UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1291 
Washington, D. C. 
February 20, 1925 
ASPEN IN THE CENTRAL ROCKY MOUNTAIN REGION 
By Frederick S. Baker, Forest Examiner, Forest Service 
CONTENTS 
Page 
Introduction 1 
Distribution 2 
The tree 5 
Leaves 5 
Flowers and seed 5 
Form 6 
Bark 6 
Root system 7 
Climatic requirements 7 
Soil and moisture requirements 12 
Quality sites 12 
Tolerance '. 14 
Susceptibility to injurious factors — 14 
Fungi 15 
• Insects 16 
Mammals 17 
Fire 19 
Climatic factors 20 
Reproduction 20 
Reproduction of conifers as- 
sociated with aspen 23 
Page 
The stand 24 
Associated species 24 
Growth 25 
Height growth 25 
Diameter growth 26 
Volume growth 27 
Yield 28 
Thinning 31 
Properties of the wood 33 
Uses 33 
Lumbering and logging 34 
Management of aspen, silvicultural 
systems 35 
Relative values of aspen and 
conifers in management — 36 
Transformation of aspen type- 39 
Applied management in the 
field 40 
Appendix 42 
INTRODUCTION 
The detailed studies reported in this bulletin were carried out 
chiefly on the Ephraim Canyon watershed of the Manti National 
Forest in central Utah. (PL I.) The results, however, in a very 
general way, cover the aspen in the entire central Eocky Mountain 
region, including Wyoming, Colorado, Utah, Nevada, southern 
Idaho, and a little of northern Arizona and New^ Mexico. More 
general observations made personally by the writer throughout 
Utah, southern Idaho, and western Wyoming, indicate that the re- 
sults obtained in central Utah are generally applicable throughout 
that entire region. The climatic, topographic, and ecological simi- 
Note. — The writer wishes to acknowledge the valuable assistance rendered in this 
work bv the parallel studies, on the subject of decay in aspen, conducted in the same 
region under the direction of Dr. E. P. Meinecke. The unpublished manuscript report 
of this work was placed at the writer's disposal. The discussion of the pathology of 
aspen, down to and including Table 7, page 14, is based on the report of Doctor 
Meinecke. 
2023°— 25 1 
