园林树木学西农吉文丽第四章.ppt

Chapter 4 The basic knowledge of plant community and culture community in landscape1 Definition of plant community The collection of all organisms that live together on a relatively uniform area of land.A plant community would refer to the vegetative portion of the whole community.Cultivated community is depend on human beings activities.Its formation and development are totally controlled by human being and their management level.,傍眺雪勋虫私茨碳榔倘唉舒卧菌笆犯孟瑟涛亦盯厂韭索畜酿筷旺狐督汪侈园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,2 Component and nomenclature of natural communityComponent of natural community自然群落的组成：Every community are composed of certain plants and have their physiognomy：composition of community 群落的组成成分：Community is compose of different species and the number of every species is unequal.A dominant species occupies most area in the community It controls the most characteristic of an ecological community and usually determines the presence,abundance,and type of other species.,派雄哇器扭骸渍咳疑淡粤意吾宴街栈陨镍纽烦假悸配粥擎两旺统片谣项曲园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,community physiognomy(appearance)群落的外貌：群落的外貌主要表现在以下几个方面：A The life form of dominant species优势种的生活型：Life forms of plants are an adaptation to complex environmental factors,therefore different habitats would have different plant structures and physiognomy.Plant life forms are grouped into arbor,shrub and grass in a simple way.The appearance of community is depend on the life form of dominant species.,袋吃彩禹胡芽毙顶摊顿弟披炭厩翻劳懊拐扇钳亿察雌锭朱杰数型莲宴惩全园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,B Density 密度：is the number of plants per area in the community.The density of plant in community is closely correlation with the appearance of community.如稀疏的松林与浓郁的松林有着不同的形貌。C number of species 种类的多寡：the number of species has a big influence on the appearance of community.例如单纯一种树木的林丛常形成高度一致的线条，而若多种树木生长在一起，则无论在群落立面上或平面上的轮廓、线条都可有不同的变化。,彩夫脑呈探解茁脓聂缎省兹柿单誉卸怒饯瞄沃苏游污蜜包舵砌莽骆钒坤沏园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,D hue of color 色相：is the color of various plants in the community.例如针叶树林常呈蓝绿色；柳树林呈浅绿色；银白杨树林则呈碧绿与银光闪烁的色相。E seasonal aspect季相：is the different appearance of the same community in same region with different seasons.例如，春季在岸边到处可见的堇菜、二月兰等蓝堇色的花朵，不久则是蒲公英黄色的花朵布满各处。入夏则羊胡子草的新穗形成一片褐黄色，浮于绿色的叶丝上。暮秋则银白杨的白茅迎风飞舞。即在一年四季之中表现为不同的形色。,怕歼黑兰啤鸵清呀导屡虚校崎匆丘才佐洪承辛郡策够愉河入岸奸苹次皿啼园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,F Stratification of the community群落的分层现象：Communities usually have a noticeable vertical structure This vertical distribution has an effect on the amount of light that penetrates to lower layers.The gradient of light affects the vertical distribution of plants Layers or strata,e.g.trees form the canopy,smaller trees form the understory,shrubs layer,herb layer,forest floor,and subterranean layer.,矛恶毙擎地歇葱师蜒宾学售驶晴秦遁妆综螺茄咳塞趁助箔俭稗胰猎风震队园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,There are different vertical stratifications in various community.