REFORESTATION IN NORTHERN ARIZONA. 



E. W. Nelson '13. 



Large areas in Northern Arizona once forested are at pres- 

 ent not growing trees. Since timber is the most valuable crop 

 that can be grown on many of these areas, reforestation presents 

 an important problem. Natural reforestation of these denuded 

 areas is practically impossible and artificial reforestation must 

 be resorted to. 



The altitudinal range of this region varies from 3,500 feet 

 at the southern extremity of the Colorado Plateau to 12,800 

 feet at the summit of the highest peak of the San Francisco 

 Mountains in the north central part. The southern part is dis- 

 sected by numerous deep canyons; while the northern part is 

 dotted with many volcanic cones. The general slopes of the 

 region are toward the northeast and sonthwest, the northeast 

 slope descends gradually with but few breaks toward the Little 

 Colorado River, while the southwest slope is quite gradual until 

 it drops off precipitously into the Verde Valley. 



The soil typical of this region is of four kinds, as follows : 

 gravelly loam, or malpais soil, consisting of loamy or adobe con- 

 stituents mixed with considerable volcanic debris ; the limestone 

 soil covers rather extensive areas ; loamy gravel, which occurs 

 in the limestone belt, and in the northeast portion in the desert 

 areas ; and cinder soil, which is a mixture of volcanic cinders 

 and clayey loam, occurring in the volcanic region surrounding 

 the San Francisco Peaks. 



The climatic conditions existing in this region are not favor- 

 able for natural reproduction. The annual precipitation aver- 

 aging about twenty inches falls chiefly during the winter and 

 late summer months, with a dry period in the spring and another 

 in the fall. The dry season of spring extends from April to July 

 during which severe southwest winds prevail. These winds 



