that on the upper slope due to the different stand structure on the different slope positions. The moisture content and nutrient contents of soil had effects on the composition, decomposition, and the nutrient release of litter, thus affecting stands growth and stand structure and finally leading to the change of ecosystem. Key words Soil moisture gradient - nutrient - Stand structure - Broad-leaved/Korean pine forest CLC number S718.5 Document code A Foundation item: This study was supported by the NKBRSF (G1999043407-1), Tackle Key Problem of Science and technology of China (2001BA510B-07), Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-406, SCXZD0101), NKTRDP (2001BA510B-07. 2002BA516A20).Biography: WANG Yan (1970-), female, Ph. D, associate professorResponsible editor: Song Funan

Factors controlling N_2O and CH_4 fluxes in mixed broad-leaved/Korean pine forest of Changbai Mountain, China

Using the closed chamber technique, the in 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 availabIe nitrogen) were studied. A significant positive correlation between Nzo emission and air/soil temperature was observed, but no significant correIation 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.

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

Based on a vast of field investigation on stamps in Tilia broad-leaved Korean pine forest on northem 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 quantity 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.

Dynamics of nitrogen nutrition of coexisting dominant trees in mixed broad-leaved/Korean pine forest

Chemical analysis of ammonium, nitrate and total nitrogen in tree leaves and roots and anin-vivo bioassay for nitrate reductase activity (NRA) were used to monitor the seasonal variations in nitrogen assimilation among four coexisting dominant tree species, includingPinus koraiensis, Tilia amurensis, Fraxinus mandshurica andAcer mono, in a virgin mixed broad-leaved/Korean pine (Pinus koraiensis) forest. The soil study included individual horizons of L+F (0–5 cm), Ah (5–11 cm) and Aw (11–25 cm). All four species had nitrate and ammonium in their roots and leaves, and also NRA in leaves. This indicated that these coexisting species were adapted to ammonium + nitrate nutrition. A negative correlation existed between nitrate use and ammonium use. Ammonium concentration was higher than that of nitrate in tree leaves and roots, and also in soils, which indicated climax woody species had a relative preference for ammonium nutrition. There was a positive relationship between tree nitrogen nutrition use and soil nitrogen nutrient supply. Utilization of ammonium and nitrate as well as the seasonal patterns differed significantly between the species. Peaks of ammonium, nitrate, NRA and total nitrogen in one species were therefore not necessarily synchronous with peaks in other species, and which indicated a species-specific seasonal use of nitrogen. The species-specific temporal differentiation in nitrogen use might reduce the competition between co-existing species and may be an important mechanism promoting stability of virgin mixed broad-leaved//Korean pine forest.

A succession and silviculture model for the broad-leaved Korean pine forests of Changbai Mountain Area

A succession and silviculture model (ZELIG.CBA) for broad-leaved Korean pine forest of Changbai Moutain Area was developed based on the framework of ZELIG model and characteristics of Broad-leaved Korean pine forests of Changbai area. ZELIG.CBA model consists four sub-models: growth model simulating annual increment of individual tree in forest, regeneration model simulating annual establishment of different tree species, mortality model simulating annual agerelated and stress-related morality; and silviculture model simulating the forest response to different silviculture scenario. The validation of the ZELIG.CBA showed that the accuracy of the model for the forest growth was more than 95%. The succession from clear cutting site simulating showed that the ZELIG.CBA model was stable for long term simulation. And selective cutting experiment showed that the optimal scenario for broad-leaved Korean pine forests was removal volume 30% combining with 30a rotation.

NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.

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

Recovery of species diversity after catastrophic disturbance was influenced by a few factors, such as intensity of disturbance, availability of propagules, and the environmental conditions, In this paper, we examined pattems of species development after nearly 60a succession in bumed broad-leaved Korean pine mixed forest on northem slope of ChangbaiMountain. We aasessed the recovery of plant species diversity in 3 types of forests under the contition with gradient of soil moisture. Results revealed that recovery of plant species (liversity varied greatly under different environmental conditions.Species richness of secondary forests greatly related to the site condition. Secondary birch forest on mesic site had the greatest number of plant species and the following was poplar-birch forest and larch-birch forest.Most of characteristic taxa couldbe found in birch forest after 60a succession. For larch-birch forest on hydra site, most of climax species were still not able to invade, so it had the lowest species diversity.