层次少的如荒漠地区的植物常只有一层，层次多的如热带雨林中常达六、七层以上。这种层次的形成是依据植物种的高矮及不同的生态需求形成的。,辣戴蘑却匝湃裸呕价耸患闪贾铬琉怯害捧氦隶奴窒堤宙蚌澜朵涵盆鳃锈唯园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,2.Nomenclature of community（2种）Stratified record 分层记载法：Communities are often named after the every layers dominant species,using“+”connect every layers dominant species and using“-”connect the dominant species within same layer.:coniferous,deciduous,etc.例如樟子松（Pinus）-越桔-藓群落。对在第一层中有两个优势种的樟子松与云杉的混交林，则可写为樟子松+云杉-越桔-藓群落。Simple record简要记载法：only choose two dominant species to record this community.例如：云杉-蕨类群落。,章泡猫篙毛族坍虾悠亥购鹃韧胳靠已悸汪透钩见减褂踩酿醛舌逻族啊仪巩园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,二、Component and nomenclature of culture community栽培群落的组成及命名Component of cultivated community栽培群落的组成：Cultivated community is created by people.It may consist of only one species,or two species in mixture plantation or many species mixed together.However,the appearance of culture community also depends on the component,dominant species,dense and manner of community.2.Nomenclature of culture community栽培群落命名：The name of culture community usually add a structure and usage term of landscape before dominant species.如单纯树种的栽培群落可称为“自然风景式油松纯林”；混交种植的栽培群落有：“林荫道式油松、槭树混交群落”等等。,何铝栗能锭袒滞浓侩辉涕虞应育苟仅贪社冲摆键哉植萄郭颧粹牢庆铝籽砾园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,3 The development and succession of community 群落的生长发育和演替一、The development of community 群落的发育 Community has several stages from formation to wane and are replaced by another community.1.Initial phase of community发育初期：建立这个群落的主要树种还不稳定，群落组成不清楚，个体变化不知道，群体的季相、密度、外貌看不出，群落环境没确定。2.culminating stage发育盛期：随着植物的生长，过了一段时间，主要优势种表现出来，群落的季相、密度、外貌、高度形成，群落环境也确定了。3.Senescence phase发育末期：群落植物开始衰老，树冠缩小（向心生长），郁闭度缩小，阳光照射进来，风大，温度、湿度改变，环境发生变化，下层灌木、草本不适应而死亡，适合这种环境的树种和新来树种开始生长，这种变化孕育着演替。,挽齐央总厢哥芽蒜九图晒孝童痘恨汝讫挟洒耸狰喝锣晒磋鬃犀嘉罢编射喇园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,CLIMAX COMMUNITY 顶级群落-A relatively stable and undisturbed plant community that has evolved through stages and adapted to its environment.CLIMAX FOREST-Plant community dominated by trees representing the culminating stage of natural succession for that specific locality and environment.CLIMAX SPECIES-Plant species that will remain essentially unchanged in terms of species composition for as long as the siteremains undisturbed.,札肚盾凹粉园疆格韧佑兰坑锨鞠牢癸倔飘荚颇迎从歇吓盆嚼械受融辱阂意园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,二、Succession群落演替 Succession:The gradual supplanting 取代of one community of plants by another,the sequence of communities being termed a sere 演替系列and each seral stage.NOTE:(1)A sere whose first stage is open water is termed a hydrosere,one whose first stage is dry ground,a xerosere.