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.

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.

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.

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.

长白山主要林分物种多度分布与性状分布的关系

【目的】探究长白山地区群落物种的多度分布格局及其驱动过程,以及多度分布与性状分布之间的关系,为当地森林经营与修复策略的制定提供理论依据。【方法】以长白山不同林分类型的3块5.2 hm2(次生山杨白桦林、次生针阔混交林、原始红松紫椴林)和1块5 hm2原始阔叶红松林固定监测样地为研究对象,通过采集样地内木本个体的6个关键功能性状(叶面积、比叶面积、叶片厚度、最大树高、叶片氮含量、叶片磷含量),分析样地的物种多度分布格局、功能性状分布格局以及二者之间的关系。【结果】不同林分类型中通过统计检验的模型种类各异,但所有最优模型均为统计模型。在性状分布格局中,最大树高、比叶面积和叶磷含量在4块样地均呈现正态分布。然而,功能性状分布格局转化得到的物种分布格局模型显示,尽管部分模型通过了统计检验,但与多度分布结果拟合度不高。【结论】在长白山地区,物种多样性的形成并非主要由随机过程驱动,而是受到竞争作用的显著影响,这决定了演替过程中群落物种组成的变化情况。虽然功能性状分布与物种多度分布之间存在一定的联系,但直接通过群落水平性状分布格局推断物种多度的方法尚不准确。

胜山阔叶红松林粗木质残体空间分布格局

为探究胜山阔叶红松(Pinus koraiensis)林粗木质残体(Coarse woody debris,CWD)的形成过程及机制,采用点格局分析法对10.4 hm^(2)大型样地内不同分类的CWD的空间格局、空间关联性进行了研究。结果表明:(1)总CWD在0—7 m尺度聚集分布,7—50 m尺度随机分布。(2)腐烂等级5级CWD、倒木、伐根在所有尺度随机分布;其他CWD随尺度增大由聚集分布转为随机分布,但格局尺度不同(在2—10 m之间)。(3)大、中径级与小径级CWD在0—4 m、0—6 m尺度正相关;高腐烂等级与低腐烂等级CWD在0—5 m尺度以内正相关;枯立木与倒木在0—4 m尺度正相关;落叶松(Larix gmelinii)CWD与小径级、腐烂等级2级的红皮云杉(Picea koraiensis)CWD在0—3 m尺度正相关,与中径级、腐烂等级1、2级在13—16 m尺度负相关。胜山阔叶红松林CWD的形成是由树种特性、小尺度的个体竞争、大尺度的自然衰老、外界干扰、生境异质性等共同决定的;大、中径级对小径级CWD、先形成对后形成CWD、枯立木对倒木具有一定的正向影响,落叶松对红皮云杉CWD在小尺度有正向影响,而在稍大尺度有负面影响;在一定程度上揭示了该林型CWD的形成过程和机制。

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.

Modeling diameter distribution of the broadleaved-Korean pine mixed forest on Changbai Mountains of China

The broadleaved-Korean pine mixed forest is a native vegetation in the Changbai Mountains, northeast China. The probability density functions including the normal, negative exponential, Weibull and finite mixture distribution, were used to describe the diameter distributions of the species groups and entire forest stand. There is a strong correlation between parameters and mean DBH except the shape parameters in the mixture distribution. The diameter classes of species and entire forest stand showed not negative exponential but normal and "S" distribution. The mixture function was better than normal and Weibull to describe the model distribution. The location parameter had an effect on the estimated frequency in the first diameter class, when the estimated location parameter was bigger than the lower limit of the first diameter class.

小兴安岭五种林型早春草本植物多样性及其环境解释

早春草本层植物作为草本层动态变化的早期阶段,是森林的重要组成部分,对于维持森林生态系统功能及其多样性具有重要意义。为探究小兴安岭地区早春草本层植物对人为干扰后引起的林型改变的响应,以黑龙江凉水国家级自然保护区内的五种林型(白桦次生林(Betula platyphylla)、红松(Pinus koraiensis)人工林、落叶松(Larix gmelinii)人工林、阔叶红松择伐林以及阔叶红松林)为研究对象,分析林下早春草本层植物多样性的差异及其影响因素。结果显示:(1)研究区林下早春草本层植物共60种,隶属26科52属,林下优势种主要以银莲花(Anemone cathayensis)、东北羊角芹(Aegopodium alpestre)为主,五种林型早春草本层植物组成相似度较高;(2)五种林型不同生活史对策早春草本层植物的密度、盖度以及多样性指数均呈现显著差异;(3)土壤pH对早春生长期植物的密度、盖度及多样性指数,林下光对早春开花植物的密度和盖度以及早春展叶植物的多样性指数具有较高的解释率;(4)早春生长期植物的密度、盖度及多样性指数与土壤pH呈显著的正相关关系,其多样性指数与土壤全氮呈显著的单峰型关系;林下光与早春开花植物的密度呈显著的单峰型关系,与盖度呈显著的负相关关系;早春展叶植物的多样性指数与林下直射光和林下总光照呈显著的“U”型关系、与林下散射光呈显著的正相关关系。林型改变引起不同生活史对策的早春草本层植物的密度、盖度以及多样性的显著差异,但变化趋势不一致;土壤pH和林下光是影响林下早春草本层植物群落数量特征的主要环境因子,影响程度因草本植物自身生活史对策特性而存在差异。本研究结果为理解小兴安岭地区植物群落的生长发育特征及其影响因素提供理论依据。