Canopy gap characteristics and its influence on the regeneration of broad-leaved Korean pine forests in Changbai Mountain

With the concem of regcneration, characteristics of canopy gaps in broad-leaved Korean pine forest were studied.The areas of actual gap, expanded gap and maximum gap were analyzed respectively. The species composition, number, origin,decayed class and sizes of gap makers were studied comprehensively. The comparative studies of regencration inside and outside of canopy gap showed that the density of regeneration inside canopy gaps was 30% higher than that outside canopy gaps. The specific species regeneration response to canopy gap varied greatly. Pinus koraiensis, Picea jezoensis Frarinlis nla)ldshurica, JItghI)ls )nalJholu-i`a and Acer mono generally did not response to canopy gap disturbance. The Regeneration Importantce Valuc (RIV) of Abies nephrolepis, Ulmus Japonica increased with canopy gap disturbance. RIV of Tilia amurensis, Acer madshurica and Ulmus laciniata decreased with canopy gap disturbance. Canopy gap disturbance was not strong enough to result in the regeneration of some rpecies of shade intolerance such as Larix olgensis, Betula platyphylla.

Meteorological control on CO_2 flux above broad-leaved Korean pine mixed forest in Changbai Mountains

The impacts of temperature, photosynthetic active radiation (PAR) and vapor pressure deficit (VPD) on CO2 flux above broad-leaved Korean pine mixed forest in the Changbai Mountains were studied based on eddy covariance and meteorological factors measurements.The results showed that, daytime CO2 flux was mainly controlled by PAR and they fit Michaelis-Menten equation. Meanwhile VPD also had an influence on the daytime flux. Drier air reduced the CO2 assimilation of the ecosystem, the drier the air, the more the reduction of the assimilation. And the forest was more sensitive to VPD in June than that in July and August. The respiration of the ecosystem was mainly controlled by soil temperature and they fit exponential equation. It was found that this relationship was also correlated with seasons; respiration from April to July was higher than that from August to November under the same temperature. Daily net carbon exchange of the ecosystem and the daily mean air temperature fit exponential equation. It was also found that seasonal trend of net carbon exchange was the result of comprehensive impacts of temperature and PAR and so on. These resulted in the biggest CO2 uptake in June and those in July and August were next. Annual carbon uptake of the forest ecosystem in 2003 was -184 gC. m-2.

Estimate of productivity in ecosystem of the broad-leaved Korean pine mixed forest in Changbai Mountain

We measured soil, stem and branch respiration of trees and shrubs, foliage photosynthesis and respiration in ecosystem of the needle and broad-leaved Korean pine forest in Changbai Mountain by LI-6400 CO2 analysis system. Measurement of forest microclimate was conducted simultaneously and a model was found for the relationship of soil, stem, leaf and climate factors. CO2 flux of different components in ecosystem of the broad-leaved Korean pine forest was estimated based on vegetation characteristics. The net ecosystem exchange was measured by eddy covariance technique. And we studied the effect of temperature and photosynthetic active radiation on ecosystem CO2 flux. Through analysis we found that the net ecosystem exchange was affected mainly by soil respiration and leaf photosynthesis. Annual net ecosystem exchange ranged from a minimum of about -4.671μmol·m-2·s-1 to a maximum of 13.80μmol·m-2·s-1, mean net ecosystem exchange of CO2 flux was -2.0μmol·m-2·s-1 and 3.9μmol·m-2·s-1 in winter and summer respectively (mean value during 24 h). Primary productivity of tree, shrub and herbage contributed about 89.7%, 3.5% and 6.8% to the gross primary productivity of the broad-leaved Korean pine forest respectively. Soil respiration contributed about 69.7% CO2 to the broad-leaved Korean pine forest ecosystem, comprising about 15.2% from tree leaves and 15.1% from branches. The net ecosystem exchange in growing season and non-growing season contributed 56.8% and 43.2% to the annual CO2 efflux respectively. The ratio of autotrophic respiration to gross primary productivity (Ra:GPP) was 0.52 (NPP:GPP=0.48). Annual carbon accumulation underground accounted for 52% of the gross primary productivity, and soil respiration contributed 60% to gross primary productivity. The NPP of the needle and broad-leaved Korean pine forest was 769.3 gC·m-2·a-1. The net ecosystem exchange of this forest ecosystem (NEE) was 229.51 gC·m-2·a-1. The NEE of this forest ecosystem acquired by eddy covariance technique was lower than chamber estimates by 19.8%.

