Study of the Alaska Tundra with Reference to its Reactions to Reindeer and other Grazing Page: 15
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STUDY OF THE ALASKA TUNDRA
was clipped so as to remove about three-fourths of the above-
ground growth. Before the cutting, the area had a complete
ground cover composed of about 60 percent lichens, 38 percent
browse, and 2 percent grasses. The cutting was done in the
spring while the ground was frozen. An examination made after
the ground had thawed disclosed a weak lichen cover approxi-
mately half an inch high remaining.
After 9 years the vegetation on this area had a density of 0.95
and was composed of 25 percent grasses, 35 percent lichens, 25
percent browse, 10 percent mosses, and 5 percent weeds. The
greater part of the lichen cover died during the year after the
cutting but new growth was soon in evidence. The stand was
opened, however, and this allowed the establishment of grasses
and weeds. In 5 years the ground cover had a density of 0.95.
In 9 years the lichens had attained a height of 1 inches but
were only slightly more than half as abundant as formerly. This
would indicate that lichens are greatly affected by cropping, that
they are very slow to recover, and are easily killed. Grazing
tends to open the stand in this type and this permits the increase
of grasses and weeds. The browse species were reduced by the
cutting but they recovered more rapidly than did the lichens.
Denuded quadrat.-A similar quadrat, having a 1.0 density of
cover composed of 75 percent lichens, 15 percent browse, and 10
percent grasses, was completely denuded in order to observe the
recovery of the lichens. In 5 years the area was largely covered
with grasses and browse to a density of 0.8. Lichens had come in
rapidly but were of short growth. Nine years after establish-
ment of the quadrat the vegetation had attained a .0.9 density
and was estimated to be composed of 35 percent grasses, 25 per-
cent browse, 30 percent lichens, 5 percent weeds, and 5 percent
mosses. The lichens averaged about 1 inch in height.
In this instance the grasses were most aggressive in revegetat-
ing the area after the lichens were removed. Browse species also
were stimulated by the opening up of the stand. Lichens were
slow to reestablish themselves but were doing so, gradually. The
increased growth and spread of lichens was relentlessly crowding
out and replacing the grasses, and eventually, during the course
of years, would reclaim the area. The browse species tend to be
more stable, but evidence indicates that finally they, too, give
way to the lichens.
Picked quadrat.-A third quadrat in this group was originally
covered with vegetation having a 1.0 density, and composed of
70 percent lichens, 25 percent grasses, and 5 percent browse. To
study the effect of pawing and close winter cropping by reindeer
on lichen growth, the lichens on this quadrat were picked by
hand while the ground was frozen. The air-dry weight of these
lichens averaged with that of the lichens removed from the de-
nuded quadrat mentioned above indicated a forage production
of 10,117 pounds to an acre. Examination of the area after the
ground had thawed showed that no lichens were left. Five years
after establishment the quadrat had a complete cover of vege-
tation estimated to be composed of 50 percent grasses, 25 percent
649869*-46-315
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Palmer, Lawrence J. & Rouse, Charles H. Study of the Alaska Tundra with Reference to its Reactions to Reindeer and other Grazing, report, 1945; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc100536/m1/20/?rotate=270: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.