Forest Ecosystem

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FOREST
ECOSYSTEM

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Forest Ecosystem

Table of Contents
(Outline)
I. Introduction
II. The Structure of Forests
III. Kinds of Forest
IV. The Distribution of the Forests
V. Forests Succession
VI. The History of Forests
VII. Deforestation
VIII. Conclusion
IX. Endnotes
X. Bibliography

Forest Ecosystem

I. Introduction
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending on various cultural definitions, what is considered a forest may vary significantly in size and have different classifications according to how and what of the forest is composed? These plant communities cover approximately 9.4 percent of the Earth's surface (or 30 percent of total land area), though they once covered much more (about 50 percent of total land area), in many different regions and function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the biosphere. Although forests are classified primarily by trees, the concept of a forest ecosystem includes additional species (such as smaller plants, fungi, bacteria, and animals) as well as physical and chemical processes such as energy flow and nutrient cycling. A typical forest is composed of the over story (canopy or upper tree layer) and the understory. The understory is further subdivided into the shrub layer, herb layer, and also the moss layer and soil microbes. In some complex forests, there is also a well-defined lower tree layer. Forests are central to all human life because they provide a diverse range of resources: they store carbon, aid in regulating the planetary climate, purify water and mitigate natural hazards such as floods. Forests also contain roughly 90 percent of the world's terrestrial biodiversity. Forests are habitats in which the trees are the dominant form of vegetation. They occur in many regions and climates around the globe—the tropical rainforests of the Amazon basin, the temperate forests of eastern North America, and the boreal forests of northern Europe are just a few examples. The species composition of a forest is often unique to that forest, with some forests consisting of many hundreds of species of trees while others consist of just a handful of species. Forests are constantly changing and progress through a series of succession stages during which species composition changes within the forest. Thus, making general statements about forest habitats can be difficult. Yet despite the variability of our planet's forests, there are some basic structural characteristics that many forests share—characteristics that can help us to better understand both forests and the animals and wildlife that inhabit them. The forest floor is often blanketed with decaying leaves, twigs, fallen trees, animal scat, moss, and other detritus. The forest floor is where recycling occurs, fungi, insects, bacteria, and earthworms are among the many organisms that break down waste materials and ready them for reuse and recycling throughout the forest system. The herb layer of the forest is dominated by herbaceous (or soft-stemmed) plants such as grasses, ferns, wildflowers, and other ground cover. Vegetation in the herb layer often gets little light and in forests with thick canopies, shade tolerant species are predominant in the herb layer. The understory of a forest consists of immature trees and small trees that are shorter than the main canopy level of the tree. Understory trees provide shelter for a wide range of animals. When gaps form in the canopy, often times understory trees take advantage of the opening and grow to fill in the canopy. The canopy is the layer where the crowns of most of the forest's trees meet and form a thick layer. Emergent are trees whose...
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