人工阔叶红松混交林对土壤改良效果的研究

为了对人工阔叶红松混交林的土壤变化进行研究,以辽宁省东部山区五种典型人工阔叶红松混交林为研究对象,通过对其土壤理化性质的测定,了解其对土壤改良的效果。测定结果表明,这五种类型混交林单位面积凋落物现存量均低于红松纯林,在土壤有机质含量、碱解氮含量、在速效磷、速效钾含量方面,人工阔叶混交林均高于人工红松纯林,在土壤渗透速度和土壤理化性质方面,阔叶红松混交林均高于和好于红松纯林。

长白山阔叶红松林乔木树种幼苗组成及其年际动态

为了解阔叶红松(Pinus koraiensis)林乔木树种幼苗的组成及其年际动态,以长白山阔叶红松林25ha动态监测样地为平台,在样地内150个种子收集器周围设置了600个5m×5m幼苗样方。基于2006-2008年连续3年的幼苗样方调查数据,对乔木幼苗的树种组成、数量组成、空间分布特征、年际动态、新增和死亡幼苗组成等进行了分析。结果表明:(1)从树种组成来看,该群落乔木树种的幼苗组成种类较为丰富,共记录到21个树种,这些树种也是样地内胸径1cm以上乔木树种的主要组成成分。树种组成在年际间变化不大,但各样方间表现出极大的空间变异。(2)从数量组成来看,共记录到11,959株乔木幼苗,以水曲柳(Fraxinus mandshurica)和紫椴(Tilia amurensis)幼苗数最多,占总幼苗数的72.75%;水曲柳、紫椴和红松的幼苗数量在年际间有明显波动,其他树种年际间波动较小。(3)从新增和死亡幼苗的数量与组成来看,共记录到15个乔木树种的新增幼苗,其中紫椴、水曲柳、色木槭(Acer mono)、红松等10个树种在每次调查中都有新苗记录,新苗数量在年际间随物种和样方位置表现出明显差异。(4)对各树种的幼苗、种子和大树的组成和空间分布的比较发现,各树种的幼苗、种子和大树之间的数量组成和比例差异较大,其中紫椴、水曲柳、色木槭和假色槭(A.pseudo-sieboldianum)的幼苗、种子在整个样地内都有分布,春榆(Ulmus japonica)和怀槐(Maackia amurensis)幼苗的空间分布与种子和大树不一致,糠椴(T.mandshurica)和山丁子(Malus baccata)等的幼苗、种子和大树的个体数相对都较少,且它们的分布是一致的。

不同氮沉降水平下两种林型的主要土壤酶活性

模拟研究了天然阔叶红松林和天然次生杨桦林不同氮沉降(0、25和50kgN.hm-2.a-1)水平下土壤酶活性(纤维素酶、多酚氧化酶和蔗糖酶)的变化趋势.结果表明:氮沉降增加对土壤酶活性的作用与林分类型有关,短期施氮可以显著影响土壤酶的活性;高氮沉降降低了土壤多酚氧化酶活性,且随着多酚氧化酶活性的降低,两种林型土壤纤维素酶和蔗糖酶活性也有降低的趋势.

氮添加对长白山阔叶红松林2种树木幼苗光合生理生态特征的影响

植物的光合作用是评估全球变化背景下碳循环的重要环节。目前,氮沉降增加日益明显,作为植物生长关键因子的可利用氮将对植物的光合生理生态过程产生影响。以长白山阔叶红松林主要树种红松和紫椴的幼苗为例,通过模拟氮沉降增加(氮添加量分别为0、23、46和69 kg N hm^(-2)a^(-1))的方法,利用Li-6400光合测定系统分别测算了两个树种的最大净光合速率(A_(max))、气孔导度(G_(smax))和水分利用效率(WUE)的值,并测算了叶氮含量、叶绿素含量、比叶面积、光合氮利用效率(PNUE)的值。通过分析A_(max)随不同施氮量的变化规律,同时结合其他叶片特征参数的变化,进一步探讨植物光合随氮添加的变化原因。研究结果显示:两个树种的A_(max)值在0—46 kg N hm^(-2)a^(-1)的氮添加范围内随施氮量的增加而增大,继续增加施氮量至69 kg Nhm^(-2)a^(-1)则出现下降。叶绿素含量、G_(smax)、PNUE和比叶面积在不同的氮添加水平下的变化规律与A_(max)的一致,且均与A_(max)呈显著正相关关系。叶氮含量与A_(max)的值仅在0—46 kg N hm^(-2)a^(-1)氮添加范围内呈显著正相关。A_(max)与WUE的相关关系不显著。相同氮添加水平下,氮添加对阔叶树种紫椴各生理生态参数(A_(max)、G_(smax)、叶氮含量、比叶面积、PNUE和WUE)的促进程度高于对针叶树种红松各生理生态参数的促进程度。研究结果可为评估氮沉降增加背景下我国东北地区的碳循环提供依据。