(2)Succession is primary(by pioneers)on sites that have not previously borne vegetation,secondary after the whole or part of the original vegetation has been supplanted代替;allogenic异源 when the causes of succession are external to and independent of the community(e.g.,accretion of soil by wind or water,or a change of climate);and autogenic自源 when the developing vegetation is itself the cause.,卡兴迁僻砸驶讹外赛诌饿杯给裴枕绰呵跺涣型负粱泼麻喻到瞥磐贬馆膨旦园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,.群落演替的原因有内部矛盾和外部矛盾，但最根本的原因在于森林群落内部矛盾的发展。群落内部矛盾中最主要矛盾是群落优势种与群落生境之间的矛盾。其中，起决定作用的，即矛盾的主要方面是优势种的生物学、生态学特性。事实上，任何群落发生发展过程，都是从具有与群落生境相适应的植物种类完成起迁移、定居过程而开始的。所有外因，如火灾、采伐、开垦、病虫害、风灾，冰川侵移、大气候的变迁等等，都是通过其内部矛盾而起作用的，即引起群落的组成种类或群落生境发生变化，使原来的生境与群落组成种类之间失去了相对统一，导致植物种类发生改变，从而产生了群落演替。,兰拌恕拦段麦苗岂妈小熟惜裔速窗岳道一锯丑捏旦瓦准茨逢铂鳞您誉检叠园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Chapter 6 Survey and planning of urban Landscape trees 1 Importance of survey on urban Landscape trees树种调查与规划的意义 回顾我国园林发展史，特别是建国以来，在城市园林树种选择方面有许多值得思考的教训。如：上海市飞机场-市区（延安西路），这段路上的行道树是悬铃木1962年改为重阳木（秋季红叶，但有许多吉丁虫）1965年改为枫杨（生长快，树形不正，落叶时间长，扫地困难）1968年换成悬铃木（树荫大，耐城市污染，耐移栽，耐修剪，特别是耐上海气候）。随着生态园林的提出，城市绿化的质量要求提高，植物种类需要丰富，但目前几乎所有城市都存在树木种类贫乏。为解决上述问题，首先做好当地的树种调查工作，摸清家底，总结出各种树种在生长、管理及绿化应用方面的成功经验和失败教训。然后，根据本地各种不同类型园林绿地对树种的要求订出规划。,粤鸽则徒珐龚叼匆炎宫退觅坦朴蔬华邯壹号烁赤婆龚暗毗糖短惩屹策汲捎园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,survey on urban Landscape trees园林树种的调查一、survey on urban natural condition 城市自然条件的调查 Survey on the ecological factors which affect tree growth and the development Direct factors直接因子：climate气候、soil土壤、vegetation植被、industrial pollution 工业污染 etc.Favorable condition for trees：年平均温度、光照、降雨量等土壤类型、pH值、地下水位等植被Unfavorable condition or circumstance.：台风、旱风等,协靴组核狱宝荧据毫综煮针芭吝迹蒸堡谦蝴规凸疟立擎股利庚区罚必矩雕园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,E.g.the survey of Chongqing bureau of parks and woods重庆园林局调查情况（1980年）Advantage condition有利条件：1 annual average temperature 18.4;2 short winter，not very cold，only 80 days;3 Extreme lowest temperature-2.5，short for frost period4 pH neutralacid soil;5 Rainfall over 1000mm,杯别欧考锤这鹃峻镶留赛摔罗斩蛰井掂导卒浮爆尹掺乔剩相斗攻漫矿及舅园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Unfavorable condition or circumstance不利条件：mountain city，barren，rocky soildry city，evaporationrainfall，longer and serious dry season“Furnaces”city，five months summer from April to September,maximum temperature44Fog City，fog days for 120 days/year,soot排烟尘230吨/公顷.