If the mountain is high enough, the climate of
the crest may be too severe for forests. In such
places there will be a more or less marked
timberline, above which is the alpine zone.
The alpine zone has many extreme climatic
conditions found in arctic climates, and because
the atmosphere is thinner at high altitude, the
light intensity is much greater. Most alpine plants
grow near the ground where they are protected
from the wind. Very few animals inhabit the
alpine zone year-round. Those that do, such as
the pika, tend to be small because of the scarcity
of food. Large mammals, such as the mountain
goat and the guanaco, rely on well-insulated
coats for protection.
Above the tree line and the alpine zone is the
climatic snow line, the boundary of the area
covered by rock and permanent snow and ice
(Fig. 9.5).
Other climatic elements reinforce the effects
of temperature on vertical differentiation.
Table 9.1 List of the types of elevational spectra
Name of division
Elevational spectra
110 Icecap
Polar desert
120 Tundra
Tundra—polar desert
130 Subarctic
Open woodland—tundra; taiga—tundra
210 Warm continental
Mixed forest—coniferous forest—tundra
220 Hot continental
Deciduous or mixed forest—coniferous forest—meadow
230 Subtropical
Mixed forest—meadow
240 Marine
Deciduous or mixed forest—coniferous forest—meadow
250 Prairie
Forest—steppe—coniferous forest—meadow
260 Mediterranean
Mediterranean woodland or shrub—mixed or coniferous forest—steppe or meadow
310 Tropical/subtropical
steppe
Steppe or semi-desert—mixed or coniferous forest—alpine meadow or steppe
320 Tropical/subtropical
Semi-desert—shrub—open woodland—desert steppe or alpine meadow
desert
330 Temperate steppe
Steppe—coniferous forest—tundra; steppe—mixed forest—meadow
340 Temperate desert
Semi-desert woodland—meadow
410 Tropical savanna
Open woodland—deciduous forest—coniferous forest—steppe or meadow
420 Tropical rainforest
Evergreen forest—meadow or paramos
Fig 9.3 Montane forest in the Kenya uplands. The tree
limb is completely covered with epiphytes. Photograph by
Carl Akeley. Image #211362, American Museum of
Natural History, Library
Fig 9.4 Open montane forest of ponderosa pine in
Coconino National Forest, near Happy Jack, Arizona,
elevation 2,284 m. Photograph by Robert G. Bailey
9.1 M Mountains with Elevational Zonation
91
the crest may be too severe for forests. In such
places there will be a more or less marked
timberline, above which is the alpine zone.
The alpine zone has many extreme climatic
conditions found in arctic climates, and because
the atmosphere is thinner at high altitude, the
light intensity is much greater. Most alpine plants
grow near the ground where they are protected
from the wind. Very few animals inhabit the
alpine zone year-round. Those that do, such as
the pika, tend to be small because of the scarcity
of food. Large mammals, such as the mountain
goat and the guanaco, rely on well-insulated
coats for protection.
Above the tree line and the alpine zone is the
climatic snow line, the boundary of the area
covered by rock and permanent snow and ice
(Fig. 9.5).
Other climatic elements reinforce the effects
of temperature on vertical differentiation.
Table 9.1 List of the types of elevational spectra
Name of division
Elevational spectra
110 Icecap
Polar desert
120 Tundra
Tundra—polar desert
130 Subarctic
Open woodland—tundra; taiga—tundra
210 Warm continental
Mixed forest—coniferous forest—tundra
220 Hot continental
Deciduous or mixed forest—coniferous forest—meadow
230 Subtropical
Mixed forest—meadow
240 Marine
Deciduous or mixed forest—coniferous forest—meadow
250 Prairie
Forest—steppe—coniferous forest—meadow
260 Mediterranean
Mediterranean woodland or shrub—mixed or coniferous forest—steppe or meadow
310 Tropical/subtropical
steppe
Steppe or semi-desert—mixed or coniferous forest—alpine meadow or steppe
320 Tropical/subtropical
Semi-desert—shrub—open woodland—desert steppe or alpine meadow
desert
330 Temperate steppe
Steppe—coniferous forest—tundra; steppe—mixed forest—meadow
340 Temperate desert
Semi-desert woodland—meadow
410 Tropical savanna
Open woodland—deciduous forest—coniferous forest—steppe or meadow
420 Tropical rainforest
Evergreen forest—meadow or paramos
Fig 9.3 Montane forest in the Kenya uplands. The tree
limb is completely covered with epiphytes. Photograph by
Carl Akeley. Image #211362, American Museum of
Natural History, Library
Fig 9.4 Open montane forest of ponderosa pine in
Coconino National Forest, near Happy Jack, Arizona,
elevation 2,284 m. Photograph by Robert G. Bailey
9.1 M Mountains with Elevational Zonation
91