低温胁迫下红松与西伯利亚红松光合与气孔特性

红松与西伯利亚红松均为寒温带著名的成林树种,具有较强的耐寒性,与红松相比,西伯利亚红松具有更强的耐寒性。为探究低温胁迫下两树种的生理响应机制及抗寒生理机理,本研究以5年生的红松与西伯利亚红松幼苗为材料,对其进行低温处理,3个胁迫温度(0℃、-20℃和-40℃)和3个胁迫时间(6、24和48 h),20℃为对照,研究低温胁迫下红松与西伯利亚红松的光合特性和气孔特性。T检验和方差分析结果表明,各光合指标和气孔密度在红松与西伯利亚红松中的差异显著(P<0.05),低温及低温胁迫时间对红松与西伯利亚红松各光合指标具有极显著影响(P<0.01),低温对红松与西伯利亚红松的气孔开度与气孔面积具有极显著影响(P<0.01)。胁迫前(20℃)和0℃低温胁迫下,红松中的净光合速率、气孔导度和蒸腾速率均显著高于西伯利亚红松,但在-20℃条件下胁迫6 h,西伯利亚红松各光合测定指标显著高于红松。随着温度的降低与胁迫时间的延长,两树种的各光合指标均呈下降趋势。红松中的气孔密度显著高于西伯利亚红松,胁迫前(20℃),红松与西伯利亚红松的气孔均为椭圆形,随着温度的降低,两树种的气孔开度和气孔面积显著减小。     

水分条件对红松和西伯利亚红松针叶脯氨酸与叶绿素含量的影响

以盆栽3年生红松和西伯利亚红松为材料,设置4种水分条件,土壤含水量分别为：29％～31％（C）, 22%～24%（L）, 15%～17%（M）和渍水组（W）,研究不同水分条件下红松和西伯利亚红松当年生针叶和往年生针叶的脯氨酸含量和叶绿素含量变化。结果表明：1）脯氨酸含量在不同叶龄和不同树种之间存在差异。红松当年生针叶叶绿素含量高于往年生针叶,而西伯利亚红松则相反。总体上西伯利亚红松的脯氨酸含量高于红松;2）2树种在渍水条件下脯氨酸含量大量积累,红松在处理后一个月即出现胁迫反应,早于西伯利亚红松。土壤含水量在 15%～17%时已对2种红松的往年生针叶产生胁迫,但对红松的胁迫程度大于西伯利亚红松;3）叶绿素积累与2种红松的耐水分胁迫能力相关性不大;4）西伯利亚红松的水分适应范围大于红松;2种红松的当年生针叶的耐水分胁迫能力均大于往年生针叶。     

大兴安岭林区引种西伯利亚红松研究进展

西伯利亚红松(Pinus sibirica)是寒温带森林主要成林树种, 具有较强的区域适应性和应用价值, 已成为大兴安岭林区的重要引种树种。文章基于植物引种程序, 从西伯利亚红松引种准备、引种造林试验、引种应用等方面综述了国内外最新研究动态, 并分析当前该树种引种研究存在的不足, 从不同尺度对西伯利亚红松未来可能研究方向进行展望, 以期为西伯利亚红松在大兴安岭林区的推广种植和森林生态系统可持续发展提供科学参考。     

西伯利亚红松(Pinus sibirica Du Tour)在大兴安岭的存在

1981年以来赵光仪等以营养器官形态解剖特征,结合生态地理分析,连续报道了西伯利亚红松 Pinus sibirica在大兴安岭的存在,引起争议。1989年秋,我们于大兴安岭满归林业局采到了争议松树的球果,经同主产区的西伯利亚红松及红松P．koraiensis标本对照研究,再次认定大兴安岭争议松树确属西伯利亚红松。从而最终证实了吴中伦先生25年前关于西伯利亚红松存在于大兴安岭的预见,纠正了所谓“漠河红松”30余年的误称。根据10年来调查研究结果绘出了大兴安岭及其毗邻地区红松、西伯利亚红松分布略图,显示了两种松树生态地理学特征的深刻差异。     

