云南的硬叶常绿阔叶林——古地中海残余植被

云南从干热河谷到寒温性山地广泛分布有一类常绿、阔叶、以壳斗科栎属植物为乔木优势种的森林植被，由于其独特的生态特征显示了与现代地中海地区硬叶栎林的相似性，而在群落的外貌、结构、特征种、地理分布等方面却与云南的亚热带常绿阔叶林有明显区别，因此被称为“硬叶常绿阔叶林”,它是在喜马拉雅隆升中因适应新的环境而发育的一个特殊植被类型。该植被的优势树种具有古地中海地区渊源，但在分布上大多为我国西南地区的特有种。硬叶常绿阔叶林除优势树种为硬叶栎类以外，其他种类与同域天然植被的物种组成基本一样，并没有一个独特的植物区系。硬叶常绿阔叶林群落结构简单，典型的硬叶常绿阔叶林群落有清楚的乔木、灌木和草本3个层次，而在生活型上，寒温性山地的群落以地面芽植物占绝对优势，干热河谷的群落以草本植物占优势。在中新世以前，硬叶栎类植物出现在湿润的热带-亚热带性质的古地中海常绿阔叶林里，直到上新世以后，现代的地中海式气候形成，适应干旱的地中海植物区系出现，并随喜马拉雅隆升，硬叶常绿阔叶林才从原先的热带-亚热带常绿阔叶林演化产生。     

云南常绿阔叶林的类型和特点

常绿阔叶林是指由壳斗科、茶科、樟科、木兰科的常绿阔叶树种为主组成的森林,但不包括常绿阔叶的热带雨林和常绿阔叶的山地硬叶林。常绿阔叶林主要分布在亚热带较湿润的气候条件下,所以也称之为“亚热带常绿阔叶林”。我们在植被文献中所见到的“照叶林”、“樟栲林”、“常绿栎类林”、“亚热带山地雨林”、“亚热带常绿季雨林”等等,都属于这一类森林范围。当然,它也应包括含有温带落叶成分的常绿阔叶林。     

广西常绿栎林的分类

常绿栎林属于常绿阔叶林的一个群系组,在广西有平脉栎（Quercus kerrii Craib)林、绒毛栎（Q.gomeziana A Camus)林、蝶斗栎（Q.disformis Chun et Tsiang)林和华南栎（Q.edithae Skan)林4个群系。前两者见于桂西北干旱区域,后两者分布在桂东湿润地区。这些地区常绿栎林群落划分、种类组成和动态变化的阐明,可为科学经营管理提供依据。     

广西落叶栎林的分类研究

广西的落叶栎林属亚热带落叶阔叶林的一个群系组, 常见有栓皮栎林、麻栎林和白栎林３ 个群系。主要论述其类型划分和生境特点, 为其经营管理和合理利用提供基本材料和依据。     

广西石栎林分类的研究

石栎林属于常绿阔叶林的一个群系组,在广西见有粤桂石栎林、华南石栎林、烟斗石栎林和长果石栎林4个群系。前者主要见于中亚热带地区山地,后三者分布在南亚热带范围的山地。文中主要论述其群落分类、种类组成和动态变化,为其科学管理提供基本资料和依据。     

西藏壳斗科的地理分布

在野外考察、分类清理和修订的基础上讨论了西藏壳斗科的地理分布。自然分布的西藏壳斗科植物,共３属３３种,集中分布于藏东南的河谷地带和喜马拉雅山脉的聂拉木县,印度栲、刺栲、喜马拉雅石栎和西藏石栎是这些地区海拔２００米以下群落建群种;通麦栎、俅江栎和薄片青冈是西藏海拔１８００－２５００米地段森林植物被的建群种;硬叶高山栎类则是海拔２５００米以上硬叶常绿阔叶林及高山灌丛植被的建群种。种的区系成分分析表明：     

