武夷山国家级自然保护区黄山松天然林自然稀疏规律研究

选择平均直径、平均木断面积和林分总断面积作为林木个体大小的指标,研究林木株数与林木大小的关系.应用-3/2法则,建立黄山松天然林自然稀疏过程中林分密度与平均直径、平均木断面积、总断面积的相关关系.结果表明:黄山松天然林种群密度对林分平均胸径、平均木断面积、林分总断面积均存在显著作用.因此,在经营黄山松天然林时,必须切实重视林分密度控制管理.     

樟子松人工林树冠表面积及体积预估模型的研究

基于樟子松(Pinus sylvestris var. mongolica)人工林6块固定标准地30株枝解析数据,在分析树冠表面积和树冠体积与林分变量和林木变量的基础上,利用幂函数建立了树冠表面积（CSA）和树冠体积(CV)的预估模型,同时还对林木材积生长量与CSA和CV进行了相关分析。研究结果表明：樟子松人工林树冠表面积和树冠体积随着林木胸径、树高和冠长的增大而增大,林木材积生长量与树冠表面积和树冠体积均明显呈线性关系。不同林分条件的樟子松人工林CSA和CV随林分年龄和胸径的增大而增大,CSA随林分密度的增大而减小,而CV与林分密度相关不紧密。林分树冠表面积和树冠体积预估模型的检验结果表明,两个模型的平均相对误差都在±8%之内,预估精度均大于91%,说明所建模型可以很好地预估樟子松人工林不同林分条件下的林木树冠表面积和树冠体积。     

樟子松人工固沙林稳定性的研究

提出了人工林稳定性的内涵及其评价标准．分析了影响沙地樟子松人工林稳定性的各种干扰因子,通过对沙地樟子松人工林造林成活、生长情况、对不良外界环境的抗御能力、林分寿命、林分结构和生产力的综合评价分析,认为沙地樟子松引种人工林基本上是稳定的;而生长在立地较好的丘间低地的林分,其稳定性大于沙丘顶部的林分;从抗枯梢病角度看,幼林的抗性大于中林;从林分密度和生产力角度来看．红花尔基沙地樟子松林稳定性高于章古台．     

降水量下限引种区沙地樟子松幼林种群树高分布偏斜度和不整齐性

对降水量下限引种区沙地樟子松自然稀疏前人工林种群树高分布偏斜度和不整齐性的研究表明,种群高生长的不整齐性和分布的不对称性在林分自疏前随着林分发育而下降,造成高生长事整齐性变化的因素主要有年龄,初始生长状况,种群密度,对土壤水分的竞争和沙丘部位的差异;沙丘部位对林分不整齐性的影响作用要大于密度。     

樟子松沙地人工林直径分布模拟

利用反 Weibull函数模拟了章古台沙地樟子松人工林的直径分布规律 .结果表明 ,反 Weibull分布函数模拟樟子松人工林的直径分布效果好 ,具有精度高、适应性强等特点 .分别建立了反 Weibull分布函数 3个参数与林分年龄及密度之间的关系方程以及直径分布与 3个参数的回归方程 ,这些方程可用来预估林分产量、出材量以及评价经营效果     

樟子松固沙林林水关系研究进展及对营林实践的指导

中国有着世界上最大面积的人工林, 如何维持人工林的可持续性已成为气候变化背景下需要面对的重大挑战。樟子松(Pinus sylvestris var. mongolica)以其抗旱、抗寒、耐贫瘠等优良特性成为中国北方生态治理中最主要的常绿针叶树种之一, 近70年来发挥了巨大的防风固沙与生态固碳功能。然而, 随着林分的生长与气候变化, 樟子松人工固沙林正经历着越来越严峻的环境胁迫, 部分地区出现了林分“早衰”或死亡的现象, 引起了人们对樟子松固沙林适应与应对气候变化能力的担忧。该文在回溯樟子松基本生物学特征与引种推广历史, 系统总结近年来樟子松林林水关系研究新成果的基础上, 全面分析了樟子松固沙林林水关系存在的主要矛盾, 并提出了基于林水关系相协调的林分经营措施的调整: 由倡导防护功能为主的单一目标向包含林分稳定性、生态固碳功能、可持续发展等多目标平衡方向调整; 由以沙地森林景观培育为主向以良好土壤生境培育为主的方向调整; 由倡导天然更新为主向以人工造林与天然更新相结合的世代更新方向调整。在立足于北方沙地脆弱生境与气候变化客观现实的基础背景下, 应坚持樟子松在固沙林生态系统演化过程中的先锋种与建群种地位, 基于“以水定绿”原则, 采取“隔行带伐+再造林”等方式开展林分密度动态调控, 促进林分向异龄林结构演化, 促进樟子松固沙林生态服务的优质化和生态固碳功能的最大化。     

