Over the years, and especially since the Second World War, the　realm of landscape architecture has been diversified and its　activities classified in response to the needs of a changing world.　There now appear to be three clearly definable related stages. First　there is landscape planning and assessment. This has a strong　ecological and natural science base and is concerned with the　systematic evaluation of large areas of land in terms of the land's　suitability or capability for any likely future use. The process　usually involves a team of specialists. It may result in a land use　plan or policy, affecting, for example, the distribution and type of　development or land use, the alignment of highways, the location of　industrial plant, the conservation of water, soil, and amenity　values, and the use of countryside for recreation. The study area　usually coincides with a natural physiographic region such as the　watershed of a major river or some other logical unit of land;unfortunately these seldom coincide with the legal jurisdiction of　county and state boundaries. The planning function may at times be　less comprehensive and concentrate on the impact of major proposals　on the environment or the identification of land suitable for one　major use such as recreation.

　　The second stage is site planning. This represents the more　conventional kind of landscape architecture and within this realm　lies landscape design. Site planning is the process in which the　assessment of the site and the requirements of the program for the　use of the site are brought together in creative synthesis. Elements　and facilities are located on the land in functional relationships　and in a manner fully responsive to the characteristics of the site　and its region.

　　Finally, there is detailed landscape design. This the selection　of components, materials, and plants and their combination as　solutions to limited and well-defined problems; paving, steps,fountains, and so forth. This is the process through which specific　quality is given to the diagrammatic spaces and areas of the site　plan.

　　重点单词：

realm : n. 王国,领土,领域

landscape : n. 风景,山水,风景画;vi. 进行造园工程;vt. 使自然美化

diversified : a. 多变化的,各种的

activity : n. 活动,动作,活力

classified : a. 分类的,类别的,被指定为机密的

response : n. 反应,回答,响应

definable : a. 可解说的,可下定义的,可解释的

assessment : n. 评估,估定,评定的款额

ecological : a. 生态学的,社会生态学的

systematic : a. 有系统的,分类的,体系的

evaluation : n. 评估,估价,求值

capability : n. 能力,性能,容量