758 JOURNAL OF FORESTRY 



vertically for several hundred feet, whence the country falls away until 

 the base is reached after a descent of i6 miles to the town of Escalante, 

 5,750 feet high. Around this truncated cone, as elsewhere in the re- 

 gion, the cover types occur in parallel altitudinal zones and stand out 

 clear and well defined as listed from the lowest to the highest : 



1. Sagebrush. 



2. Cedar and pition mixed. 



3. Oak brush, coincident with the yellow-pine belt. 



4. Pure aspen. 



5. Aspen and alpine fir mixed. 



6. Pure Engelmann spruce (on top of the plateau). 



This is a typical example of the relative position of the types in 

 which pure aspen lies between the brush or chaparral — yellow-pine 

 type and the alpine conifers. Numerous other localities might be 

 pointed out in which aspen shows its true relation to the other species 

 and types ; sometimes one conifer is more prominent, sometimes an- 

 other, but aspen almost invariably occurs in pure stands at its lowest or 

 first occurrence and more or less mixed with conifers at its upper 

 limits, whence the conifers extend to altitudes where aspen cannot 

 follow. 



Examples of the occurrence of pure aspen considered permanent are 

 found at the head of Gooseberry Creek, on the Fishlake National For- 

 est, near the Grazing Experiment Station ; in the park country on the 

 Manti extending northward from Upper Joes Ranger Station to Bulger 

 Canyon; near the Tony Grove Ranger Station on the Cache and on 

 Cottonwood watershed on the Cassia Division of the Minidoka. 



The writer holds that there is no conifer in the district with exactly 

 the same requirements and qualities as aspen ; hence there is left a strip 

 or belt, as it were, in which no native conifer can replace it, with or 

 without the help of a fire, just as there is a belt in which tree species 

 cannot compete with sagebrush, with Engelmann spruce, or lodgepole 

 pine, even though fires are prevalent. While aspen is considered as a 

 permanent forest type in many places, it is admitted that it will alter- 

 nate with alpine conifers in its upper limits where it mingles with them 

 and the two overlap. 



The main arguments in support of the permanency of aspen as a 

 type outside of observation will be taken up briefly. 



Aspen is a prolific sprouter. Whenever an opening occurs in any 

 present stand, whether due to fire, old age, or accidents, it is promptly 

 filled again by new root sprouts. As shown by clear-cutting experi- 