基于沙地樟子松人工林衰退机制的营林方案

沙地樟子松是三北防护林工程中最重要的常绿针叶造林树种。然而,自20世纪90年代初起,最早引种的沙地樟子松人工林在林龄30~35 a后出现枝梢枯黄、长势衰弱、病虫害发生、继而全株死亡且不能天然更新的衰退现象。以科尔沁沙地的樟子松疏林草地和呼伦贝尔沙地的樟子松天然林为参照,以热扩散、稳定同位素和遥感监测等技术开展的系列研究,基本明确了樟子松人工林衰退机制。本文对以往相关研究结果进行了系统总结:确定了沙地樟子松人工林严重水分胁迫的土壤含水量阈值(20%田间持水量),阐明了沙地樟子松人工林水分利用策略(9~21年生樟子松人工林仅利用土壤水,而31~41年生既利用土壤水也利用地下水),明确了沙地樟子松人工林水量平衡特征(水量失衡,吸收至少39mm地下水方能维持水量平衡),量化了樟子松人工林耗水对区域水资源消耗的贡献(消耗12.3%水资源),揭示了樟子松人工林衰退过程,找出了樟子松人工林发展存在的问题及产生的原因。在此基础上,提出了解决衰退对策与营林方案,为防止现存沙地樟子松人工林衰退、合理经营,未来该林种合理布局提供参考。     

沙地樟子松人工林营林技术研究进展

人工林能否实现可持续经营与其营林技术息息相关。中国造林与世界各地一样,纯林多．树种单调．发生的问题也相似。自20世纪90年代以来,沙地樟子松人工林出现了不同程度的衰退现象．但目前在我国北方干旱、半干旱风沙地区樟子松人工造林仍在大面积推广．因此,为实现樟子松人工林的可持续经营,总结并探讨樟子松人工林营林技术显得尤为重要。本文在广泛收集国内外有关樟子松研究的基础上,综述了近20年来有关樟子松在造林和经营方面的研究进展,主要包括造成樟子松沙地造林成活率和保存率低的原因、提高造林成活率的技术方法、种子的生产、密度管理、栽培模式以及问伐与更新等,提出了在沙地樟子松造林与经营研究中亟待解决的一些问题和建议．对今后樟子松沙地人工林衰退研究及经营实践具有参考价值。     

河北塞罕坝樟子松人工林生长及碳储量的变化

樟子松(Pinus sylvestris var.mongolica)作为华北地区重要的造林树种,其生长及固碳特征的研究对樟子松人工林经营有着重要的意义。该文通过2006–2016年10年的定点观测,研究河北省塞罕坝林场樟子松人工林的生长和固碳特征。结果表明:10年间樟子松人工林胸径年增长4.19%,树高年增长1.97%;林木死亡率8.39%。该林分2006年和2016年的碳储量分别为59.04和109.64 t×hm~(–2),即10年间固碳量为50.6 t×hm~(–2),固碳年平均增长8.57%。不同径级的林木固碳能力有差异,0–10 cm径级的林木总株数占39.1%,但固碳量仅占8.3%;10–20 cm径级的林木株数占59.2%,固碳量占比达87.1%。结果显示樟子松人工林具有较大的固碳潜力,未来评估林分生态效益与固碳潜力时,应充分考虑林分的结构特征。     

杉木人工林林分叶面积动态变化规律

叶面积与树木生长密切相关,是量化树木潜在生产能力的重要因子,其动态变化直接驱动林木生长的变化,但目前学者们对于林分叶面积动态变化规律却持有不同的观点。以亚热带不同气候区杉木人工林为研究对象,基于54个样地,共144株解析木的数据,采用6种生长方程通过非线性混合效应模型分别构建杉木单木叶面积模型和林分密度模型,将二者相乘得到林分叶面积动态变化模型,进而探究其动态变化规律。结果表明,以样地作为随机效应因子,考虑Logistic方程a参数上的随机效应,同时不考虑异方差结构的混合模型(样地水平)作为单木叶面积的最优模型;以地区作为随机效应因子,考虑Logistic方程a参数上的随机效应,同时不考虑异方差结构的混合模型(总体平均水平)作为林分密度的最优模型;林分叶面积动态变化呈单峰形式,幼龄阶段增长较快,达到峰值后迅速下降,之后下降幅度减少。本研究在考虑林分自然稀疏的前提下从生长模型的角度证明了杉木林分叶面积动态变化呈单峰型,而非达到顶峰后保持不变,同时也表明林分叶面积达到顶峰后下降是由于林分密度的降低引起的。研究结果对于合理经营不同气候梯度的杉木人工林具有重要意义。     

Impact of Habitat Fragmentation on the Demography of Lion-tailed Macaque (<Emphasis Type="Italic">Macaca silenus</Emphasis>) Populations in the Rainforests of Anamalai Hills,Western Ghats,India

Habitat fragmentation is considered the most serious threat to primate conservation in the tropics, and understanding it effects on lion-tailed macaque is very important because most of the populations live in fragmented habitats. We examined demographic parameters of 9 lion-tailed macaque groups in 8 rain forest fragments with reference to fragment area, tree density, canopy cover, tree height, and total basal area of food trees. Group size ranged from 7 to 90 individuals but was not related to habitat variables. Birth and growth rates of groups did not differ significantly between small (n = 4) and large (n = 4) fragments. Tree density, canopy cover, and total basal of food trees all show strong positive correlations with fragment area. Growth rate correlates with tree density, but there are no other significant relationships between birth or growth rate and habitat variables. The percentage of immature individuals in the group is significantly positively associated with the total basal area of food trees, but not with any other habitat variable. Comparison of our data from this study with data available for the same population in 1996 indicates a slight decline in birth rate but an increase in total number of individuals, from 154 to 242. Of the 5 small fragment groups, 3 have increased in size since 1996 while the sizes of the other 2 groups have remained the same. Based on this study, we advocate that to manage the fragile lion-tailed macaque groups the following steps need to be taken: 1) create dispersal corridors between the fragments using fruit trees to facilitate male dispersal, 2) construct canopy bridges across the prevailing roads, 3) protect the fragments from further degradation, and 4) periodically monitor these populations for long-term conservation.     

长白山次生杨桦林树木短期死亡动态

以长白山次生杨桦林5 hm²样地为对象,以2005和2010年两次调查数据为基础资料,分析了2005-2010年间样地主要树种的组成、数量,死亡个体的径级分布,以及不同生境类型下主要树种的更新特征.结果表明： 研究期间,样地内树木胸径(DBH)≥1 cm的独立个体的树种数由46种增至47种,新增3个树种,2个树种因仅有的一个个体死亡而消失;独立个体数由16509株减少为15027株,其中,死亡个体数2150株,占2005年个体总数的13%,新增个体数668株,净减少1482个个体;样地树木的胸高断面积由28.79 m²·m^-2增至30.55 m²·m^-2,有41个树种的胸高断面积增加,6个树种减少,其中,山杨和白桦的减少量占总减少量的72.3%;小径级个体的死亡量较大,DBH＜5 cm个体的死亡量占总死亡量的65%,山杨和白桦是大径级个体死亡的主要树种.不同生境类型下个体死亡率差别不大,但各径级间的树木死亡率则有较大差异.     

Root architecture,early development and basal sweep in containerized and bare-rooted Douglas fir (Pseudotsuga menziesii)

Seedlings grown in containers often have deformed, spiralling, kinking root systems (reported especially in pine growing in colder climates like Fenno-Scandinavia). The current study examines the effect of containers on the root systems of Douglas fir planted in Ireland. A sample of sixteen 10-year-old Douglas fir trees, planted as either bare-rooted transplants (2/1) or containerized seedlings (Paperpot 610 (2/0)) on an acid brown earth site in Ireland, were excavated for root achitectural studies. In addition to thorough above-ground measurements, an assessment of basal sweep was also carried out. Root systems were systematically described and horizontal angles, cross-sectional areas (CSA), and maximum depths of all roots>5 mm in diameter were recorded. Various biomass ratios and estimates for dominant roots were also calculated. Symmetry of the root systems, max. and min. numbers, and CSA of roots for sectors of various sizes were compared for the two plant types. The initially (when planted) bigger bare-rooted transplants were still larger than the container-planted trees after ten years. Of the total above-ground fresh weight, the container stock had allocated more to the crown and less to the stem compared to bare-roots. The difference in root weights between stock types was small. Basal sweep occurred on average in 50% of the bare-roots and 35% of the container trees. The direction of the basal sweep leaning was concentrated to the NE, which coincided with the direction of the slope and the prevailing wind direction. No effect of planting position in relation to the direction of site preparation was found for basal sweep. The size of the root system, fresh weight and total cross-sectional area was on average for all trees correlated to both DBH and shoot fresh weights. For containers separately, however, only root area was correlated to DBH and stem fresh weight. In spite of the difference in the above-ground size, there were no significant differences in root numbers and root area (CSA) between the two plant types. No difference in rooting depth between plant types was found. When splitting the root system into 120° horizontal sectors (1/3 of the root system) the highest numbers of roots were concentrated in the NW direction. The highest amount of root area tended to be concentrated along a NW-SE diagonal, with a dominance for the latter (SE). Sectors without dominant roots (expected to be the future main structural, stabilizing roots), varied in size (94–178°) but were on average wider in bare-roots and on average concentrated in the NE direction and the downhill side of the slope. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同坡向川西亚高山林木竞争与叶片表型可塑性的关系研究

表型可塑性是植物生长响应外界环境变化的重要表现形式,体现了植物个体在环境胁迫下的适合度。但是关于植物表型可塑性的驱动机制仍然存在很多争议。为了探讨植物表型可塑性的影响因素,以四川省阿坝藏族羌族自治州位于同一海拔梯度但坡向相反的天然次生林为研究对象,分析了不同坡向竞争强度与10种树木叶片功能性状表型可塑性的关系的差异。研究发现：(1)研究样地中阴坡水分和养分资源优于阳坡;(2)阴坡上林木平均种内和种间竞争强度高于阳坡,阴坡上林木种内竞争强度随着树木个体大小的增加而显著性减少,阳坡上林木种内竞争强度却随着个体大小的增加而增加;(3)阴坡上叶片表型可塑性高于阳坡,表型可塑性随着个体大小的增加而增加,在阳坡上却随着个体大小增加而降低。这些结果表明阴坡上水分等资源环境条件优于阳坡,林木生长受到环境资源限制较少。在林木生长过程中,较高的竞争强度引起的资源重叠加剧,尤其是种内竞争强度的变化,从而导致了阴坡上较高的叶片表型可塑性。因为较高的竞争强度,随着林木个体大小的增加,树木需要更高的可塑性赢得竞争优势来获取更多的资源支持生长。但是在阳坡上,资源相对缺乏,环境资源对树木生长的限制降低了叶片表型的可塑...     

The role of remnant trees in carbon sequestration,vegetation structure and tree diversity of early succession regrowing fallows in eastern Sierra Leone

Remnant tree presence affects forest recovery after slash‐and‐burn agriculture. However, little is known about its effect on above‐ground carbon stocks, especially in Africa. We focused our study on Sierra Leone, part of the Upper Guinean forests, an important centre of endemism threatened by encroachment and forest degradation. We studied 99 (20‐m‐radius) plots aged 2–10 years with and without remnant trees and compared their above‐ground carbon stocks, vegetation structure (stem density, basal area) and tree diversity. Above‐ground carbon stocks, stem density, basal area, species richness and tree diversity increased significantly with fallow age. Remnant tree presence affected significantly tree diversity, species dominance and above‐ground carbon stocks, but not vegetation structure (stem density, basal area). Number of remnant trees and number of species of remnant trees were also important explanatory variables. Although other factors should be considered in future studies, such as the size and dispersal modes of remnant trees, our results highlight that more strategic inclusion of remnant trees is likely to favour carbon stock and forest recovery in old fallows. To our knowledge, this is the first study on early succession regrowing fallows in West Africa.     

Vessel-element dimensions and frequency within the most current growth increment along the length of Eucalyptus globulus stems

The mean number of vessels per unit area in the outer most growth increment at six percentage heights in individual trees, viewed in transverse section, showed an increasing trend from basal to apical regions. The highest frequency of vessels occurred at 90% of total tree height (23.58 mm^-2) while the lowest frequency (9.99 mm^-2) was recorded at 15% of total tree height from the base. Vessel elements were largest at 15% of total tree height and proceeded to decrease in size with increased stem height. Average radial measurements ranged between 111.27 µm and 160.0 µm while average tangential measurements ranged between 76.30 µm and 112.80 µm. There was variation seen at each percentage height between collection dates (i.e. individual trees); however, the trend of increasing vessel frequency from basal to apical regions existed regardless of between-tree variation in dimensions. Vessel-element dimensions showed a similar, but inverse trend to vessel-element frequency with the largest vessel elements located at 15% of total tree height and the smallest vessel elements located at 90% of total tree height.     

长白山阔叶红松林树木种群动态的长期监测

基于1981-2016年对长白山阔叶红松林固定样地(面积 1 hm²)4次调查的监测数据,研究了阔叶红松林树种组成与结构的变化特征,分析了各树种的径阶分布、空间分布、数量变化等.结果表明: 35年间,林分的树种组成变化不大,林分总密度呈下降趋势.总胸高断面积和蓄积量分别为 43～45 m²·hm^-2和474～496 m³·hm^-2,其中,红松的优势度最大,胸高断面积和蓄积量分别占57.8%～59.7%和62.5%～65.4%.所有优势树种的空间分布无明显变化,均呈随机分布.其中,红松的径级结构呈近似正态分布,乔木层全部树种的径级结构呈倒 “J” 型分布.小径级(10～26 cm)死亡个体的绝对数量最多,死亡比例为30%,而中径级(30～50 cm)死亡比例最高,为30%～50%.乔木层中除色木槭外的主要树种均没有明显进阶,死亡率高于更新率,特别是红松,完全没有更新或进阶,种群处于衰退状态.原始阔叶红松林中红松、紫椴等优势树种的更新受到阻碍,这些树种的种群维持可能需要自然干扰.     

The relationship between fruit production and primate abundance in Neotropical communities

Ecological models predict a positive correlation between fruit production and primate abundance in the Neotropics. To test this relationship, I compiled information on primate abundance and calculated different indexes of fruit production for 30 Neotropical sites. These indexes can be grouped in three categories: (1) Fruit production estimates based on fruit traps, (2) basal area of endozoochorous trees and (3) density of these trees. The first estimate was the best predictor of both primate biomass ( r ²= 0.80) and species richness ( r ²= 0.64). The advantage of using fruit trap estimates is that they take into account production rates (which is not the case for basal area or density estimates), while the advantage of using basal area over density estimates is that it includes some of the expected variation due to tree size. However, using both basal area and density indexes I found a positive correlation between the basal area index and primate biomass for frugivorous monkeys and small platyrhines, but there was no correlation for folivorous and seed predator primates. I also found a positive correlation between pitheciine biomass and the abundance of Eschweilera trees. The analyses gave little support to the importance of suggested keystone resources such as figs and palms. Finally, when including climatic, geographic and plant diversity variables, fruit production continued to be a good predictor of primate biomass in the Neotropics, but primate species richness was best predicted by latitudinal gradients and plant species richness.     

天童山森林土壤种子库的时空格局

土壤种子库是植物群落的潜在物种库。在中国东部典型丘陵地区天童国家森林公园内选取8类微地形, 分别于2008年9月、12月和2009年3月、6月进行野外调查取样和室内实验, 从总计1,960份土样中挑选种子进行鉴定及分类统计, 研究其时空格局, 探讨自然森林土壤种子库的基本特征及分布规律。结果显示: (1)共检出有活力的种子5,024粒, 共鉴定出68个种, 其中定名种65个; 落叶阔叶乔木和常绿阔叶小乔木物种数量以及种子数量均占优势; 土壤种子库与地上植被共有种为48种, 相似性系数为0.45。(2) 2级和3级顶坡及下部边坡、麓坡、泛滥性阶地种子库储量较大, 而高上部边坡、中上部边坡和低上部边坡种子库储量较小。雷公鹅耳枥(Carpinus viminea)和细枝柃(Eurya loquaiana)是各个微地形单元种子库的优势种。其他优势种中, 上部坡面的微地形主要为格药柃(E. muricata)、短梗冬青(Ilex buergeri)、黑山山矾(Symplocos heishanensis)、四川山矾(S. setchuensis)等常绿树种, 而下部坡面的微地形主要为南酸枣(Choerospondias axillaris)、橄榄槭(Acer olivaceum)、西川朴(Celtis vandervoetiana)等落叶树种。(3)土壤种子库储量在垂直空间上的分布是0-2 cm土层>2-5 cm土层>5-10 cm土层>枯枝落叶层。(4)土壤种子库具有明显的季节动态, 其储量在各个取样时间中的分布为12月>3月>9月>6月。