子午岭辽东栎林林窗主要树种更新生态位

在对子午岭林区辽东栎林中54个不同大小林窗调查的基础上,分析不同树种的更新生态位,结果表明：辽东栎林中不同树种的优势度随着林窗大小级的变化差异较大;根据各主要树种在不同大小级林窗内生态位宽度的变化,可分为生态幅度宽、中等、较小和狭小4类,其中大多数树种属于狭小生态幅宽度;辽东栎林中各主要树种在不同大小级林窗中的生态位重叠度较小,其中在100～200 m²林窗中的重叠度最小;在100～200 m²大小级林窗中,实生和萌生辽东栎的重要值和生态位宽度均大于0～100和200～300 m² 2个大小级林窗中的辽东栎,说明100～200 m²大小级林窗可为辽东栎的天然更新提供场所。     

陕西省典型天然次生林和人工林生产力对气候变化的响应

本研究利用基于过程的动态植被模型LPJ-GUESS模拟并分析陕西省栎类林和刺槐林在未来时期(2015—2100年)不同气候情景下净初级生产力(NPP)和净生态系统生产力(NEP)的动态变化和趋势.结果表明: 与基准时期(1961—1990年)相比,未来时期陕北地区栎类林和刺槐林NPP将分别下降4.9%～29.5%、22.5%～56.2%,而在关中和陕南地区栎类林和刺槐林NPP将分别升高13.0%～49.0%、21.3%～62.9%; 未来时期,不同情景下的栎类林和刺槐林NPP均表现为RCP_2.64.58.5;未来时期,2种不同类型森林在陕北、关中、陕南3个分区均表现为碳汇,栎类林在陕北和关中地区的碳汇功能更强,而刺槐林在陕南地区的碳汇功能更强;3个分区刺槐林在不同RCP情景下NEP的变化幅度均大于栎类林.     

古地中海退却与喜马拉雅-横断山的隆起在中国喜马拉雅成分及高山植物区系的形成与发展上的意义

横断山-喜马拉雅植物区系的开端是在晚白垩纪和早古近纪(早第三纪).古植物资料表明在古近纪初期横断山-喜马拉雅植物区系是同古地中海沿岸一致的以照叶林为主的暖湿植物区系.古近纪后期和新近纪(新第三纪)以后古地中海气候逐步旱化,原来的暖湿植物区系在地中海地区逐步消失,而在横断山及喜马拉雅和东亚其他地区得以保存和发展,现代横断山及东喜马拉雅的亚热带森林即是其后裔.古近纪中期以后由于古地中海的逐步退却,气候变得干旱,原暖湿植物区系逐步被现代旱生的地中海植物区系所取代.新近纪以后,旱生的现代地中海植物区系由于喜马拉雅和横断山的隆起而转向适应高山环境,逐步分化形成了现代的中国-喜马拉雅成分.横断山-喜马拉雅地区硬叶高山栎林的起源;铁筷子属,绿绒蒿属,芒苞草属,假百合属及马桑属的地中海、喜马拉雅-横断山间断分布的形成便是古地中海植物区系残遗的体现;黄花木属、独一味属等众多中国喜马拉雅成分就是古地中海祖先的后裔.这些代表类群的分析研究表明现代的喜马拉雅-横断山的高山植物区系以及中国-喜马拉雅成分中有相当的一部分是起源于新生代旱生的地中海植物区系.     

关于泰岭及陕北黄土高原区辽东栎林的初步研究

由于辽东栎从第三纪以来,经过多次冷、暖、干、湿气候波动的影响,表现出气候上的广生态幅特点,是它形成现代分布区的基础,既可在黄土区接近草原地带形成水平地带性植被,又能在秦岭形成垂直地带性群落。秦岭辽东栎林的种类组成、层次和层片结构以及生态类群等方面都比黄土区复杂。今后辽东栎林在秦岭和黄土高原现在的分布区内,仍是最稳定的群落。     

