Temperate regions lie to the north and south of the tropics (23.5o latitude). Deciduous temperate trees shed their leaves each winter. Nearer the poles “boreal" forests of conifers cover the largest area of any forest type in the world. Conifers also dominate temperate forests at higher altitudes and in places where soils are poor.
Temperate forests have been cleared for agriculture and felled for timber for thousands of years. In the late 20th century this trend slowed as populations in temperate regions stabilized and resources other than timber were used for fuel and building materials. In the 1990s the area of temperate forest cover worldwide rose. However, the ecological quality of many forests has continued to decline as plantations replaced “old growth” forests and the frequency of fires has risen. Fires started by people consume an average of one percent of the existing Mediterranean forest every year.
Inappropriate planting of trees to act as “carbon sinks”, a measure to counteract global warming, can actually reduce biodiversity. Most plantations are comprised of a few or even a single tree species such as eucalyptus and pine that may be alien to that habitat. Plantations do, however, make an indirect contribution to conservation by relieving the need to log “old growth” forests. Some plantations are now certified under schemes that demonstrate they are sustainably managed.
When forests become fragmented the plants and animals in each forest fragment can be isolated from adjacent forests and local extinction may result. It also becomes more difficult for species to migrate in response to climate change.
Pollution has also damaged temperate forests. The burning of fossil fuels releases sulfur and nitrogen into the atmosphere. Transported by the wind this can fall to earth as dry deposits or combine with water to form “acid rain”. Polluting gases are also converted by sunlight into ozone, which interferes with the biological functioning of plants. Forests hundreds of miles from industrial centers are affected, in particular those in the northeast of North America, in East Asia and in northeastern Europe and Scandinavia.
Have a great animal video we should know about? Want to contribute content to Jeff Corwin Connect Email us here