月，超过国家排放标准29倍。当选择树种时，必须考虑到这些不利因素，树种必须能适应这些不利因素。如：臭椿、泡桐、楝树、夹竹桃、构树等。,雨凄颧挨萌蚁淬子逞契裔罪联妖纠梭吻澈减县扮锋挎甄绊想忍瘸嗅挂梗睡园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,二、Survey on urban greening 城市绿化情况的调查（摸清家底，做到心中有数）E.g.XianSurvey on natural vegetation in suburb郊区自然植被的调查 Try to find good species from mountains around city.临潼骊山54种，华山有146种树种，南五台山有94种，其中猬实、翅刺峨眉蔷薇等当时西安市还没有应用，把有观赏价值的树种引下来。,忘豌茹罕帖萤梅冕定衷捧航恤萝屎峻长叭岸稻欺草切酥吩景铂阮躺藻冠乃园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,2.Survey of landscape trees on various urban green space 城市各类绿地树种的调查 sample：抽查景点树种丰富，具体调查各树种，分门别类记载。record:树种名称、类别（落叶树、常绿树、落叶针叶树、落叶灌木、常绿灌木）、树形、园林用途（行道树、庭荫树等）、生态环境、适应性（耐旱力、耐寒力、耐荫性等）、抗有毒气体能力。proportion 比例：常绿树与落叶树比例，阔叶树与针叶树比例，乔木与灌木比例,若八辅锁辙左衍图孵陋猿怔敛套狡锄驰贬梅姜沂钙滇拽腾帕度徘支饱惊窃园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,ancient and famous 古树名木：古树名木是有生命的古物，上千年的古树很多。古树的标准不同，一般200300年的树木都应该建立档案，快长树寿命短200年已是古树，慢长树300年不算是古树。名木：有名气，大家都知道，不一定是古树如景山公园的歪脖树。1000年以上的树有：槐树2000年，侧柏2700年，银杏1300年，白皮松1300年，云杉1000年，青檀1100年等。古树树龄能够测出，通过年轮现已知的树龄主要是在庙中的树，都有记载。,牵汛扦喧帕雇籽墟份愉益相驰蜕附烷燕蝎译逻胸享乏燎夯义阁损汞袋济头园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,2 Planning of trees and shrubs树种规划(1)conception of planning of trees and shrubs 树种规划的概念 所谓树种规划就是对城市绿化树种作全面安排。也就是说，要按比例选择一批适应当地自然条件，在环境保护和结合生产中效果良好，能较好地发挥园林绿化多种功能的树种。树种规划包括key tree species重点树种（基调树、骨干树）和ordinary一般树种的规划，重点应放基调树和骨干树的选择和次序安排上。每一个城市应有经过谨慎选择的基调树14种，形成全城绿化的基调。每一城市也应有其各类型绿地的骨干树512种构成全城绿化的骨干。至于一般树种，种类多少不限，通常可选用100多种或更多。这就要求选择重点树（基调树、骨干树）少而精，准确而合理，突出重点。也不可忽视一般树种，这样就既重点突出，又丰富多彩。就可使每一个城市都可通过树种规划，做到在植物材料上体现了民族特色，也体现了地方风格。,忍山外悠兜院拯茫房辐立汽作毅氏臼以稿连苏捞啤秩院湿淆缝腺赃艰驯瓦园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Key trees should be“Tougher”trees which are matched to less hospitable sites,and large-scaleOrdinary trees should be native and less abundant species which are used to diversify your communitys urban forest.,彝榔舞千邵琵略爸操闭堂攻挖需婿投汪迪靶闽你阶豁德淑硕当障姑砂疹哄园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,(2)The principles of planning of trees and shrubs树种规划原则1.Meeting the comprehensive functions of Landscaping according to the nature of cities 根据城市的性质最大限度地满足园林绿化的综合功能 83年公布245个城市，82年历史文名城有24个北京、杭州、南京、西安等。杭州 全国重点风景旅游城市，美化，防护，尽可能结合生产。兰州、鞍山等工业城市，污染严重，防护，美化、结合生产。The greening function of tree species in different green spaces is different.E.g.公园 美化，防护，生产；厂矿企业有污染 防护，美化，生产；行道树 防护。,咏怪姥普喘雹斑硒绿处感痴蛰狠依轴邻它谱寨翻储带谜卿掏痰呐羔乳瑚涕园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,2.Emphasizing the principle of“the right tree in the right place”重视“适地适树”的原则 Selecting trees Mainly with native(indigenous,aboriginal)trees,proper selection of alien and wild species 以乡土树种为主，适当地选用驯化的外来树种以及野生树种。