中国北方蒙古栎林起源和发展的初步探讨

古生态学的研究显示 ,栎林 (包括蒙古栎林 )在华北地区和东北地区的分布在地质历史时期不是一成不变的 ,其优势度也呈现上下波动 ,栎树优势度的增减是由于地质历史时期气候的变化造成的 ;蒙古栎的起源时间可能不早于上新世中期 ,蒙古栎林的起源也应不早于上新世中期。蒙古栎林的起源原因有 2种 ,即火与人类的反复砍伐。火是原生性质蒙古栎林在地质历史时期存在和扩散的根本原因 ,过度的人类活动 (主要是反复砍伐 )是促成现在蒙古栎次生林占优势地位的主要原因 ,这是由蒙古栎这个树种的生物学特性决定的 ,在没有外界因素的干扰和火减少的情况下 ,蒙古栎在演替过程中逐渐被耐荫的树种所取代 ,但是在中国北方 ,由于人类活动的加剧 ,蒙古栎林的优势度有增加的趋势。     

桂西地区南亚热带落叶栎林群落组成及物种多样性研究北大核心CSCD

落叶栎林是桂西地区南亚热带的典型次生林,也是该区域落叶阔叶林的重要群系组。该研究采用典型样方法对桂西地区落叶栎林群落进行调查,分析了该区域落叶栎林群落的物种组成、区系成分、物种多样性特征及其与地形因子的关系,为桂西地区南亚热带植物多样性保护与恢复提供依据。结果显示:(1)研究区落叶栎林群落维管束植物共计269种,隶属80科178属。(2)种子植物区系以热带成分为主,同时表现出一定程度的温带过渡性质。(3)聚类分析表明,调查的落叶栎林群落可分为云南波罗栎林、栓皮栎林、白栎林、麻栎林4种林分类型,其中以白栎林群落的物种多样性最高,且灌木层的物种多样性显著高于乔木层和草本层。(4)RDA分析显示,落叶栎林群落不同层次物种多样性的差异受地形因子的影响,多样性指标与经度、纬度、海拔之间具有明显的相关性(P<0.05),其中乔木层物种多样性主要与经度、纬度呈显著的相关性,灌木层物种多样性与纬度、海拔相关,草本层物种多样性与经度、纬度、海拔之间均有相关性。     

黑龙江省不同地点蒙古栎林生态特点研究

通过对黑龙江省６个地点的天然蒙古栎林的结构和更新特点的分析,蒙古栎林可划分为不同特点的蒙古栎群落,即纯蒙古栎群落、蒙古栎桦树群落、蒙古栎槭树群落、蒙古栎红松群落和蒙古栎松混交林群落,其演替趋势如下：红蒙古栎群落、蒙古栎桦树群落至蒙古栎槭树落、蒙古栎红松群落,再至蒙古栎红松混交林群落,蒙古栎群落类型的多样性主要反应群落不同的演替阶段,造成蒙古栎群落多样的原因是人类活动和自然因素作用的结果,随着群落的演替,蒙古栎的优势地位逐渐被消弱,乔木种类丰富度增多,草本种类丰富度增多;蒙栎的相对密度下降,林内环境由于干燥逐渐变中性至较湿润,蒙古栎幼苗和幼树在总幼苗和幼树中所占的比例下降,耐荫物中色木槭等的幼苗和幼树所占比例上升;在演替过程中,蒙古栎分布格局－聚集分布的聚集程度逐渐降低,并向随机分布的方向发展。     

