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Roles of Forests

Forest as a Habitat:

Although trees are the largest, most productive organisms in forests, the forest ecosystem is much more than a population of trees growing on the land. Forests also provide habitat for a host of other species of plants, along with numerous animals and microorganisms. Most of these associated species cannot live anywhere else; they have an absolute requirement of forested habitat. Often that need is very specific, as when a bird species needs a particular type of forest, in terms of tree species, age, and other conditions.

For example, Kirtland’s warbler (Dendroica kirtlandii) is an endangered species of bird that only nests in stands of jack pine (Pinus banksiana) of a particular age and density in northern Michigan. This songbird does not breed in any other type of forest, including younger or older stands of jack pine. Similarly, the endangered spotted owl (Strix occidentalis) only occurs in certain types of old-growth conifer forests in western North America. These same old-growth forests also sustain other species that cannot exist in younger stands, for example, certain species of lichens, mosses, and liverworts.

Usually, however, the many species occurring in forests have a broader ecological tolerance, and they may in fact require a mosaic of different habitat types. In eastern North America, for example, white-tailed deer (Odocoileus virginianus) do well in a mixture of habitats. They require access to relatively young, successional stands with abundant and nutritious food for this species, along with refuge habitat of mature forest with some conifer-dominated areas that have shallower snow depth in winter. Similarly, ruffled grouse (Bonasa umbellus) does best on a landscape that has a checkerboard of stands of various age, including mature forest dominated by trembling aspen (Populus tremuloides) with a few conifers mixed in.


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Forest as Resource:

Timber: Wood is by far the most important product harvested from forests. The wood is commonly manufactured into paper, lumber, plywood, and other products. In addition, in most of the forested regions of the less-developed world firewood is the most important source of energy used for cooking and other purposes.


Non Timber Forest Products (NTFP): Nontimber forest products (NTFPs) broadly include all non-industrial timber vegetation in forests and agroforestry environments with, or potentially with, commercial value.  Other terms synonymous with nontimber forest product include special forest product, non-wood forest product, minor forest product, alternative forest product and secondary forest product.  Other terms synonymous with harvesting include wildcrafting, gathering, collecting and foraging.

Some commonly collected nontimber forest products (NTFPs) in the U.S. are wild mushrooms, berries, ferns, tree boughs, cones, moss, maple syrup, honey, and medicinal products such as cascara bark and ginseng. NTFP is not a biological or ecological category; it is a political and economic category that serves to highlight forest resources that are by-passed or overlooked in forest management as a viable income source.



Forest and Recreation:

By providing a host of outdoor recreational opportunities, forests encourage people to live healthy, active lifestyles. They also improve mental and spiritual well-being through bonding with others and connecting with nature.

Recreational activities in forests nurture people’s appreciation for the essential role that forests play in preserving the health of our planet and the well-being of its inhabitants.

Michelle Obama’s Let’s Move initiative encourages the nation’s youth to lead more active lifestyles from a young age. Offering kids ideas on how to have fun while being active will help to lessen their chances of health-related issues in the future.

Investing in forests for recreation opportunities, such as tourism, hiking, and camping, also provides a boost to the local economy, and a sense of pride in the surrounding communities.


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Role of Forests in Climate Change:

Forests have four major roles in climate change: they currently contribute about one-sixth of global carbon emissions when cleared, overused or degraded; they react sensitively to a changing climate; when managed sustainably, they produce woodfuels as a benign alternative to fossil fuels; and finally, they have the potential to absorb about one-tenth of global carbon emissions projected for the first half of this century into their biomass, soils and products and store them – in principle in perpetuity.


Forests influence climate change largely by affecting the amount of carbon dioxide in the atmosphere. When forests grow, carbon is removed from the atmosphere and absorbed in wood, leaves and soil. Because forests (and oceans) can absorb and store carbon over an extended period of time, they are considered “carbon sinks”. This carbon remains stored in the forest ecosystem, but can be released into the atmosphere when forests are burned. Quantifying the substantial roles of forests in absorbing, storing, and releasing carbon is key to understanding the global carbon cycle and hence climate change.


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More Ecological Functions of Forests:

The forest changes lifeless rock into a living ecosystem. Over thousands of years the plants and animals of the forest establish themselves and build a living cover of green. The forest grew slowly. A newly exposed area of land will first be colonized by a few plants which were very strong and could live on bare rock. Slowly other plants and animals followed. The forest which covers the land today may be thousands of years old. You can cut down some trees and not hurt it at all. But if you cut down too many trees all at once, you can destroy it.

The forest makes the soil. The soil on the land is the old broken-down rock mixed with the dead plants of the forest and the many small animals and bacteria and plants which live in the soil. Forests made most of the soil on the planet. When garden soil becomes poor the forest grows over the old garden and makes the soil good again.

The forest protects the soil. It holds the soil with its roots. If the trees are cut down and no gardens are planted the soil gets hard and dry and no good for gardens. If heavy rains come and there are no trees, the soil gets muddy and washes away, polluting streams, rivers and the sea. Then the soil is gone and gardens will not grow on the hard rock.

The forest shelters the gardens. When strong winds and heavy rains come the trees protect the gardens. Strong winds can hurt crops and dry out the soil. Near the coast, salt spray can poison the soil or harm the crops without the shelter of trees. The forest can also protect homes and villages from strong winds.

The forest holds water. The trees and the soil they make are full of water and they store this water for times of no rain. The forest controls the flow of water over the land. When heavy rains come the trees help trap the water in the soil. They hold water in their branches, trunks, roots and leaves. When the land is dry the water from the forest keeps the land green. Without the trees of the forest the land can quickly become dry and the crops may die.

The forest makes clouds and rain. When the wind blows over the land it moves through the trees and the trees put water into the wind. When the wind goes through the trees, the trees also put excess heat from the sun into the wind. The heated, wet air then lifts up because hot air rises. When the hot, wet air hits the cooler wind above the land, it becomes clouds. If you cut down the trees there may be less rain and the land may dry up; people will then not have enough water to drink or wash in and the crops will die.

The forest prevents fires. When the forest is dead the land becomes dry and can quickly catch on fire and burn away all the life.


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