长白山针阔混交林不同演替阶段的昆虫多样性

昆虫多样性变化对生态系统健康有重要的指示作用,为研究昆虫群落变化与生境演替之间的关系,本研究采用网捕、灯诱和诱捕法系统调查了长白山针阔混交林不同演替阶段(次生白桦林、次生针阔混交林、原始阔叶红松林)昆虫群落的组成和多样性,分析了昆虫在森林演替过程中的规律及与植被群落之间的关系。系统调查共采集昆虫标本8183头,隶属于14个目699种,其中鳞翅目和鞘翅目是主要优势类群。次生针阔混交林昆虫的个体数量最多,原始阔叶红松林中物种数最多。不同演替阶段昆虫群落的物种数和个体数差异不显著,但次生针阔混交林、原始阔叶红松林的Fisher’sα指数显著高于次生白桦林。目水平上的昆虫多样性未表现出显著性差异。昆虫多样性在森林演替过程中和草本植物多样性的变化趋势相同;由于食性和生境选择的不同,森林演替过程中鳞翅目昆虫多样性逐渐升高,而鞘翅目多样性逐渐降低。

小兴安岭红松林土壤酶活性与土壤理化性质的时空变化

采用土壤学常规实验研究了小兴安岭原始红松林和人工红松林土壤酶活性和土壤理化性质的时空变化及两者之间的相关性。结果表明:土壤酶活性及土壤理化性质各项指标整体上表现为9月份最高,表层土壤(0<h≤5 cm)高于下层土壤(5 cm<h≤20 cm),且差异显著。原始红松林土壤葡萄糖苷酶、酸性磷酸酶、过氧化氢酶活性低于人工红松林,土壤多酚氧化酶和土壤脲酶活性却相反;土壤理化性质各项指标以原始红松林较高,土壤理化性质和土壤酶活之间具有显著相关性。

辽东山区原始红松林土壤理化性质及其与土壤有机碳的相关性分析

【目的】分析我国辽东山区原始红松林土壤理化性质的空间分布格局,揭示原始红松林土壤有机碳与土壤理化性质的相互关系。【方法】采用剖面法和经典的土壤理化性质测定方法,以辽东山区白石砬子森林生态站原始红松林作为对象,按照原始红松林内红松、其他针叶树种以及阔叶树种组成比例的不同,将其划分为原始红松林Ⅰ(6红松4阔叶)、原始红松林Ⅱ(3红松2其他针叶5阔叶)和原始红松林Ⅲ(3红松7阔叶)3种类型,测定了3种原始红松林土壤理化性质的垂直分布特征,并分析红松林土壤有机碳与其他土壤理化性质(土壤体积质量、全氮、水解性氮、全磷、速效磷、全钾和pH值)的相关性。【结果】不同树种组成的原始红松林的土壤理化性质之间存在明显差异,其中原始红松林Ⅲ土壤的有机碳、全磷和速效磷平均含量最高,原始红松林Ⅰ土壤的全氮和全钾平均含量最高,原始红松林Ⅱ土壤的水解性氮、体积质量和pH值平均值最高。不同树种组成的原始红松林土壤有机碳与全氮、水解性氮、全磷、速效磷等4个土壤养分因子均呈显著正相关关系,与全钾呈显著负相关关系,其中相关性最高的是土壤全氮。另外,土壤有机碳还与土壤体积质量和pH值呈显著负相关关系。【结论】辽东山区不同树种组成的原始红松林土壤理化性质存在明显差异,但均与土壤有机碳表现出较高的相关性。

小兴安岭原始红松林降雨截留观测及分段模拟

以小兴安岭原始红松林为研究对象,通过119场降雨的观测,对原始红松林的降雨截留再分配进行系统研究。结果表明:1)研究期内小兴安岭原始红松林的穿透降雨量、树干径流量和冠层截留量依次为636.04、14.62、177.84 mm,分别占林外降雨量的76.77%、1.76%、21.47%;2)原始红松林的穿透雨率、林冠截留率与降雨量之间均呈对数关系(P<0.01),而穿透雨量、林冠截留量与降雨量之间均呈线性相关关系(P<0.01);3)当降雨量>0.5mm时,原始红松林开始产生树干径流,且树干径流量和树干径流率均与降雨量呈正相关关系(P<0.01);4)在原始红松林水文过程中,通过变异系数比较可知,树干径流的变异性最大,穿透雨变异性最小;5)分段模拟和分类回归树的结果显示,林冠截留与降雨量拟合曲线的分割点为2.3和9.8 mm,且与整体回归模型相比较,分雨量段的林冠截留预测模型精度高,更符合林冠截留的生态水文过程。

