141. Late-lying snow reduces the effective growing season to the point where seedlings cannot establish themselves.
142. Wind velocity also increases with altitude and may cause serious stress for trees, as is made evident by the deformed shapes at high altitudes.
143. Some scientists have proposed that the presence of increasing levels of ultraviolet light with elevation may play a role, while browsing and grazing animals like the ibex may be another contributing factor.
144. Immediately adjacent to the timberline, the tundra consists of a fairly complete cover of low-lying shrubs, herbs, and grasses, while higher up the number and diversity of species decrease until there is much bare ground with occasional mosses and lichens and some prostrate cushion plants.
145. At this great height, rocks, warmed by the sun, melt small snowdrifts
146. This enables them to avoid the worst rigors of high winds and permits them to make use of the higher temperatures immediately adjacent to the ground surface.
147. The low growth form can also permit the plants to take advantage of the insulation provided by a winter snow cover.
148. The client who pays for the building and defines its function is an important member of the architectural team.
149. The mediocre design of many contemporary buildings can be traced to both clients and architects.
150. In order for the structure to achieve the size and strength necessary to meet its purpose, architecture employs methods of support that, because they are based on physical laws, have changed little since people first discovered them-even while building materials have changed dramatically.
