Life Zones of Glacier National Park

LIFE ZONES OF GLACIER NATIONAL PARK

Harold E. Bailey

In driving over the Going-to-the-Sun Highway everyone observes that there are changes in the kind of plants and animals found at lower elevations as compared to those at higher elevations. Very few plants grow in the valleys that are found on the mountain tops. For example, the dense cedar-hemlock-larch forests around Lake McDonald stand out in striking contrast to the sparse alpine fir growth found at Logan Pass. Animal and plant life not only changes with the different altitudes but it also changes with differences in latitude. Plants and animals of the tropics differ from those of the temperate or arctic regions. It has been found that every 1000 feet rise in elevation is equivalent to traveling 300 miles north from the equator. Biologists have tried to correlate such facts by advancing the life zone concept. Roughly speaking, the vegetation is divided into belts or zones depending upon the temperature and moisture.

A journey along the Pacific coast of North America from the state of Sonora in Mexico to the Arctic Circle is equivalent to climbing from the base to the top of a high snow-capped peak in Sonora. In making either trip several life zones are traversed. The first or lowest zone, with the climate typical of the state of Sonora, is called the Sonoran Zone. In it are found desert and semi-desert types of plants. Needless to say, such a zone does not occur in the park.

Each of the other zones does occur in the park. The lowest of these, with a temperate climate resembling that found in the Great Plains area and that covered by the ponderosa pine forests of the Pacific Coast, is called the Transition Zone, since it is Transitional between the hot semi-arid regions and the cool, moist, timbered regions of Canada. This latter zone is known as the Canadian Zone. The Hudsonian Zone, above the Canadian Zone, is typified by stunted alpine forest growth as found at Logan Pass or in the Hudson Bay area in Canada. The Arctic-Alpine-Zone has no trees and plant growth found there is comparable to that found in the Arctic regions. Everything above timberline is considered in this Life Zone.

In traversing the Going-to-the-Sun Highway in Glacier National Park one passes through four life zones. The Transition Zone is rare within the park. It is represented on the east side of the park by the Plains type of vegetation which comes into the lower areas and on the west side of the park by small groves of ponderosa pine along the North Fork of the Flathead River.

The main forest belt is chiefly in the Canadian Zone with tree species including lodgepole pine, Douglas fir, spruce, and alpine fir. Western larch, western red cedar, western hemlock, and western white pine occur also on the west side of the park while limber pine occurs on the east side. Animals found commonly in this zone are numerous and many range up into the Hudsonian Zone. Among the more conspicuous game animals are bear, elk, deer, and moose. Red-Osier dogwood, red and black twinberry, thimbleberry, wild hollyhock, cow parsnip, geranium, purple asters, are some of the common showy plants in this forest belt.

The Hudsonian Zone may be considered to be at and just below timber line in the upper part of the forest belt where the trees become small and stunted and the forests much more open. Tree species most commonly found in this zone are the alpine fir and the whitebark pine. Other species such as the limber pine, the lodgepole pine, and the Englemann spruce may also occur here. The alpine larch, comparatively rare in the park, is restricted to this zone. The ptarmigan, whistling marmot, and grizzly bear are common animal species.

The Arctic Alpine Zone is marked by wide alpine meadows or rocky open places where there are no trees. Plant species such as are found along the trail to Hidden Lake Pass and in the Hanging Gardens are typical of the Arctic Alpine Zone. Some of these include red mountain heather, mountain sorrel, alpine cottonweed, alpine meadow rush, alpine cinquefoil, elephanthead, lousewort, alpine arnica, yellow and red paintbrush, rock cress, several saxifrages, pentstemon, etc.

Most park visitors would be interested in the changes in the life zones if these were pointed out in a drive over the Going-to-the-Sun Highway.

Hibernating Mosquitoes - Large mosquitoes with spotted wings - as big as eagles, according to many tourists - are found at the higher altitudes. These mosquitoes are the first observed on the wing in early spring and are often referred to as snow mosquitoes. They hibernate all winter as adults under logs and in sheltered spots, and may be seen flying on the first warm day of spring. They persist all year. One night with the temperature about 36 degrees Fahrenheit as we sat around the camp fire at Granite Park Chalet, I picked one from my neighbor's person. Two Russian scientists, Doctors N. Kadletz and L. Kusmina, assert that these mosquitoes like bears store up fat in summer and persist on it while dozing thru the winter. 'Tis a pity that there resemblance ceases.

- G. Allen Mail.