锐齿槲栎林的天然更新——坚果、幼苗库和径级结构

对四川茂县地区的锐齿槲栎(Quercus aliena var.acuteserrata)天然次生林进行研究,发现(1)坚果完好比例约在14%～26%之间,完好坚果的发芽率和发芽势都比较高,但在天然状况下能够留存到隔年5月的坚果几乎没有.因此,实生幼苗的天然补充就受到了严重的限制.(2)林缘的幼苗密度低于所有其它生境的(p＜0.05),林中的幼苗密度最高,和林窗的比较有显著差异(p＜0.05),而和灌丛的比较则没有差异.在灌丛幼苗密度和林中以及林窗的比较都没有差异.动物对坚果的取食速度则是林中的最慢(10.0%),林窗和林缘的相同(分别为61.1%和66.5%),都比较快(p＜0.01).(3)林中的幼苗在小于100 cm的各高度内都有大量分布,说明在林中树冠下幼苗是可以长期存在的,在幼苗和种子阶段的锐齿槲栎可能是耐荫的.(4)在林中缺失幼树,在林缘则有包括幼树在内的完整的更新大小系列,表明林缘也可以成为更新的关键地点.(5)在栎林的每一个大小级别上,萌生个体和实生个体都按各种比例伴生,说明导致萌生的干扰一直在发生,并可能在森林的更新中扮演重要角色;也说明该地区的锐齿槲栎林由萌生和实生起源的个体混合组成.     

黄土高原主要森林类型自然性的灰色关联度分析

为了解陕西黄土高原子午岭林区主要森林类型的自然性,以油松林、辽东栎林、白桦林、山杨林和侧柏林等5种森林类型为研究对象,通过0-1型变量聚类,较为客观地提出了森林群落各个演替阶段的植物组成,并计算出了各自的群落顶极适应值;采用层次分析的方法,得到群落特征指标权重,然后利用灰色关联分析方法,得到了各个森林群落的灰色关联度。研究结果表明,黄土高原不同森林类型的群落顶极适应值由大到小依次为辽东栎林(Quercus wutaishanica)8.37,油松林(Pinus tabulaefomis)8.16,山杨林(Populus davidiana)7.89,侧柏林(Platycladus orientalis)6.88,白桦林(Betula platyphylla)6.87;关联度由大到小依次为油松林1.143、辽东栎林1.085、侧柏林0.893、白桦林0.849、山杨林0.789。油松林和辽东栎林的灰色关联度较高,是这一地区较为稳定的理想森林类型,侧柏林和白桦林的关联度居中,山杨林最小。辽东栎林和油松林属于该地区的顶极和亚顶极群落类型,白桦林和侧柏林属于演替过渡类型,山杨林为演替阶段较低的森林类型。用灰色关联度的方法能够定量地分析森林群落的自然性,研究结果对森林近自然经营、林分改造有一定的应用价值和科学意义。     

Distribution of oak forests in Eastern Europe over the last 13000 years

The dynamics and distribution of oak forests on the territory of Eastern Europe over the last 12500 years have been studied. The basic materials used in this study are spore-pollen diagrams converted into the PALAEO database. As a result of this study, a series of maps describing the paleohabitat of oak forests with a 500-year increment has been constructed. Different structures of the paleohabitat of English oak (Quercus robur L.) and the basic forest paleocommunities including this species have been identified and described. The main migration pathways and refugia of oak forests have been determined, including the Volynskaya and Podolskaya uplands, the southern part of the Central Russian and Privolzhskaya uplands, Meshchera, Kodry, and the Mozyrsk-Ovruch-Slovechan refugium.     

北京山区的栎林

 本文叙述了北京山区的主要栎林——辽东栎林、槲栎林、槲树林和栓皮栎林的群落学特征。栎林是由温带植物区系所组成的落叶阔叶林。组成栎林的植物以菊科、蔷薇科、禾本科和豆科植物种类为最丰富。在群落结构中有重要作用的植物,乔木层以壳斗科的栎属为主,灌木层以蔷薇科的绣线菊属、李属、豆科的胡枝子属,马鞭草科的荆条属和虎耳草科的溲疏属占有重要地位。草本层常以莎草科的苔草属,禾本科的隐子草属、大油芒属、野古草属和白草属植物为优势种或常见种。栎林的植物生活型谱,从种类成分分析是以地面芽植物为主,高位芽植物次之,地下芽植物亦占一定比例,但从各类生活型植物的优势度分析,显然以高位芽植物占有优势。组成栎林植物的叶级,是以小型叶植物为主,中型叶植物次之,大型叶植物为罕见。就各类栎林种类成分的相似性分析,以槲树林与槲栎林最为相似,辽东栎林与栓皮栎林差异较大。     

