EEINDEER GRAZING INVESTIGATIONS IN ALASKA 19 
As to general conditions, the climate is considered more moderate in 
the Kuskokwim River valley to the south, and in the Kobuk River 
valley above the Arctic Circle, than in the regions lying between. 
Much lower winter temperatures prevail in the far interior areas 
than in the coast belt, but the higher winter temperatures of the 
coast region are offset by the greater humidity and prevalence of 
wind. 
SEASONAL VARIATIONS 
Seasonal variations also have an imporant bearing on reindeer 
grazing. The summer forage crop may be greatly decreased by a 
backward season or increased by favorable conditions. Thus there 
are poor feeding seasons and there are good ones, each in turn being 
clearly reflected in the condition of the grazing animal. Variation 
in the advances of the spring season is a problem at fawning time. 
Under very late conditions greater care must be taken for the pro- 
tection of the newborn fawns, which often come very early in Alaska. 
Although reindeer fawns are remarkably hardy and capable of with- 
standing the ordinary vicissitudes of climate, yet extreme conditions 
sometimes result in heavy losses unless precautions are taken. 
Perhaps most important of all is the effect that the varied seasons 
have on the fly pest and consequently on the reindeer. During a 
prevailing cloudy and rainy season, as experienced in 1922, the 
number of warble flies is greatly reduced and in some sections they 
may almost disappear. Under such conditions the reindeer are able 
to graze unmolested. 
SOIL CONDITIONS IN ALASKA 
Soil conditions are an important consideration in the selection of 
a range, chiefly as influencing plant growth, especially lichens. 
Within the three main ground types — dry tundra, wet tundra, and 
rocky areas — are various kinds of soils, the one predominating on 
tundra areas varying between a black sandy loam and a sandy clay 
loam over a blue cla}^ subsoil. The tundra soils are rich in humus or 
decayed vegetation and often approach a heavy peaty nature. The 
rocky areas are chiefly of gravelly sandstone soil and quartz to jagged 
limestone, in some places volcanic. On the coast range permanent 
frost occurs 1 to 3 feet below the surface, and in some sections, as 
at Kotzebue Sound, Wainwright, and Barrow, solid ice is frequently 
found immediately along the coast at a depth of 2 to 3 feet. 
A FORAGE FACTOR 
Lichens vary considerably" in their habitat requirements. Some 
prefer rocks or stones, some the bark of trees, some the soil, and 
others the mosses, decayed herbaceous vegetation, decayed wood, or 
shrubs. Again, some prefer a sandstone rock, others a limestone or 
quartz. Of lichens which grow on the ground, some prefer moist 
peaty soil, some a calcareous soil, some silicious, some argillaceous, 
and some a hardened mud. Thus the soil and ground conditions 
determine in a measure the lichen cover and control protective man- 
agement of the forage type. In Alaska the best lichen growth for 
