Elevation levels Altitudinal zonation

elevation models of zonation complicated factors discussed above , relative altitudes each zone begins , ends not tied specific altitude. possible split altitudinal gradient 5 main zones used ecologists under varying names. in cases these level follow each other decrease in altitude, called vegetation inversion.

altitudinal zonation of grand teton in rocky mountains (note change in vegetation altitude increases)



nival level (glaciers): covered in snow throughout of year. vegetation extremely limited few species thrive on silica soils.
alpine level: zone stretches between tree line , snowline. zone further broken down sub-nival , treeless alpine (in tropics-tierra fria; low-alpine)

sub-nival: highest zone vegetation typically exists. area shaped frequent frosts restrict extensive plant colonization. vegetation patchy , restricted favorable locations protected heavy winds characterize area. of region patchy grassland, sedges , rush heaths typical of arctic zones . snow found in region part of year.
treeless alpine (low-alpine): characterized closed carpet of vegetation includes alpine meadows, shrubs , sporadic dwarfed trees. because of complete cover of vegetation, frost has less of effect on region, due consistent freezing temperatures tree growth severely limited.


montane level: extends mid-altitude forests tree line. exact level of tree line varies local climate, typically tree line found mean monthly soil temperatures never exceed 10.0 degrees c , mean annual soil temperatures around 6.7 degrees c. in tropics, region typified montane rain forest (above 3,000 ft) while @ higher latitudes coniferous forests dominate.
lowland layer: lowest section of mountains varies distinctly across climates , referred wide range of names depending on surrounding landscape. colline zones found in tropical regions , encinal zones , desert grasslands found in desert regions.

colline (tropics): characterized deciduous forests when in oceanic or moderately continental areas, , characterized grassland in more continental regions. extends sea level 3,000 feet (roughly 900 m). vegetation abundant , dense. zone typical base layer of tropical regions.
encinal (deserts): characterized open evergreen oak forests , common in desert regions. evaporation , soil moisture control limitation of encinal environments can thrive. desert grasslands lie below encinal zones. commonly found in southwestern united states.
desert grassland: characterized varying densities of low lying vegetation, grasslands zones cannot support trees due extreme aridity. desert regions may support trees @ base of mountains however, , distinct grasslands zones not form in these areas.

for detailed breakdowns of characteristics of altitudinal zones found on different mountains, see list of life zones region.