Modelling Mediterranean oak palaeolandscapes using the MaxEnt model algorithm: The case of the NE Iberia under the Middle Holocene climatic scenario

The Mediterranean Basin is a global biodiversity hotspot, and oak tree species play an important role in it. Since the beginning of the Holocene (∼11.4 kyr BP), the distribution of forests has not occurred uniformly, resulting in diverse types of vegetation landscapes. In this study, we used a maximum entropy algorithm (MaxEnt) to obtain the ecological niche model (ENM) of two sub-Mediterranean oak species, Quercus pubescens Willd. (pubescent oak) and Quercus ilex subsp. ilex (holm oak), both in the present day in the Iberian Peninsula and within a Middle Holocene (8.2–4.2 kyr BP) climatic scenario in the NE Iberian Peninsula. Moreover, we used the locations of Neolithic archaeological sites containing anthracological data to analyze the relationship between human occupations and oak habitats. Our results suggest that the two oaks have responded differently to the climatic conditions that have occurred, and show changes in both potential distributions. The palaeolandscape vegetation map shows a denser vegetation cover in the lowlands and a more open landscape in the highlands, with a higher dominance of Quercus pubescens in the septentrional areas, while Quercus ilex was more restricted to certain coastal areas. Temperature and precipitation factors, mainly seasonal climatic conditions, have had a greater impact on the distribution of vegetation than other factors. We found a good overlap between the ENM of the two oaks and the locations of the Neolithic sites analysed, and determined that the distribution of Neolithic archaeological sites is not random. The Neolithic populations in the study area depended heavily on the resources of the deciduous and evergreen sub- Mediterranean forest, although they also exploited the resources of the mountain pine forest. Neolithic sites distribution suggests that Neolithic human groups were aware of the potential of forests and probably gathered woody resources in their surroundings.     