中国松属一新种

在我国大兴安岭西北部,阿龙山、满归和敖鲁古雅等地,鄂温克族猎民中长期有信奉"昂特"(Onter)红松之传统,"昂特"为鄂温克语,意为"神树",据猎民称,此树既不是红松、(Pinus koraiensi),又非偃松(P.pumila)。几年来,经调查研究,发现其分布区域较广阔,但现存数量极少,甚罕见,其形态虽与西伯利亚红松(P.sibirica)相近,并与偃松相似,但亦有其独立特征,应为一新种。     

长白山温带森林不同演替阶段群落结构特征

原始阔叶红松林是长白山西部地区的地带性顶级植被类型, 经采伐干扰或火烧破坏后形成大面积次生林。参照CTFS (Centre for Tropical Forest Science)样地建设技术规范, 于2005~2007年, 在长白山地区典型次生杨桦林、次生针阔混交林和椴树红松林内各建立了5.2 hm²固定监测样地。调查并鉴定了样地内胸径大于1 cm的木本植物, 初步分析了森林监测样地的群落组成和种群结构, 并应用双相关函数g(r)分析了样地内5个优势树种的空间分布。结果表明: 次生杨桦林样地共监测木本植物32种, 20 949株活个体, 隶属于13科21属。次生针阔混交林样地共监测木本植物31个种, 14 725株活个体, 隶属于12科20属。椴树红松林样地共监测木本植物20个种, 12 062株活个体, 隶属于11科13属。次生杨桦林、次生针阔混交林及椴树红松林中胸径大于1 cm的木本植物胸高断面积之和分别为24.74、32.07和56.64 m²·hm^-2。紫椴(Tilia amurensis)是长白山针阔混交林带的重要组成树种, 其重要值、胸高断面积在3个森林监测样地内均居于前列。白桦(Betula platyphylla)、山杨(Populus daviana)重要值和胸高断面积在次生杨桦林内均处于优势地位, 而在椴树红松林内优势地位为红松(Pinus koraiensis)等顶级树种所取代。次生杨桦林和次生针阔混交林中, 红松、色木槭(Acer mono)、臭松(Abies nephrolepis)、鱼鳞松(Picea jezoensis)和紫椴的径级结构均呈倒J型分布; 而椴树红松林内, 红松和紫椴的径级结构则呈单峰分布, 色木槭、臭松和鱼鳞松呈倒J型分布。g(r)分析表明长白山森林监测样地内5个优势树种的空间格局以聚集分布为主, 聚集强度在同种个体周围(r≤4 m)达到最大, 随着距离增加, 聚集强度逐渐减小。次生林中树种空间格局的环境解释量较高, 而椴树红松林中环境因子对树种空间分布的解释能力较差。     

不同径级的西伯利亚红松树干液流及蒸腾耗水特征的差异

基于热扩散技术,采用TDP法连续监测了新疆喀纳斯国家自然保护区内不同径级西伯利亚红松的树干液流,分析其在生长季内(6~9月)的液流变化及蒸腾耗水特性,为阐明喀纳斯保护区优势树种水分循环机理,以及理解区域尺度上森林生态系统水分循环及其过程应对未来气候变化的响应机制提供依据。结果显示:(1)不同径级西伯利亚红松在晴、阴、雨3种天气条件下的树干液流日动态变化均呈昼高夜低的多峰型曲线,但变化频率和变化幅度差异明显,日最大液流值的排序为晴天阴天雨天。(2)树干液流的发生较光合有效辐射的变化存在明显的滞后效应,不同径级西伯利亚红松的最大液流峰值滞后时间在30~207min。(3)西伯利亚红松的月平均树干液流的大小顺序为7月8月9月6月,且相同径级树干阳生面的液流速率均大于阴生面。(4)西伯利亚红松全株的蒸腾耗水量为7月份的最大,其值占整个生长季的61.8%;且大径级阳生面的蒸腾耗水总量(6 716.79g)和阴生面蒸腾耗水总量(4 649.08g)分别是相应小径级阳生面和阴生面的2.00和2.45倍。(5)气温、空气相对湿度和光合有效辐射是影响西伯利亚树干液流的主要因素,同时0~5cm和20~30cm土壤温度对其影响也较大。研究表明,西伯利亚红松在生长过程中,大径级树干的液流和蒸腾耗水量大于小径级,主要发生部位为树干的阳生面,且在7月份的变化最明显。     

