Native: Ve;ge:tation 
53 
Fig. 19.—On the South Fork of the South Platte River, altitude 
about 8,000 feet. Hill slopes clothed with typical yellow pine. Alfalfa 
and small grain in the cultivated area. 
and alfalfa (Figs. 19 and 20) are both well-suited to the yellow 
pine zone. Smith* has shown that the potato makes its best de¬ 
velopment in those sections of the country where the mean annual 
temperature is between 40° and 50°, and where the mean for July 
is not over 70°. Reference to the climatic data for the yellow 
pine forest community shows a range of the mean annual tempera¬ 
ture from 40° to 47°, and the mean for July 62° to 67°. The har¬ 
dier cane fruits and strawberries are usually a success, except in 
the higher parts of the zone. All of the hardier vegetables, such 
as onion, carrot, parsnip, parsley, beet, radish, lettuce, turnip, cab¬ 
bage, rutabaga, rhubarb, mangel-wurzel, pea, and early sugar corn, 
do well. Tomatoes, cucumbers, peppers, beans, and other tender 
vegetables are grown with success only during the most favorable 
seasons, or in the lower part of the zone. 
LODGEPOLE PINE FOREST ZONE 
Distribution and Vegetation .—Lodgepole pine ( Pinus murra- 
yano) is bounded on its lower edge by the yellow pine forest and 
on its upper by the Engelmann spruce-balsam fir forest. Its usual 
altitudinal range is from 8,000 to 10,000 feet. However, its verti- 
*The Effect of Weather Upon the Yield of Potatoes, Monthly Weather Review Vol. 
43, No. 5, pp. 222-236, 1915. 