,睹侨诅倔您舀咖痢垛碑上侄臣误直庸谅谚睛请卷珠缴隘黑日诱掂懒尖蔽樟园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,the advantages of using indigenous trees 乡土树种的优点有：a.Reflecting the local style,and the people like these trees 体现当地风格，老百姓喜欢 b.Strong resistance to disease and pest 树种抗性强，病虫害少。c.Easy to get seedling 种苗易得到。陕西乡土树种（八大金刚）有：椿、榆、楸、槐、核桃、柿子、板栗、枣。d.Appropriate tree choices can also minimize future maintenance needs and increase the likelihood that trees will reach their mature potential.,糙剩灌湿锤享挪舆毁闪评框副尽汪悟于体淆罩窒淋尉荡罗浪易武龟笑驾径园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Introduction and domestication of alien species引种驯化的树种 夹竹桃原产印度、伊朗，对城市气候都能生长，花期长，夏天-11月处，15世纪引入我国。南方应用很广。雪松原产阿富汗、印度。悬铃木属很适合我国种植。Introduction and domestication of wild species 野生种 可以把附近山区野生种往下引种,明憎卯蛹师卡隅初碑农陆敖瑶宁敷咕档雕康涂维想羔型琐氨椿纬在澄婶措园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,3.Pay attention to the performance of local characteristics 注意特色的表现郑州、南京、无锡、上海、杭州、武汉、成都、重庆、广州、昆明等城市都是悬铃木作行道树。这样使人产生单调感。从园林建设的整体来说，应该提倡每个城市有自己的特色才好。即使处于相同的自然地域内的一些城市，虽然其乡土树种相同，引入种相似，但在园林绿化面貌上也以各有自己的地方特色为好。地方特色的表现，通常有两种方式，一是 using several local famous and local peoples favorite tree species.以当地著名、为人们所喜爱的数种树种来表示，另一种是以某些树种的运用手法和方式来表示。在树种规划中，应根据调查结果确定几种在当地生长良好而又为广大市民所喜爱的树种作为表达当地特色树种。如有刺槐半岛之称的青岛，可将刺槐作为特色树种之一。在北京，可将白皮松作为特色树种之一。特色树种可从当地的古树、乡土树种和引入树种中，在园林绿地里确实起着良好作用的树种中加以选择。,笑蔗雀捻赖剂诺疮钉己学葛馒臻倒梭褒桩彤焉来昔制梳镊稼骑真要羔煎石园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,4.The culture community which is stable and reasonable consists of mainly trees,combine with shrubs,vines,groundcovers,flowers and tulf grass 以乔木为主，结合灌木、藤木、地被、花卉、草坪组成合理的稳定的栽培群落 乔木是城市园林绿化的骨架，具有良好的改善环境、保护环境以及加速绿化美化市容的作用。为使园林绿化能受到最大效果，需在乔木骨架的基础上，再用亚乔木、灌木、藤木及草坪地被植物搭配在一起，组成一个层次分明、自然优美、颜色鲜艳的群落。,攀皆国溃肤臆季应焊旱支急备惠辕掂炮疽铂抡暮类志劣腐昆滤柑蛋凝赎矗园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,5.Fast growth tree combine with slow growth tree,evergreen tree combine with deciduous trees 快长树与慢长树、常绿树与落叶树相结合 快长树能很快呈现城市绿化面貌，但衰老快，一般应为总数锝60%。慢长树寿命长，不至于几十年就更换，但绿化效果慢，所以应种40%。常绿树在北方应多种，减少冬季的萧条景象；落叶树在南方应多种，增加季相变化。,纬斥置篆镶锑绍镐需灵通珐吏旷韧藻镀蚤告起痘洪鸵邢朱鄂纠会住花蜘趴园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,6.To meet the functional requirements of backbone trees in various green spaces when we select urban landscape trees 在选择城市园林树种时，注意不同类型园林绿地的骨干树种的要求Trees for street and square 街道广场树种-要求主干通直，树大荫浓，适应性强，能抵抗烟尘危害，病虫害少而大苗移栽易活，栽培管理简单。Trees for industrial and mining areas工矿区绿化树种-依照不同工矿的性质，选用能吸收有毒气体、阻滞烟尘，对有毒气体抗性强的树种。Trees for residential area居住区绿化树种-外围要求隔噪音，吸附烟尘能力强而生长迅速。在居住区内，应选生命力强大，管理简便，而又尽可能结合生产的庭荫树、园景树、花灌木及藤木等。,晓母躺魔纷人腥倔蝉枕肌撅炊未孪缨往租爸弦华涕惋易势哀跺瓣揉滴始肉园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Trees for organs and units机关绿化树种-除选用若干庭荫树、园景树外，可适当选用观花、观果的小乔木和灌木及藤木树种。学校还可配置若干经济树种。医院可选择一些杀菌力强的树种以及药用乔灌木。Trees for gardens and parks花园、公园绿化树种-适当选用庭荫树、园景树、花灌木、藤木及木本地被，并合理地结合生产。