气候变化对我国红松林地理分布影响的研究

在红松林地理分布规律研究的基础上,应用地理信息系统ＩＤＲＩＳＩ和专门计算机软件——生态信息系统ＧＲＥＥＮ,找出适宜红松林分布的地理气候参数区间,并以此确定了红松林适宜分布区,在此基础上,根据全球气候预测模型ＧＣＭｓ预测的２０３０年的气候变化结果,就气候变化对我国红松林地理分布的可能影响进行了预测。结果表明：到２０３０年,因气候变化的影响,我国适宜红松分布的面积将有所增加,但增加幅度不大,仅占当前气候条件下适宜红松分布面积的３．４％,局部地区变化的情况是：在黑龙江省的西北部适宜红松分布的面积将有所增加;在辽宁省的西南部适宜红松分布的面积将有所减少。红松林现实分布区的南界将向北移动０．１～０．６个纬度,北界将向北扩展０．３～０．５个纬度,黑龙江省境内的红松林分布区的西界将向西扩展０．１～０．５个经度。我国适宜红松分布的面积将由当前气候条件下的２．９×１０７ｈｍ２,增加到３．０×１０７ｈｍ２。就当前气候变化影响预测中存在的问题及未来研究的方向进行了讨论。     

择伐对阔叶红松林主要组成树种种内、种间竞争的影响

以择伐37 年后的阔叶红松林为对象,研究择伐对林内主要树种种内、种间竞争的影响.结果表明：择伐对阔叶红松林主要树种的种群结构、分布格局和竞争指数均产生了极显著影响.各树种的竞争指数变化值与其耐荫性指数存在极显著负相关关系(r=-0.8821).种内竞争强度与聚集强度、个体数呈极显著线性关系,择伐区内枫桦、紫椴等阳性树种的聚集强度最大,种内竞争强度远大于种间竞争,有利于树种之间的共存.择伐降低了红松对其伴生树种的竞争,而阳性树种对其他树种的竞争压力有所上升.择伐37 年后,红松所受的竞争压力变化较小,有利于红松的稳定生长;由于自疏作用,枫桦、紫椴的优势度将有所下降;冷杉所受的竞争压力有所减弱,有利于其种群数量的恢复.     

