An Introduction to Mountains - Mountain Geography: Physical and Human Dimensions - page 6

able climatic changes with altitude (Thompson 1964; Körner 2003; Barry 2008). The
major advantage of this approach is that it recognizes ecology as well as topography.
Clearly, one of the most distinctive characteristics of mountains, in addition to high re-
lief and steepness of slope, is great environmental contrast within a relatively short dis-
tance (this volume, Chapters 7 and 11).
German-speaking peoples differentiate between the Hochgebirge (high mountains)
and Mittelgebirge (medium mountains). The Harz Mountains and the Black Forest are
Mittelgebirge, whereas the Alps are the classic example of Hochgebirge (Troll 1972: 2).
French has the comparable terms hautes montagnes and moyennes montagnes; and in
English we speak of the High Sierra or the High Cascades as opposed to the Sierra or
the Cascades. The coastal ranges of the western United States are low mountains, and
the Rockies are high mountains, but what distinguishes high mountains from low? Elev-
ation alone is not sufficient: Compare the high plateaus of Tibet with the modest elev-
ations of western Spitsbergen. High relief is not reliable, either: the California coastal
ranges are on the whole probably more rugged than are most parts of the Rockies.
Climate is the best determinant of where the alpine zone begins. For this reason, high
mountain landscapes occur at different altitudes under different environmental condi-
tions. In Java, the volcano Pangerango, which rises from sea level to 3,000 m (10,000
ft), is covered with tropical rainforest to its summit. “It is a high mountain without a
high mountain landscape” (Troll 1972: 2).
The word “alpine” is European in origin, dating to pre-Roman times, with its roots
in “alp” or “allo” meaning “mountain” (Körner 2003; Löve 1970). In Europe, New Zea-
land, and Japan, the term is commonly applied to whole mountain ranges that can in-
clude valleys, forests, and pastures. In biogeographical terms, however, the alpine life
zone is confined to vegetation above the natural high-altitude forest or timberline. This
is generally lowest in the polar regions, where “alpine” and “arctic” life zones with very
similar geomorphological and ecological characteristics merge, and rises in elevation
toward the equator. It is not a simple, straight-line relationship, however. The highest
elevations at which trees grow occur at about 30° latitude in the arid zones of the Andes
and Himalayas, rather than in the humid tropics (Körner 2003). Timberline also tends
to rise from coastal areas toward the continental interiors. Thus, on Mount Washing-
ton in New Hampshire, the alpine zone begins at 1,500 m (5,000 ft); in the Rockies of
Wyoming it occurs at over 3,000 m (10,000 ft); and in the Oregon Cascades, it drops
again to 1,800 m (6,000 ft) (Daubenmire 1954: 121). Although the upper timberline is
probably the major criterion for determining where the high mountain environment be-
gins, it should not be the sole determinant. Because different tree species have differ-
ent climatic requirements, contrasting abilities and potentials are involved in different
regions. Geological or other natural factors may result in abnormally low timberlines.
In addition, many timberlines have been greatly affected by human interference, espe-
cially through the agency of fire, cutting, and grazing, so they are not easily compared
(Hedberg 1972, 1995; Braun et al. 2002; Broil and Keplin 2005).
TABLE I.I
Global Typology of Mountain Classes