为定量评价木林子天然林不同恢复阶段林分结构特征变化及森林恢复现状,以木林子自然保护区内皆伐后自然恢复24、39 a的次生林及未受人为干扰的原始林为研究对象,通过林分空间结构参数分布、径阶-空间结构参数联合分布来量化描述林分径阶和空间结构特征,并采用林分空间结构指数(I)和林分空间结构距离(D)综合评价不同恢复阶段林分整体结构特征.结果表明:木林子天然林不同恢复阶段林分均混交良好,随恢复时间的推移,该林分水平分布格局整体趋势由聚集分布向随机分布发展,大小分化度呈先增加后降低的趋势,但始终趋于均衡状态.空间结构参数方差检验表明,在自然恢复过程中,大小比数、混交度能更快地趋于合理,而角尺度则需要较长时间的恢复.径阶-空间结构特征表明,各个恢复阶段林木均以随机林体为主,其中原始林林分中随机分布格局下极强度混交状态的林木胸径更大.不同恢复阶段,绝对优势等级林木中原始林的径阶区间最广.相较于24年生及39年生次生林林分,原始林空间结构最优,林分空间结构指数、林分空间结构距离分别为0.724、0.544.皆伐后自然恢复24、39 a的次生林需较长时间才能达到原始林的结构状态.

【Objective】The objective of this study was to compile and analyze the biomass models of woody plants in subtropical evergreen and deciduous broad-leaved mixed forests, learn the status of biomass models in the plant list based on sample-plot surveys, and provide references for researchers to calculate and evaluate biomass, thus providing a research direction for improving the biomass models of woody plants in such forests and references for formulating the unified standard of biomass modeling.【Method】Based on the survey of the fixed monitoring plots in the evergreen and deciduous broad-leaved mixed forests of 3 nature reserves and 1 state-owned forest farm in southwest Hubei province, the species list was determined, the woody plant biomass models were retrieved, screened and organized, and the model structure, parameters and factors that affect the accuracy of the model were analyzed.【Result】A total of 665 biomass models were obtained from 167 groups, including 55 families, 110 genera and 270 species of plants, which covered 60% of the 455 plant species in the species list. The model set contained 19 independent variables, which were mainly diameter at breast height D, base diameter DB, tree height H, etc., as well as their different combinations like D2H and DB2H, and 5 types of functions which included 388 power functions, 121 linear functions, 73 polynomial functions, 68 logarithmic functions, and 15 exponential functions. In the model set, 568 models (85.4%) marked the range of independent variables, 596 models (89.6%) marked the standard number of trees for modeling, and the biomass models with over 30 samples accounted for a low proportion (22.3%). 559 models (84.1%) marked the correlation coefficient or coefficients of determination (such coefficients range from 0.17 to 0.99, with an average of 0.91) to reflect the accuracy of the model. The independent variables of models, sample size, function type and different organ components and life forms of trees would all affect the accuracy of the model.【Conclusions】There is still a lack of biomass models of woody plants in subtropical evergreen and deciduous broad-leaved mixed forests, and the existing models have problems such as insufficient sample size and incomplete statistical parameters. The accuracy of the model is affected by sample size, independent variables, function type and other factors.

To explore the population quantitative characteristics and regional distribution of wild Viburnum plants in Southwest Hubei, and reveal the survival status and development trend of the following five Viburnum species: V. erosum, V. betulifolium, V. sympodiale, V. setigerum and V. dilatatum. A total of 27 hm2 dynamic monitoring stands were set up in Jinzi Mountains National Forest Farm, Mulinzi National Nature Reserve and Qizimei Mountains National Nature Reserve in Southwest Hubei. The age structure, dynamic quantitative analysis and static life table of five Viburnum species were used to explore the population structure, dynamic characteristics and future development potential of Viburnum plants. The results were as follows: (1) The distribution area and population size of Viburnum plants in Southwest Hubei were significantly different. (2) The age structure of the five Viburnum species displayed as the pyramidal type summarized from population structure and dynamic analysis. The number of individuals of each population was large at the young stage (89.48% of V. erosum in Jinzi Mountains, 76.38% of V. betulifolium, 67.24% of V. erosum in Mulinzi, 62.11% of V. dilatatum, 56.53% of V. sympodiale, 58.44% of V. setigerum), and only a small proportion of individuals (0.18% of V. erosum in Jinzi Mountains, 0.85% of V. betulifolium, 3.29% of V. erosum in Mulinzi, 3.97% of V. dilatatum, 8.37% of V. sympodiale, 2.79% of V. setigerum) at the old stage. The young stage plants of five Viburnum species all had strong growth potentials but were sensitive to external disturbances. (3) The survival quantity of the five Viburnum species was decreasing monotonically with increasing age class presented by static life tables. Except for V. setigerum, the life expectancy reached peak at the young age, all the other Viburnum species populations reached the peak at the middle age. The change trend of mortality rate and vanish rate were similar, but the fluctuation of vanish rate and mortality rate curves were different among different species. The survival curves were tended to be Deevey-Ⅱ type. (4) The four survival function curves showed that all five Viburnum species populations exhibited a substantial decrease at the early stage, stabilization at the middle stage, and decline at the late stage. To sum up, plant resources of Viburnum species are abundant in Southwest Hubei. Therefore, it is scientific and feasible to exploit Viburnum plants rationally. At the young stage, artificial thinning can be carried out appropriately to improve the preserving rate. During the stable middle stage, the dominant species which have good ornamental characters can be selected for appropriate development and utilization. However, some species need to be protected to maintain biodiversity in this area.