Forest vegetation of the Himalaya

This review deals with the forest vegetation of the Himalaya with emphasis on: paleoecological, phytogeographical, and phytosociological aspects of vegetation; structural and functional features of forest ecosystem; and relationship between man and forests. The Himalayan mountains are the youngest, and among the most unstable. The rainfall pattern is determined by the summer monsoon which deposits a considerable amount of rain (often above 2500 mm annually) on the outer ranges. The amount of annual rainfall decreases from east to west, but the contribution of the winter season to the total precipitation increases. Mountains of these dimensions separate the monsoon climate of south Asia from the cold and dry climate of central Asia. In general, a rise of 270 m in elevation corresponds to a fall of 1°C in the mean annual temperature up to 1500 m, above which the fall is relatively rapid. Large scale surface removals and cyclic climatic changes influenced the course of vegetational changes through geological time. The Himalayan ranges, which started developing in the beginning of the Cenozoic, earlier supported tropical wet evergreen forests throughout the entire area (presently confined to the eastern part). The Miocene orogeny caused drastic changes in the vegetation, so much so that the existing flora was almost entirely replaced by the modern flora. Almost all the dominant forest species of the Pleistocene continue to maintain their dominant status to the present. Presently the Himalayan ranges encompass Austro-Polynesian, Malayo-Burman, Sino-Tibetan, Euro-Mediterranean, and African elements. While the Euro-Mediterranean affinities are well represented in the western Himalayan region (west of 77°E long.), the Chinese and Malesian affinities are evident in the eastern region (east of 84°E long.). However, the proportion of endemic taxa is substantial in the entire region. A representation of formation types in relation to climatic factors, viz., rainfall and temperature, indicates that boundaries between the types are not sharp. Formation types often integrate continuously, showing broad overlaps. Climate does not entirely determine the formation type, and the influence of soil, fire, etc., is also substantial. The ombrophilous broad leaf forests located in the submontane belt (< 1000 m) of the eastern region are comparable to the typical tropical rain forests. On the other extreme, communities above 3000 m elevation are similar to sub-alpine and alpine types. From favorable to less favorable environments, as observed with decreasing moisture from east to west, or with decreasing temperature from low to high elevations, the forests become increasingly open, shortstatured and simpler, with little vertical stratification. Ordination of forest stands distributed within 300–2500 m elevations of the central Himalaya, by and large indicates a continuity of communities, with scattered centers of species importance values in the ordination field. Within the above elevational transect, sal (Shorea robusta) and oak (Quercus spp.) forests may be designated as the climax communities, respectively, of warmer and cooler climates. The flora of a part of the central Himalayan region is categorized as therohemigeophytic and that of a part of the western Himalayan region as geochamaephytic. An analysis of population structure over large areas in the central Himalaya, based on density-diameter distribution of trees, suggests that oldgrowth forests are being replaced by even-aged successional forests, dominated by a few species, such asPinus roxburghii. Paucity of seedlings of climax species, namelyShorea robusta andQuercus spp. over large areas is evident. The Himalayan catchments are subsurface-flow systems and, therefore, are particularly susceptible to landslips and landslides. Loss of water and soil in terms of overflow is insignificant. Studies on recovery processes of forest ecosystems damaged due to shifting cultivation or landslides indicate that the ecosystems can recover quite rapidly, at least in elevations below 2500 m. For example, on a damaged forest site, seedlings of climax species (Quercus leucotrichophora) appeared only 21 years after the landslide. In the central Himalaya, the biomass of a majority of forests (163-787 t ha^?1) falls within the range (200-600 t ha^?1) given for many mature forests of the world, and the net primary productivity (found in the range of 11.0–27.4 t ha^?1 yr^?1) is comparable with the range of 20–30 t ha^?1 yr^?1 given for highly productive communities of favorable environments. In most of the forests of this region, the litter fall values (2.1-3.8 t C ha^?1 yr^?1) are higher than the mean reported for warm temperate forests (2.7 t C ha^?1 yr^?1). Of the total litter, the tree leaves account for 54–82% in the Himalayan forests. The rate of decomposition of leaves in some broadleaf species of submontane belt (0.253-0.274% day^?1) are comparable with those reported for some tropical rain forest species. Because of the paucity of microorganisms and microarthropods in the forest litter and soil, high initial C:N ratio and high initial lignin content in leaves, the rate of leaf litter decomposition inPinus roxburghii is markedly slower than in other species of the central Himalaya. The fungal species composition of the leaf litterof Pinus roxburghii is also distinct from those of other species. A greater proportion of nutrients is accumulated in the biomass component of the Himalayan forests than in the temperate forests. Although litter fall is the major route through which nutrients return from biomass to the soil pool, a substantial proportion of the total return is in the form of throughfall and stemflow. Among the dominant species of the central Himalaya, retranslocation of nutrients from the senescing leaves was markedly greater inPinus roxburghii than inQuercus spp. andShorea robusta. Consequently, the C:N ratio of leaf litter is markedly higher inPinus roxburghii than in the other species. Immobilization of nutrients by the decomposers of the litter with high C:N ratio is one of the principal strategies through whichPinus roxburghii invades other forests and holds the site against possible reinvasion by oaks. Observations on the seasonality of various ecosystem functions suggest that Himalayan ecosystems are geared to take maximum advantages of the monsoon period (rainy season). Most of the human population depends on shifting-agriculture in the eastern region and on settled agriculture in the central and western regions. Either of these is essentially a forest-dependent cultivation. Each unit of agronomic energy produced in the settled agriculture entails about seven units of energy from forests. Consequently, forests with reasonable crown cover account for insignificant percentage of the land. Tea plantations and felling of trees for timber, paper pulp, etc., are some of the major commercial activities which adversely affected the Himalayan forests.