1、 The physical properties of plants An obvious physical property of any plant is its form.planting designers are usually concerned with the mature silhouette* of a plant,but its intermediate shapes should also be considered,particularly when a plant develops slowly. Most plant forms are rounded and m
2、ore horizontal than vertical in shape. Rounded or horizontal shapes are less dramatic than those with vertical emphasis because they are more expected and they more naturally follow the shape of the terrain. Vertical shapes demand attention,even startling the viewer at times. Native plants forms usu
3、ally conform to land forms(see figure 2-1). In mountainous reions the vertical shapes prevail,reflecting the sharp peaks and jagged rock configurations pf the area. Horizontal plant forms are most commom on the plains,and in rolling or hilly terrain rounded plant forms predpminate. Landscape designe
4、rs do well toremeber this,using the natural plant forms of an area in a design and reserving the unusual forms for emphasis. Although the foerm of each plant is unique, there are general classifivations of forms. Trees can be round, columnar,vase-shaped,weeping,pyramidal,or oval. The outline of a tr
5、ee depends on its branching pattern. Narrow crotch angles at the point where lateral branches separate form the trunk cause upright forms, the more rounded forms are caused by wider angles. Shrubs may be round,oval,pyramidal,or oblong；the may be prostrate or creeping. Part of a plants form is the re
6、sult of the growth habit of the plant. In some evergreens,for example,the branches overlay one another. The plants form takes on an irregular line because of this layering.growth habit should always be considered to be an element of form. The best way to study plant forms is to visit a park,arboretu
7、m,or other area where mature are in plentiful supply. Compare the forms closely to classify specific plants and note the minor differences within classifications. Visit to a nursery are helpful for studying the forms of young or intermediategrowth stages of plants. The silhouette formed by a group o
8、f plants is probably the most important contribution of form to landscape composition. The form of plants in silhouette must allow for function(shade,screening,wind protection,enclosure,and so on),while providing pleasing lines at the same time. Stems,leaves,bark,and buds are the physical features t
9、hat determine the texture of a plant. Textures ranging from fine through medium to coarse are visible because of the size and shape of these features and the way light and shadow play off them. Larger leaves,stems,and buds usually create an effect of coarseness. But the number of branches and leaves
10、 and the spacing between them also affect the texture. Thick,tight foliage results in finer texture,while widely separated foliage gives a coarser texture. Patterns of light and shadow depend more upon individual leaf surfaces in a tight,dense shape； in a loose structure,the masses of leaves and cor
11、responding voids dictate light and shadow,causing a coarser than compound leaves of even larger size,and leaves with deep cuts in the margin,like oak leaves,show a finer texture than other leaves ofsimilar size. Plant texture can be felt as well as seen. One good way to study texture is by closing y
12、our eyes and feeling the plants. The leaves,branches ,bark and buds,of various plants all feel distinctly different. Some are smooth,some prickly,some downright thorny；each sensation is apart of the plants textural character. The farther one stands form a plant,the finer its texture will appear. For