阿尔泰山萨彦岭4种优势树种径向生长对气候因子的响应

气候变化深刻地影响森林树木的生长,而树种对气候变化敏感度的差异可能影响了气候变化下的森林生态系统响应。因此,研究优势树种间生长对气候变化的敏感度差异,对正确认识气候变化下林分生长动态及分布格局十分重要。基于树木年代学的方法,研究了阿尔泰山萨彦岭西伯利亚落叶松（Larix sibirica）、西伯利亚红松（Pinus sibirica）、西伯利亚冷杉（Abies sibirica）以及西伯利亚云杉（Picea obovata）4种优势树种的径向生长-气候关系。结果显示：（1）西伯利亚冷杉径向生长与上一年10-11月、当年1-9月的干旱指数、2-4月的降水显著正相关,与1月的平均温和最高温呈显著负相关关系,与当年4、6月份的水汽压正相关;（2）西伯利亚落叶松径向生长与上一年8月和当年8月的平均温、最高温以及当年8月的最低温显著负相关,而与当年6月的最低温则正相关,与8月份的水汽压显著负相关;（3）西伯利亚红松径向生长与3月降水、7月最低温、上一年10月的水汽压显著正相关;（4）西伯利亚云杉径向生长与6月平均温、最高温、水汽压正相关,与上一年10-11月、当年2-4月和9月的干旱指数正相关,同时与3、4月的降水量显著正相关。西伯利亚冷杉和西伯利亚云杉、西伯利亚云杉和西伯利亚落叶松、西伯利亚云杉和西伯利亚红松对于特定气候因子表现出相似的响应结果,与年表间相关性的结果一致。但差异也是明显的,西伯利亚冷杉和西伯利亚云杉对区域水分变化敏感,而西伯利亚落叶松和西伯利亚红松主要对区域温度变化敏感。综上所述,气候变化下,该区域优势树种对气候变化响应的差异可能导致区域林分动态和格局的改变,因此,多树种径向生长-气候关系研究有助于正确反映森林动态。研究结果可以为区域森林管理与生态保护工作提供理论依据。     

Growth decline linked to warming-induced water limitation in hemi-boreal forests

Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.     

Understanding 3D structural complexity of individual Scots pine trees with different management history

Tree functional traits together with processes such as forest regeneration, growth, and mortality affect forest and tree structure. Forest management inherently impacts these processes. Moreover, forest structure, biodiversity, resilience, and carbon uptake can be sustained and enhanced with forest management activities. To assess structural complexity of individual trees, comprehensive and quantitative measures are needed, and they are often lacking for current forest management practices. Here, we utilized 3D information from individual Scots pine (Pinus sylvestris L.) trees obtained with terrestrial laser scanning to, first, assess effects of forest management on structural complexity of individual trees and, second, understand relationship between several tree attributes and structural complexity. We studied structural complexity of individual trees represented by a single scale‐independent metric called “box dimension.” This study aimed at identifying drivers affecting structural complexity of individual Scots pine trees in boreal forest conditions. The results showed that thinning increased structural complexity of individual Scots pine trees. Furthermore, we found a relationship between structural complexity and stem and crown size and shape as well as tree growth. Thus, it can be concluded that forest management affected structural complexity of individual Scots pine trees in managed boreal forests, and stem, crown, and growth attributes were identified as drivers of it.     

Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe

Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland‐dominated forest‐steppe area and small forest patches in a grassland‐dominated area. We found increasing climate sensitivity and decreasing first‐order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland‐dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland‐dominated area, the increase was much greater than in the forest‐dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure.     

A Changing Number of Alternative States in the Boreal Biome: Reproducibility Risks of Replacing Remote Sensing Products

Publicly available remote sensing products have boosted science in many ways. The openness of these data sources suggests high reproducibility. However, as we show here, results may be specific to versions of the data products that can become unavailable as new versions are posted. We focus on remotely-sensed tree cover. Recent studies have used this public resource to detect multi-modality in tree cover in the tropical and boreal biomes. Such patterns suggest alternative stable states separated by critical tipping points. This has important implications for the potential response of these ecosystems to global climate change. For the boreal region, four distinct ecosystem states (i.e., treeless, sparse and dense woodland, and boreal forest) were previously identified by using the Collection 3 data of MODIS Vegetation Continuous Fields (VCF). Since then, the MODIS VCF product has been updated to Collection 5; and a Landsat VCF product of global tree cover at a fine spatial resolution of 30 meters has been developed. Here we compare these different remote-sensing products of tree cover to show that identification of alternative stable states in the boreal biome partly depends on the data source used. The updated MODIS data and the newer Landsat data consistently demonstrate three distinct modes around similar tree-cover values. Our analysis suggests that the boreal region has three modes: one sparsely vegetated state (treeless), one distinct ‘savanna-like’ state and one forest state, which could be alternative stable states. Our analysis illustrates that qualitative outcomes of studies may change fundamentally as new versions of remote sensing products are used. Scientific reproducibility thus requires that old versions remain publicly available.     