阔叶红松林不同大小林隙土壤温度、水分、养分及微生物动态变化

对小兴安岭阔叶红松林不同大小林隙主要土壤性质和微生物数量进行测定,对其动态变化进行比较和分析。结果表明,林隙表层(0-10cm)土壤含水量比郁闭林分高。不同大小林隙土壤月平均温度呈现单峰变化。中林隙有机质平均含量(194.34g/kg)>大林隙(169.47g/kg)>小林隙(143.49g/kg)>郁闭林分(128.61g/kg)。各林隙土壤表层NH4+-N含量季节动态变化趋势基本一致。大林隙中,土壤各月平均总有效氮(铵态氮+硝态氮)含量春季最高,夏季最低。林隙的有效磷含量呈现多峰变化。8月份是速效钾吸收和淋失的高峰期。林隙土壤微生物的数量秋季最多,生长季和雨季较少。不同大小林隙土壤因子的相关分析表明,pH值与有机质、速效钾呈显著负相关,与微生物和有效磷呈显著正相关。有机质与全氮、铵态氮、硝态氮、微生物和速效钾呈现显著或极显著相关。

采伐对长白山阔叶红松林生态系统碳密度的影响

采伐对森林生态系统碳密度和固碳能力有重要的影响,且影响的程度因采伐强度和方式不同而有巨大差异。以长白山地区原始阔叶红松林在不同采伐方式、采伐强度干扰后形成的次生林为研究对象,通过对2007至2009年建立的11块1 hm2永久样地中植被层、凋落物层和土壤层碳密度在采伐前后变化特征的分析,研究了采伐强度与恢复时间对阔叶红松林生态系统碳密度的影响。结果表明:在短期内,采伐导致了植被层和土壤表层(0—20cm)碳密度值的减少,其中植被碳密度与采伐强度有显著的线性负相关关系(y=-0.9x+91.17,R2=0.626,P<0.01),而后,随着植被的恢复,生态系统碳密度增加,其中植被、土壤层碳密度呈显著线性正相关关系。根据植被碳密度与恢复时间之间的相关关系,确定以生态系统恢复、木材生产与固碳三者兼顾的合适采伐强度为30%,轮伐期为45a。

森林生态系统健康评估Ⅱ.案例实践

结合样地调查和他人对阔叶红松林生态系统相关指标的研究资料数据,利用健康距离(HD)评估法和上文建立的阔叶红松林生态系统健康评估指标体系框架,对不同人为干扰影响的长白山阔叶红松林生态系统进行系统健康的评估实践.结果按顺序依次为20%强度择伐林021<50%强度择伐林044<白桦中成林067<白桦中幼林072<红松人工林074<人工落叶松林077.

人为干扰对长白山红松针阔叶混交林粗木质残体的影响

研究人为干扰(森林采伐)对长白山红松针阔叶混交林(天然林和择伐林)粗木质残体的影响。结果表明天然林和择伐林的粗木质残体平均材积分别为78.88和41.7m3.hm-2;天然林粗木质残体大部分径级2～40cm,其中倒木、枯立木和伐桩分别占总材积的94%、5.8%和0.2%,择伐林粗木质残体大部分径级11～50cm,其中倒木、枯立木和伐桩分别占总材积的41%、4%和55%。天然林和择伐林粗木质残体的覆盖面积分别为376.2和189.3m2.hm-2;天然林和择伐林倒木腐烂级为E的倒木分别占33.5%和14%。择伐活动明显减少了森林倒木的数量。为促使采伐后的森林能维持原始林粗木质残体的结构特征,现行的森林管理措施应进行必要的调整。

受干扰长白山阔叶红松林林分结构组成特征及健康距离评估

通过样地调查对不同干扰方式产生的过伐天然林、次生白桦林和人工落叶松林等群落的结构组成进行分析和分类探讨 ,并选取能够表征结构完整性和稳定性的一些指标因子 ,利用健康距离法对长白山阔叶红松林区的森林生态系统健康进行了评估实践 ,结果按顺序依次为 :原始阔叶类 0 14 <结构转换型0 2 3<结构保留型 0 32 <结构破坏型 0 33<严重干扰类型 0 4 4 <次生白桦林 0 5 3<人工落叶松林0 6 8.以期对阔叶红松林生态系统的恢复和区域林业可持续发展提供参考 .