13、 that reason,the distance of view must be considered during the textural study of planting design. Color Color results from light penetration,absorption,and reflection. Light rays of variable lengths enter a plant leaf to be either absorbed or reflected. If all light rays are absorbed,none are refle
14、cted back to the surface；the result is the absence of color-or black. If all rays are refiected back to surface, the rays are a mixture of different color rays,which results in a color hue. Light rays produce red,orange,yellow,green,bulue,and violet colors. Blends of these color rays produce all of
15、the primary,secondary,and tertiary hues we see. Intenseity is a meansurement of the quality of the basic color in the blend. Bright greens,for example,are said to be intense. Another measurement of light reflection produces a dark color；a color；a larger amount of light reflection produces a lighter
16、shade. Plants with a dark blue-green foliage reflect large amounts of light. The foliage of most plants is dominated by the green hue, meaning that green light rays are reflected in the largest quantity. Plant foliage colors range from black-green(grayish),to blue-green,to the bright greens,to red-g
17、reens,and finally to yellow-greens. The green predominates because of the presence of the chlorophyll in the leaves. Some leaves turns to yellow or red-orange shades in the fall because chlorophyll is replaced bythe pigments anthrocyanin(red),carotene (orange),and xanthophyll (yellow) in varying amo
18、unts. The prensence of these pigments causes light rays to be bent and reflect differently, so the leaves change color. Colors are warm or cool,depending upon their hue. Warm colors are those ranging from yellow through orange and into the red hues. Colors ranging from green through blue and into th
19、e violet color. Warm colors are bright,inviting,and lively；cool colors are restful and receding,and they are not as conspicuous. Landscaping moods relate most directly to color hues. It is usually the color of a plants foliage that is considered most in the fruit,bark,and seeds also produce colors w
20、orthy of consideration. While the colors in a landscape do not usually clash, good design provides for a better blend. 植物的物理特性 外形 对于任何植物来说， 最显而易见的物理特性就是他的外形。植物造型设计师通常以植物成年后的外形轮廓特征作为考量的重点，但未成熟，在生长期的形态也应该被纳入考量之中，尤其是当一些植物生长缓慢。 大多数的植物的外形是加圆加粗生长的， 圆柱的或水平生长形态的外观比那些主要强调垂直型的植物要少很多想象空间，因为他们更切合人们的期待，更加自然的适应生长
21、地带的形貌条件。，因此树立生长的植物也应该被重视，甚至时不时的 本土植物的形貌通常适应当地的地形地貌，。在山地，垂直形态更占优势，与当地高耸峻峭的山峰和粗犷多样的岩石相得映彰；水平生长的植物外形 在平原 最常见，而在丘陵地带，圆柱状生长的植物最占优势。园艺景观设计师必须牢记应该用本土植物于自己的设计之中，同时保留一些不常见形态的植物作为点缀强调 景观植物的外形各有千秋，但他们基本上是可以被归类于一些基本类型的。比如说，林木可能是圆形的，柱状的， 瓶状的，下垂状的，金字塔状的，或者是椭圆卵状的。一个树木的外部特征 主要取决于它的外部分枝的形态。就好像跨角小的新枝从老枝分出继续生长，最终使得整株株
22、型笔直，而相对较圆的形态则要依靠大角度的侧枝的生长而成。 灌木可能是团状的，有可能是椭圆形的，又有可能是有棱角的锥 形的，甚至于是长方形的。他们有可能被做成匍匐生长的模样或者是蔓生的， 一个植物某部分的形态是其生长习性的结果。在一些常绿植物中，比如树枝互相交错，层次分明，植物的外形呈现出不规则的线条感正是因为这种交错分层现象，所以生长习性应该被看作植物造型形成的因素之一。 了解植物形态的最好的途径就是去参观一些公园，植物园，以及其他种植大量成熟植物的地方。亲身去比较各种形态特征，区分特殊的植物，并且记下各目类间的细小的差别。而参观苗圃则对学习了解幼年期或者生长期的植物相当有帮助 由一组植物组成
23、的植物群的外扩大致是园林景观构 成中最重要的部分了。在整个园林景观中的植物的形态必须在提供优美线条的同时为功能服务 。 茎、叶、树皮、蓓蕾是决定植物纹理质感的物理特征。这些纹理质地特征因着这些部分的尺寸大小，形态特征以及光影变化在其上产生的不同的影响而产生了由触感舒适到一般再到粗糙的变化 大一点的叶、茎和花通常产生给人粗犷感觉的效果，但同时枝叶的数量以及其间的间隙也影响着质感纹理， 稠密紧凑的树叶要有更好的纹理特征，而分隔稀疏的叶子则给人粗犷的纹理质地。 光影的效果 在稠密紧凑的植物上的效果更取决于单片叶子的表面 。在一个稀疏的造型中，交错堆积的叶片以及相对的空间支配着光和影的效果，反而产生了一种比叶量丰富且叶形较大，开裂较深的植物更叫粗犷的效果。就像橡木的 叶子，展现比相同尺寸的其他叶子更好的质感纹理。 植物的质感能被感觉也能被看见的，一个很好的学习了解植物纹理质感的方法就是闭上眼睛去感觉那些植物。 各种各样的植物的叶，茎，树皮和蓓蕾本来就不同。有一些是平滑的，有一些是多刺的，有一些则是 通体布刺的；每一种感觉都是植物质感特性的一部分。 站的离植物越远，植物所显现的特质则越好，因此，观赏的距离理所应当的是植物造景设计中好 好考虑的 颜色 色彩来自于光线的射入，吸收以及反射。各种波长的光线射入叶片当中或者被吸收或