It provides a theoretical basis for the artificial promotion of the reproduction and regeneration of Liriodendron chinense through exploring the effects of light intensity and seeding density on the seed germination and seedling growth of this rare plant. Controlled experiments were conducted by setting different seeding densities and shading intensities to observe and detect the seed germination and seedling growth under different experimental conditions. The data were analyzed by SPSS and the model was fitted to calculate the seed germination rate, seedling emergence rate and seedling growth parameters of Liriodendron chinense, which were used to analyze the effects of seeding density and light intensity on the seed germination and seedling growth of Liriodendron chinense. Light has a significant impact on the seed germination and seedling growth of Liriodendron chinense (P P > 0.05). High density promotes the seedling height (the seedling height showed a rising trend with the increase of seeding density, reaching the highest at 500 seeds/m2. “3-stitch + 300 seeds/m2” combination is an appropriate condition for Liriodendron chinense reproduction since it can realize higher germination rate and better seedling growth potential. The seedling height and basal diameter growth curve of Liriodendron chinense fits well to the Logistic equation (R2 ≥ 0.977). Light has a significant impact on the seed germination and seedling growth of Liriodendron chinense, and appropriate shading treatment can increase the seed germination rate and seedling emergence rate of Liriodendron chinense. Seeding density has little influence on the seed germination rate of Liriodendron chinense, but high density will promote seedling height.

[目的]探究林分空间结构、物种多样性随尺度变化的规律及林分空间结构与物种多样性的相互关系,为鄂西南常绿落叶阔叶混交林可持续经营提供科学依据.[方法]以鄂西南七姊妹山自然保护区、木林子自然保护区和金子山国有林场3个研究区的典型植被——亚热带常绿落叶阔叶混交林为研究对象,基于各研究区大样地调查数据,分析从20 m×20 m到200 m×200 m不同尺度下,林分空间结构指标和物种多样性指数及其随尺度变化的规律,结合Pearson相关系数法解析尺度变化影响下的空间结构指标与物种多样性的相关性.[结果]鄂西南地区常绿落叶阔叶混交林中物种丰富,常见优势乔木树种为川陕鹅耳枥、多脉青冈和锥栗.林分空间结构特征在尺度 ≥120 m×120 m后变化趋于稳定,整体表现出微聚集分布、大小分化中庸且混交良好的状态.不同尺度上林分空间结构参数角尺度与林分物种多样性存在中度相关性(P<0.01),其他结构参数与林分多样性不存在相关性.[结论]鄂西南亚热带常绿落叶阔叶混交天然林,林分空间结构调查的最适尺度为120 m×120 m;不同研究尺度下,角尺度是林分空间结构影响物种多样性的一个关键因子.

Bretschneidera sinensis is positioned at the national secondary level of protection plant.This research is to analyze dynamic quantitative in species based on natural B.sinensis,project a static biotic clock, map out surviving curve for the species, analyze its living conditions, prob into species formation and dynamic characteristics in natural species by ways of investigation and statistics of B.sinensis based on the aged levels for the entirely individuals for the goals of looking into the species resource amount at Mulinzi National Natural Reserve.The results shows that species growth is limited by the instruction of environment from human and limitation of growth conditions in the early phase of plants.Thus, Appropriated measures, such as disturbance from human, should be taken to improve its livability of saplings to protect the living environment and mother plants, which is essential to improve its natural update in B.sinensis.

Tree biomass equations are the most commonly used method to estimate tree and forest biomass on various spatial and temporal scales because of their minor damage, ease of use, and high relative accuracy. The systematic compilation of models for the biomass of mixed evergreen and deciduous broad-leaved forest (a unique and essential class of typical vegetation types in the subtropical zone of China) has not been reported so far. In this paper, we compiled a species list through an inventory of 28.9 hm2 of mixed evergreen deciduous broad-leaved forests in southwestern Hubei Province with fixed detection sample plots, produced a species list, and used it to retrieve, collect and establish a model dataset of woody plant biomass in subtropical mixed evergreen and deciduous broad-leaved forests. The species list contains a total of 665 biomass models in 167 groups as well as the information corresponding to each mode, such as the plant species name, Latin name, plant life type, plant components calculated by the model, model independent variables, measurement units and ranges of independent variables, model correlation coefficient or coefficient of determination, model sample size, climate zone, and soil type. is also recorded. By establishing this dataset, this paper not only provides essential information for in-depth research on the productivity and carbon sink of this specific vegetation but also serve as a scientific basis for the management of this type of forest, the conservation of biodiversity, and the evaluation of forest ecological benefits.

该研究以鄂西南木林子国家级自然保护区内天然林为研究对象,以森林内胸径≥5 cm的乔木个体为具体分析对象,通过乔木树种重要值及其角尺度、大小比、混交度等林分空间结构参数的一元分布,阐述林分空间分布格局、大小分化程度、林木混交程度及变化,并通过分析林分空间结构参数的二元分布,探究各参数之间的联系,揭示5年间其林分空间结构特征及动态变化,为该林分类型的森林可持续经营提供准确的数据,以促进林分结构理想化,维持该区域物种多样性.结果 显示:(1)2014年与2019年林分中主要建群种均为青冈(Cyclobalanopsis glauca),该种在群落中处于优势地位,鹅耳枥(Carpinus turczaninowii)重要值提高0.63％,其在林分中的相对重要性超过杉木(Cunninghamia lanceolata)位居第二,说明在该群落中鹅耳枥具有稳定的种群结构.(2)林分整体依然处于轻微团状分布状态,且各树种强度混交,平均混交度增长0.02,大小比均值降低0.01,林分生长依然处于中庸状态,5年来林分整体空间结构变化较小,但处于由当前林分结构向理想结构的过渡阶段.(3)结构参数两两组合的各组林分空间结构二元分布中,各参数不同取值等级的变化趋势基本不变,但大小比和混交度的二元分布结果显示林分中处于绝对劣势、劣势且零度混交、弱度混交的林木个体减少,林分稳定性得到提高.研究表明,研究区内天然林分空间结构动态变化虽不明显,但处于向更好、更稳定的结构发展中.

[目的]为进一步探究鹅掌楸种群的天然更新、稳定与演替机制,合理保护现有资源,对湖北鹤峰鹅掌楸天然种群进行调查.[方法]通过建立静态生命表,绘制存活曲线描绘种群结构特征,利用种群数量动态量化分析方法和时间序列预测研究其未来的发展趋势,结合扩散系数判断物种在不同龄级的集聚与分散状态,分析鹅掌楸天然种群的年龄结构与数量动态及分布格局.[结果]1)种群Ⅰ～Ⅵ中小龄级个体占比88.4％,Ⅴ～Ⅶ大龄个体占比33.61％,Ⅶ～Ⅹ老龄个体占比11.62％,总体呈不规则的金字塔型,高度在第Ⅴ级(20～25 m)个体数量最多,总体呈单峰型;2)种群死亡率单调上升,在第Ⅷ龄级达最大值(qx=75％),期望值在第Ⅰ龄级最高(ex=4.43),随后逐渐降低,存活曲线趋向于Deevey-Ⅱ型,动态指数显示种群为增长型,对外界干扰具有一定敏感性.整个种群呈现前期缺乏、中期稳定、后期衰退的动态特征,种子发芽率低、幼苗成活率差是导致其衰退的重要原因之一;3)种群在不同径级均为集聚分布,聚集度随着龄级的增长逐渐下降.[结论]鹅掌楸天然种群中中小龄级个体数量相对较多,未来一段时间内将发展良好,但幼龄与老龄个体严重缺乏,因此,提高种子萌发率与幼苗存活率是促进种群恢复更新的关键.

