 |
Life Zones and Altitudinal Zonation |
 |
|---|
|
Life Zones and Altitudinal Zonation |
|
|---|
The affects of climatic variables, especially temperature and precipitation, on the distribution of plant life has long been recognized. Alexander van Humboldt first wrote in 1807 of the relationship between climate and vegetation and for his pioneering work has been called the "Father of Plant Geography." And the familiar Koeppen climate classification system (1930) was actually based major natural vegetation patterns.
When you climb a high mountain, you quickly become aware of the impact of cooling temperature and higher precipitation on local vegetation types. In 1889, C. Hart Merriam studied the relationship between mean annual temperature and the distribution of flora and fauna in the western United States. He recognized that similar zones or belts of vegetation occurred with both increasing latitude and increasing elevation. He called these belts Life Zones.
Altitudinal zonation of vegetation is obvious on high peaks around the world. And while there may be similarity between the structure of the vegetation in these various elevation belts with that in latitudinal belts, there are usually major differences in the species present in each. In other words, the elevational plant communities are not exact replicas of the latitudinal plant associations. Mountain climates vary in critical ways from regional climate types. Consider the differences in annual and diurnal patterns of daylength, angle of incoming solar radiation, intensity of direct radiation, and precipitation on a towering mountain peak near the equator, for example, and on the Arctic coast of Alaska.
Various altitudinal zonation classification schemes have been developed to reflect site-specific conditions of climate and vegetation in mountain areas around the world. From this page you can access diagrams, photos, and text about several commonly used altitudinal zonation classifications:
Virtual field trips concerned with altitudinal zonation in: