Clear-cutting: Method of timber harvesting in which all trees in a forested area
are removed in a single cutting leaving bare soil exposed.
Deforestation: Removal of trees from a forested area without adequate
replanting.
Endangered species: A wild species with so few individual survivors that the
species could soon become extinct in all or most of its natural regions.
Erosion: Process of group of processes by which loose or consolidated earth
materials are dissolved, loosened, or worn away and removed from one place
and deposited in another.
Extinction: Complete disappearance of a species from the earth. This happens
when a species cannot adapt and successfully reproduce under new
environmental conditions or when it evolves into one or more new species.
Greenhouse Gases: Gases in the earth’s lower atmosphere (troposphere) that
cause the greenhouse effect. Examples are carbon dioxide, chlorofluorocarbons,
ozone, methane, water vapor, and nitrous oxide.
Habitat: Place or type of place where an organism or population of organisms
lives.
Keystone species: A species whose presence and role within an ecosystem has a
disproportionate effect on other organisms within the system. A keystone species
is often a dominant predator whose removal allows a prey population to explode
and often decreases overall diversity. Other kinds of keystone species are those,
such as coral or beavers that significantly alter the habitat around them and thus
affect large numbers of other organisms.
Logging: the process, work, or business of cutting down trees and transporting
the logs to sawmills.
Monoculture: cultivation of a single crop, usually on a large area of land.
Pest: Unwanted organism that directly or indirectly interferes with human
activities.
Plantation agriculture: Growing specialized crops such as bananas, coffee, and
cacao in tropical developing countries, primarily for sale to developed countries.
Population: Group of individual organisms of the same species living in a
particular area.
Rainforest: a tropical forest, usually of tall, densely growing, broad-leaved
evergreen trees in an area of high annual rainfall.
Rainforest Canopy: the cover formed by the leafy upper branches of the trees in a
forest.
Renewable Resource: Resource that can be replenished rapidly (hours to several
decades) through natural processes. Examples are treed in forests, grasses in
grasslands, wild animals, fresh surface water in lakes and streams, most
groundwater, fresh air, and fertile soil. If such a resource is used faster than it is
replenished, it can be depleted and converted to a nonrenewable resource.
Tolerance: Minimum and maximum limits for physical conditions (such as
temperature) and concentrations of chemical substances beyond which no
members of a population can survive.