28 GUIDEBOOK OF THE WESTERN UNITED STATES. 
Above Dawson Butte the railroad continues up the valley of East 
Plum Creek, winding around a projecting spur of the plateau on the 
east to the village of Larkspur, from which a stage 
Larkspur. 
Elevation 6 a feet. west. 
Denver 43 mil 
line runs to the resorts in Perry Park, 4 miles to the 
This is a natural parklike area at the foot of 
e mountains, made picturesque by natural monu- 
the moisture falls as snow during the 
inter. The presence of trees con- 
trols and prolongs this stream flow by 
preventing erosion and retarding the 
melting of snow in the spring and 
early summer, 
The forest on the mountains is com- 
posed of many differen aa 5 sa of 
trees, and the range in elevation of 
thene species is si pias _by 
e the zone of yel- 
low pine is the zone <a lodgepole pine 
Pl, XXXYI, B, p. 76) and above this, 
extending to timber line, is the zone 
in which Engelmann spruce (PI. XIII, 
fi j 
aspen oc 
This tree, which 
‘presents a wonderful richness of au- 
a marked tend- 
fers that require more moisture start 
to grow and ultimately take possession 
_ found in the moist stream bottoms, in 
the zones of the yellow pine and pifion, 
and out on the plains, 
One e, the white * i Sra toote pines 
grows on exposed s eee Zt bak 
zone of ota ay ie. 
which is called limber pine, go bony 
commercial value but is very pic- 
turesque because of its gray-green 
foliage and whitish bark. Its pal 
yellow cones are larger than those of 
by the severe climatic conditions un- 
der which they grow 
In the zone of the lodgepole pine 
rives its names from the recurv 
prickles or thorns at the extremity of 
and from the exuda- 
tions of — on the surface of the 
es, which when dry look 
very si eit particles of 
To maintain a cover for an even ~ 
stream flow and protect the supply of 
timber all the more extensive drainage 
asins of the United States have been 
included in national forests. There 
are seventeen such forests in Colorado, 
comprising over 13,000,000 acres of 
mountainous country. 
A forest, which is based upon nat- 
ural subdivisions and administrative 
i=" 
50,000 to Such districts 
lice 
taining to the national f 
Pike National Srey ‘includes : : 
000, 
their domestic water supply. In addi- 
Pal pc ae 2 is ne ei 
