Emerald Robinson: Hi, I'm Emerald Robinson, and in this What is video, we'll look at the tree communities we commonly call Forests. A forest is any area where many trees grow closely together. Forests cover about 30% of the earth's land, 9% of its total surface. Also called woods, what specifically defines a forest varies widely between different cultures and communities, but there are some qualities that all forests share.
Ecologists who study forests divide them into layers. The top layer, or overstory, consists of tree tops, or canopy. The lower layer, or understory, is everything below the canopy, shorter plants and bushes, fungi and mosses, even the forest floor. Forests also include non-living parts, like air, water, nutrients, and sunlight. Together these make a forest ecosystem.
There are three main types of forests.
Tropical forests are found near the equator. Tropical forests experience no change in season, and get about 12 hours of sunlight daily. While most of us think of tropical rainforests, there are also evergreen and deciduous tropical forests.
Boreal forests, or taiga, are the cold forests of North America, Europe and Asia, found between the latitudes of 50 and 60 degrees north. Boreal forests generally have evergreen and coniferous trees, and experience a short summer and a long winter every year.
Temperate forests are the forests found north of the tropics but south of the taiga. Temperate forests generally have broadleaf and coniferous trees and have four fairly equal seasons each year, with an even distribution of precipitation throughout those seasons.
Healthy forests are vital for life on earth. Trees' leaves release oxygen and remove pollution from the air, while their roots help control soil erosion. Forests also provide many natural resources such as wood, fruit, and rubber.
Forests contain about 90 percent of our planet's biodiversity. This biodiversity is threatened by destruction of earth's forests, or deforestation. Forest conservation is necessary so we can continue to enjoy their benefits.