CURRENT LITERATURE 
NOTES FOR STUDENTS 
Applied ecology.—Increasing attention is being paid to the application of 
ecological principles to problems in plant and animal agriculture, horticulture, 
and forestry. Among the more important recent papers in this field are 
three contributions by Sampson,! and one by SAMPSON in conjunction with 
Wevu.? The first of these is an attempt to show a correlation between climate, 
vegetative associations, and crop production. Stations for instrumental 
work were established in the Manti National Forest of Utah at three different 
elevations, one in the oak-brush association which ranges from 6500 to 7800 ft. 
in altitude, a second in the aspen-fir association which ranges from 7500 
to 9500 ft., and a third in the spruce-fir association which ranges from 9000 
to 11,000 ft.. The plants used in the experiments were field peas, Kubanka 
wheat, and the mountain brome grass (Bromus marginatus). Measurement 
wi 
growth and water requirement. The number of growing days varies from 
120 at the lowest to 70 days at the highest station. The greatest rainfall is 
at the middle station, being about twice that of the station below. The 
evaporation is greatest at the lowest station, but is almost as great at the 
highest station, owing to wind velocity. The necessary effective heat units 
for wheat and field peas exist only at the lowest station, where the water 
supply is inadequate unless supplied artificially. 
AMPSON’S paper on plant succession in relation to range management is 
a peculiarly apt illustration of the importance of ecological principles in the 
treatment of range lands. To most agriculturists it would seem a far cry 
from an academic study of plant succession to the practical treatment of range 
land and pasture, but Sampson makes it very clear that the relation between 
the two is fundamental. Stockmen have generally recognized that over- 
grazing is a common result of their practice, but they have for the most part 
been unable to detect overgrazing in time to stop the damage. SAMPSON has 
™ Sampson, Artuur W., Climate and al otaber in certain vegetative asso- 
ciations. Bull. 700, U.S. Deut. Agric. pp. 72. figs. 37. 1918. 
, Plant — in relation to range siidccbeaa: Bull. 791, U.S. Dept. 
Agric. pp. Wo: pls. 2. figs. 26. 1919. : 
» Effect of a upon aspen reproduction. Bull. 741, U.S. Dept. Agric: 
pp. Ke pls. 5. Bic 7. 1919. 
d Wevt, L. H., Range preservation and its relation to erosion con- 
trol on Re oui lands. Bull. 675, U.S. Dept. Agric. pp. 35- pls 6. figs. 8. 1918. 
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