SINO-MONGOLIAN FRONTIER 
Spruce (Picea sp.) and Larch (Laryzx sp.). These 
trees occur at altitudes of from 5,000 feet upwards, 
usually growing on slopes exposed to the north, 
which, remaining snow-covered all the winter 
and late into spring, are always more moist than 
those facing south, where the snow usually melts 
a few hours after it has fallen. Though these 
forests are often very extensive, the trees seldom 
attain a growth of more than two feet in diameter. 
Large areas of forest, consisting of one or other 
of these species, is the rule, but not infrequently 
mixed forests occur. 
The lower slopes in these forest areas are often. 
clothed with the Common Pine (Pinus sylvestris), 
while it is nearly always this tree that goes to 
make up the woods round temples in the foothills. 
This tree is prized above either of the foregoing 
species as a wood producer. The woodcutters 
strip the saplings of their lower branches, which 
causes them to grow very tall and straight. 
In Shansi one also comes across the peculiar 
White-barked Pine (Pinus bungeana). It is char- 
acterized by having a three-needled leaf, and by 
its smooth silvery-white bark. This tree is very 
rare indeed. 
In Shensi I came across a small member of the 
genus Pinus, which grows on rocky cliff surfaces, 
and is characterized by having five or seven needles. 
This also seems to be a rare species. 
In the foothills and on the plains of Shansi and 
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