黑龙江省大兴安岭林区火烧迹地森林更新及其影响因子

林火干扰是大兴安岭森林更新的影响因子之一,研究火烧迹地森林更新的影响因子(立地条件、火前植被、火干扰特征)对理解生态系统的结构、功能和火后演替轨迹具有重要意义。选取呼中及新林林业局55个代表性火烧样地,利用增强回归树分析法分析了火烧迹地森林更新的影响因素。结果表明:(1)立地条件是影响针、阔叶树更新苗密度的主要因素;海拔对针叶树更新苗密度的影响最大;坡度对阔叶树更新苗密度影响最大;(2)距上次火烧时间对针叶树更新苗比重影响最大,其次是林型;(3)中度林火干扰后森林更新状况好于轻度和重度火烧迹地。根据火烧迹地森林更新调查分析可知:林型影响火后演替模式,火前为针叶树或阔叶树纯林,火后易发生自我更新(火后树种更新组成与火前林型相同),而针阔混交林在火干扰影响下易于发生序列演替(火后初期以早期演替树种更新为主)。     

A Study on the Quantitative Relationship between Pinus Pollen in Surface Sample and Pinus Vegetation

Based on percentages of Pinus pollen in surface samples and that of Pinto vegetation, the data indicates that, in Pinus forest its pollen is more then 90% of total tree pollen, while in non-pine area it is usually less than 30%. The factors influencing dispersal of the Pinus pollen, besides production, are air currents and landform. In the Pinus mixed forest the behavior of associate tree pollen has great effect on statistical result of Pin,ts pollen percentage. To estimate quantitatively the relationship between Pinus plant and its pollen, two curves are fitted by powet regression. Although Pinus pollen has great productivity and complex dispersal characteristics, the relationships between Pinus trees and Pinus pollen shown in our data are relatively consistant.     

Disentangling the effects of area, energy and habitat heterogeneity on boreal forest bird species richness in protected areas

Aim  One of the few general laws in ecology is that species richness is a positive function of area. However, it has been proposed that area would merely be a proxy for energy. Additionally, habitat heterogeneity has been found to be an important factor determining species richness. Yet the relative importance of those relationships is little known, and it is still unclear how they are brought about. We aimed to dissect which factors drive the species richness of boreal forest birds, and to identify the most probable mechanisms.
Location  Forested protected areas in Finland.
Methods  Using bird line census data collected in 104 protected areas, we ran simultaneous autoregressive models to explain the species richness of forest birds. We explored the value of forest area, tree volume, tree growth, mean degree days and habitat heterogeneity as explanatory variables and used the species richness within different species groups, based on the predictions of hypothesized mechanisms, as a response variable.
Results  Energy, rather than area or habitat heterogeneity, seems to be the main driver of species richness in boreal forest birds. More specifically, productive energy was a better predictor of total species richness than solar energy. Among the tested hypothetical mechanisms, the sampling hypothesis received strong support. After accounting for sampling, solar energy had an effect on species richness.
Main conclusions  As productive energy, such as tree volume, is associated with species richness, high-energy areas should be prioritized in forest conservation planning. Reductions in productive energy may first lead to the disappearance of the rarest species due to the random sampling process. Climate change may result in increased species richness due to increasing amount of productive and solar energy in forests. However, the range shifts of bird species may not be fast enough to keep up with the temperature increases.     