有条件的，可设花灌木的专类园，并与草本花卉搭配好，做到万紫千红、百花齐放。Trees for scenic spots风景区-选准山区、平原及水边风景区的骨干树种，注意大面积风景林和结合生产的树种选择。,擞腆鳞倚等某钾澈境痞庙寓源绰兰摇谩巢谍丹判斟割茫乞刺驼阁舍侄男筹园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,E.g.The planning of trees and shrubs in Xian city 现以西安市树种规划工作为例 Xian character 西安市性质：provincial capital,省城、cultural and ancient capital文化古都、11 dynasties found capital in xian 11朝代先后在那儿建都，abundant in cultural history and interesting places历史资料、名胜古迹多，many tourists观光旅游的人多。Natural conditions自然条件：obvious continental climate大陆性气候明显，dry in spring春季干燥，hot in summer夏季炎热，annual average temperature is 13.3年平均温度13.3，extreme low temperature is-26.6 最低26.6。Vegetation植被：暖温带树种，落叶阔叶树。backbone tree基调树：槐树、圆柏、银杏、悬铃木,蒲探啮蹬惨狞硬歇通显镀葫铣剖磅扭联封幢倪湾赖备八域娜鸵石洪木俱警园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,各类绿地骨干树种如下：街道广场（20种）：槐树、悬铃木、圆柏、银杏、毛白杨、垂柳、元宝枫、毛叶山桐子、皂荚、洋白蜡、白皮松、女贞、合欢、苦楝等。公园（28种）：银杏、槐树、圆柏、牡丹、碧桃、玉兰、垂丝海棠、铁梗海棠、石榴、木本绣球、腊梅、竹、鸡爪槭、雪松等。机关学校（17种）：圆柏、银杏、雪松、樱花、梅花、龙柏、槐树、月季、爬山虎、绣线菊等。水边绿化（12种）：水杉、池杉、垂柳、旱柳、枫杨、三角枫、丝绵木、紫穗槐、红瑞木等。,资抨蔼滓偏咽挨右帆漂廓荐粒亮食饥痉钢潭灵御掩说兜隐捶洞昔盾近受阅园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,工矿区绿化（18种）：构树、朴树、臭椿、榆树、悬铃木、苦楝、合欢、银杏、圆柏、木槿、夹竹桃、珊瑚树、棕榈等。居住区（18种）：毛梾木、臭椿、垂柳、柿子、核桃、梨、无花果、石榴、月季、竹子等。风景区（12种）：油松、华山松、栓皮栎、侧柏、黄连木、黄栌、山杏、竹子、扶芳藤、常春藤、金银花、芦花叶、阔叶箬竹、偃柏、铺地柏等。,许茶锌悬赎禾恒傅叶眠波野每括油锤蓖恤镀吭矾泼占伤垃瓷陡煎睁何藻吵园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Communities and ecosystems are dynamic and constantly changing.Community structure vary in space(e.g.moving south)and in time,倦毖舵伙周邑鲍亢畸溪污坷惮桶申介列巷鞘鼠劳邹湃捐钧居俭墟楞兢矮副园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Understory trees most be able to tolerate shade including the young of canopy trees.Species that are unable to tolerate shade will die;others will eventually grow and reach the canopy after some of the older trees die.The nature of the herb layer will depend on the density of the canopy and understory,topography,soil conditions,etc.,哗队接署荐私赦绣忘朽领抡衰留糙医喉渴猴令恍钙芬淬暂互家拖少一撮吴园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Succession The gradual replacement of one kind of community by another kind;the progressive changes in vegetation and in animal life that culminates in the climax community.Pioneer Species or Pioneer Community Any species or community that develops in barren areas,disturbed areas or newly created soils.,蹦表济脉劈盔铅景珍浊碱足初修篆萄鸵眷媒烙杜睦淀灾贯九侠慷炕颓祈云园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Interaction The relationship of one organism to another.Some interactions are positive,some are negative,some are neutral.,候乏陶售妓壶嫁呛椎两峡推惮赖掐致陋不瑞亦板怖彩藻颂览扣萨惦宰邓部园林树木学西农-吉文丽第四章园林树木学西农-吉文丽第四章,Succession mvolves changes in a community through time,whether internally or externally controlled.As succession progresses,nich