[目的]以湖北省恩施土家族苗族自治州鹤峰县鹅掌楸(Liriodendron chinense)天然林为研究对象,通过分析其物种组成与林分空间结构,直观、精准的描述其林分结构特征,为我国珍稀植物鹅掌楸的可持续经营提供理论依据.[方法]在两个鹅掌楸典型分布区域共建立40个20m×20m调查样地,进行每木定位与检尺调查,利用Winkelmass软件与R 3.5.1计算胸径(DBH)≥5cm的林木个体的角尺度(W)、大小比(U)、混交度(M)与密集度(C),分析其一元分布、二元分布及四元分布特征.[结果]群落中物种总计251种,其中乔木88种、灌木61种、草本77种、木质藤本25种,隶属于76科172属,鹅掌楸为该群落的优势种群,但优势不明显.鹅掌楸天然林林分角尺度均值为0.566,整体呈现轻微团状分布,林木生长处于中庸状态(U=0.508),各树种呈现高度混交状态(M=0.742),林分郁闭度较高,密集度均值为0.865.角尺度对大小比数、混交度与密集度均有一定影响,且林木混交状态与林分密集程度呈现相互促进的状态.[结论]研究区鹅掌楸天然林各树种高度混交,正处于森林自然演替的中后期阶段.森林经营过程中应调整林木个体之间的竞争关系,减少同种聚集现象,选择性地伐除处于绝对劣势且弱度混交的林木个体,改善林内环境,增加林下光照,促进鹅掌楸天然更新,以维持森林结构的稳定与可持续发展.

为了明确鄂西南木林子亚热带山地常绿落叶阔叶混交林的短期群落动态,为该区森林生态的保护、恢复与可持续经营提供科学依据.该研究基于木林子自然保护区2.2 hm2动态监测样地,以2014和2019年样地内所有胸径(DBH)≥1 cm的木本植物为研究对象,从物种组成与多样性、重要值、死亡率、补员率及胸径等方面分析了其动态变化.结果表明:(1)5年间2.2 hm2样地内木本植物个体从17308株减少到16533株,降幅为4.48％,胸高断面积31.42 m2·hm-2增长到35.53 m2·hm-2,物种增加了1科6属18种,消失1属7种.乔木、亚乔木、灌木及藤本4类生长型物种的Margalef丰富度指数均上升,而Pielou均匀度指数均下降;除乔木外其他3种生长型的Shannon-Wiener多样性指数和Simpson指数均上升.(2)补员个体1269株,平均胸径2.44 cm,胸高断面积为0.32 m2·hm-2,平均新增115.36株·hm-2·a-1,隶属39科59属99种;死亡个体2044株,平均胸径3.32 cm,胸高段面积为1.31 m2·hm-2,平均死亡185.82株·hm-2·a-1,隶属51科90属146种;不同径级补员与死亡个体数差异明显,总体上随着径级的增大而减少.(3)46个主要物种中有15种重要值增大,有31种降低,增加与降低的变化幅度为乔木层>灌木层>亚乔木层;平均胸径从4.70 cm上升为5.12 cm,除锥栗(Castanea henryi)平均胸径有所下降外其他物种均上升.(4)主要树种中有44个为增长型种群,另外2个物种种群增长率不变,主要物种年补员率大于年死亡率,不同生长型物种及其不同径级的死亡率与补员率不同,不同径级补员率总体大于死亡率;随着径级的增大,补员率与死亡率的差值逐渐降低趋于平缓.研究认为,该群落物种组成与多样性及主要物种的重要值、平均胸径变化幅度较小,未发生明显波动,主要物种不同径级的更新动态有所差别,但不剧烈,因此整个群落外貌基本保持不变,发展较为稳定.

随着人们对森林认识的不断深入和价值观的不断发展,森林可持续经营已经成为21世纪主要的森林经营方式;森林抚育间伐是森林抚育的主要环节,是实现森林可持续经营的重要手段,本文总结了抚育间伐的发展历史、概念、目的和分类;结合国内外研究现状,综述了抚育间伐对森林林分结构、森林生产力和森林生物多样性的影响,对抚育间伐技术要素的确定提出意见,就中国森林现状总结了森林抚育间伐工作中存在的问题,并提出相应的建议,希望对森林抚育间伐工作有所启示.