- 千歲Lv 51 十年前最愛解答
熱帶樹木主要出現於熱帶雨林, There are several common characteristics of tropical rainforest trees. Tropical rainforest species frequently possess one or more of the following attributes not commonly seen in trees of higher latitudes or trees in drier condirions on the same latitude.
Many tree species have broad, woody flanges (buttresses) at the base of the trunk. Originally believed to help support the tree, now it is believed that the buttresses channel stem flow and its dissolved nutrients to the roots.
Large leaves are common among trees and shrubs of the understory and forest floor layers. Young individuals of trees destined for the canopy and emergent layers may also have large leaves. When they reach the canopy new leaves will be smaller. The large leaf surface helps intercept light in the sun-dappled lower strata of the forest and are made possible because the lower layers are largely protected from winds which damage large leaves in the canopy. Canopy leaves are usually smaller than found in understory plants or are divided to reduce wind damage. The leaves of rainforest understorey trees also often have drip tips which facilitate drainage of precipitation off the leaf to promote transpiration and inhibit the growth of microbes and bryphytes which would damage or smother the leaf .
Trees are often well connected in the canopy layer especially by the growth of woody climbers known as lianas or by plants with epiphytic adaptations, allowing them to grow on top of existing trees in the competition for sunlight.
Other characteristics that are more frequent in tropical rainforest tree species than in temperate forests or drier tropical regions include:
Exceptionally thin bark, often only 1-2 mm thick. It is usually very smooth, although sometimes covered with spines or thorns.
Cauliflory, the development of flowers (and hence fruits) directly from the trunk, rather than at the tips of branches.
Large fleshy fruits attract birds, mammals, and even fish as dispersal agents.
2006-12-09 19:05:21 補充：