竞争和气候对新疆阿尔泰山西伯利亚五针松树木径向生长的影响

阿尔泰山的北方森林是中亚以及全球的生态系统的重要组成部分, 其生长动态可以影响到全球范围的热辐射、碳平衡等。因此, 探究影响阿尔泰山树木径向生长的主要因素至关重要。该研究以新疆喀纳斯国家级自然保护区的西伯利亚五针松(Pinus sibirica)为研究对象, 建立西伯利亚五针松年表, 通过分析不同时间间隔累年生长量、竞争指数以及气候因子之间的关系, 运用线性混合效应模型、相关分析等方法, 探究竞争和气候对新疆阿尔泰山西伯利亚五针松树木径向生长的影响。结果表明: (1)线性混合效应模型结果显示竞争树胸径和与西伯利亚五针松过去30年的累年生长量之间的拟合效果最好; (2)标准年表与3月的平均气温、平均最高气温、平均最低气温之间有显著正相关关系; (3)累年生长量最高值出现在气温0-5 ℃, 竞争指数低于100的时候。累年生长量最低时, 气温达到-10 ℃, 竞争指数也超过了300。目标树的树木径向生长受到竞争树胸径和及生长季前期气温的影响, 两者共同作用。但相较于气候因子而言, 竞争对西伯利亚五针松的树木径向生长有更大的影响作用。     

Effects of competition and climate on tree radial growth of Pinus sibirica in Altai Mountains,Xinjiang, China

阿尔泰山的北方森林是中亚以及全球的生态系统的重要组成部分, 其生长动态可以影响到全球范围的热辐射、碳平衡等。因此, 探究影响阿尔泰山树木径向生长的主要因素至关重要。该研究以新疆喀纳斯国家级自然保护区的西伯利亚五针松(Pinus sibirica)为研究对象, 建立西伯利亚五针松年表, 通过分析不同时间间隔累年生长量、竞争指数以及气候因子之间的关系, 运用线性混合效应模型、相关分析等方法, 探究竞争和气候对新疆阿尔泰山西伯利亚五针松树木径向生长的影响。结果表明: (1)线性混合效应模型结果显示竞争树胸径和与西伯利亚五针松过去30年的累年生长量之间的拟合效果最好; (2)标准年表与3月的平均气温、平均最高气温、平均最低气温之间有显著正相关关系; (3)累年生长量最高值出现在气温0-5 ℃, 竞争指数低于100的时候。累年生长量最低时, 气温达到-10 ℃, 竞争指数也超过了300。目标树的树木径向生长受到竞争树胸径和及生长季前期气温的影响, 两者共同作用。但相较于气候因子而言, 竞争对西伯利亚五针松的树木径向生长有更大的影响作用。     

Maintaining and restoring biodiversity in European boreal forests by developing natural disturbance regimes

Abstract. A conceptual model is presented as a guide to the maintenance and restoration of ecologically sustainable boreal forest. The model is based on the hypothesis that self-sustained forest ecosystems can be (re-)created, and their biodiversity developed, if forest management can simulate the composition and structure of boreal forest landscapes by introducing and maintaining disturbances leading to naturally dynamic spatial and temporal patterns of forest regeneration. The major explanatory variable in the model is the effect of wildfire on sites with different fuel characteristics and climates found in the European boreal forest. Four levels of fire intensity are distinguished, based on mean fire frequencies. These range from extremely low in some wet tall-herb sites or sites at high altitudes or latitudes with a humid climate, where fire is absent or rare, to dry lichen-rich sites where fire occurs often. The model is called ASIO, after the words Absent, Seldom, Infrequent and Often, indicating the four levels. Three main disturbance regimes are distinguished in the European boreal forest, based on the complex interactions between probabilistic (e.g. mean fire intervals at different site types) and random events (e.g. where and when a fire occurs): (1) gap-phase Picea abies dynamics; (2) succession from young to old-growth mixed deciduous/coniferous forest; and (3) multi-cohort Pinus sylvestris dynamics. The model stems mainly from studies in Fennoscandia, but some studies from outside this region are reviewed to provide support for a more general application of the model. The model has been implemented in planning systems on the landscape level of several large Swedish forest enterprises, and is also used as an educational tool to help private land owners with the location and realization of forest management regimes. Finally, the model can be used to develop an administrative system for the monitoring of biodiversity in boreal forest.