小兴安岭原始阔叶红松林和枫桦次生林土壤有机碳库比较研究

土壤有机碳含量是全球生态系统碳储量变化的重要指标之一,本研究以空间替代时间序列的方法,分别选取了小兴安岭地区原始阔叶红松林和枫桦次生林并测定土壤有机碳库、土壤全氮含量、土壤微生物量碳及土壤相关理化性质,结果表明,土壤有机碳含量（SOC）、土壤全氮含量（TN）、土壤微生物量碳（MBC）、土壤含水率等指标随着土壤层的深度增加而逐渐减少最后趋于稳定,而土壤容重随着土壤层的加深而增大。在原始林中0~10和10~20 cm层的SOC、TN含量差异不显著,而次生林则差异显著。原始阔叶红松林和枫桦次生林的土壤有机碳密度（SOCD）分别为21.46和21.3 kg·m-2,差异不显著。原始林和次生林的平均有机碳含量分别为35.79,28.6 g·kg-1,土壤全氮含量分别为2.86,1.83 g·kg-1,枫桦次生林MBC与SOC的线性相关性高于原始林。结果表明原始林土壤肥力高于次生林,在今后次生林的管理中应适当混栽针叶树种,原始林中应适当间伐使地下碳储量增加。

伊春市朗乡自然保护区原始红松林的结构特征分析

阔叶红松林是分布在北温带的多物种、多层次、多价值、多效益的一种森林类型,具有物种丰富、结构复杂、生物量高、自我维持能力强的特点,是被普遍认同的高价值、高产量的森林资源。在伊春市朗乡林业局东折棱河林场的原始红松林中选取8个30 m×30 m的标准地进行调查,分析其林分结构组成,树种空间分布格局和更新情况等。结果认为,东折棱河林场原始红松林的主要伴生阔叶树种为蒙古栎、色木槭等,成林红松多为随机分布,原始红松林下的红松更新情况较差。

原始红松林土壤理化及微生物碳代谢特征对生长季动态的响应

【目的】明确原始红松林内土壤微生物群落对碳源的利用、土壤理化性质的季节变化规律及差异机制,探讨原始红松林土壤理化及生物学特征对气象因子季节动态的响应。【方法】以小兴安岭典型的原始阔叶红松林为研究对象,分别于2015年5—10月生长季内采集0~10 cm和≥10~20 cm的表层土壤样品。采用Biolog-ECO微平板检测法和土壤理化性质的常规测定方法测定红松林内土壤微生物功能多样性及土壤理化指标。【结果】(1)研究样地的多项土壤理化指标在月份间差异显著。(2)在整个生长季内平均颜色变化率(AWCD)的变化趋势基本一致,均随着培养时间的延长而逐渐升高,培养168 h以后,AWCD增加幅度逐渐减弱;AWCD值和多样性指数在月份间差异显著;土壤微生物群落的代谢活性表现出明显的季节差异,并呈现一定的规律性,6月显著高于其他月份(P<0.05)。(3)氨基酸类、多聚物类、碳水化合物类碳源是红松林土壤微生物群落利用的主要优势碳源类型;通过主成分分析(PCA)、聚类分析可将土壤微生物群落碳源代谢特征大致分为3簇,即5—6月、7月、8—10月;土壤微生物利用碳水化合物类、氨基酸类、羧酸类碳源的变化对季节最为敏感。(4)通过相关性分析发现,AWCD值和多样性指数与速效磷、速效钾、含水量和有效氮之间存在显著或极显著相关性;分类变异分析发现土壤理化性质变化是引起微生物功能多样性发生季节性变化的主要因子,其中含水量、速效磷的解释度分别为12.76%和30.71%。【结论】原始阔叶红松林土壤理化及微生物功能碳代谢特征具有显著的生长季动态变化,月降水总量变化的影响最为重要。