REVIEWS 



Effect of Grazing upon Aspen Reproduction. By A. W. Sampson. 

 Bulletin 741, U. S. Department of Agriculture. Contribution from the 

 Forest Service. \\'ashington, D. C. 1919. Pp. 29. 



There was a time when the inquiry suggested by the title of this 

 bulletin would have been answered by a wholesale generalized experi- 

 mental judgment and be left at that. Nowadays, however, when the 

 proverbial man from Missouri is about, wanting "to be shown," noth- 

 ing short of experimental demonstration and detail statistics, carefully 

 ascertained, will satisfy the inquirers. And, as a rule, by such method 

 more than the original question is answered, as in the present case. 



The basis is furnished by some 120 sample plots observed and meas- 

 ured up for five years (a misprint on page 2 makes it 15 years). Clear- 

 cut and lightly thinned areas, different-aged growth, and varied inten- 

 sity of grazing by sheep and cattle were involved. 



We note that apparently no reproduction by seed takes place, but 

 only sprouts from the stump seem to furnish the reproduction. 



In Utah, where the study was made, and in some other sections of 

 the Northwest, the aspen, which usually is looked upon as a transitory 

 type, becomes a permanent source of much valuable material; hence 

 the question whether and how to make it serve the double purpose of 

 meat production and wood production. Sheep are doing severe damage 

 to young growth in standing timber, as well as in clear cuttings, to an 

 extent of 27, 32, and 65 per cent, respectively, according to the inten- 

 sity of grazing, while cattle cause under same conditions only 1.6, 2.4, 

 and 26.8 per cent. As a rule, three years of successive sheep-grazing 

 on clear-cut lands results in the destruction of the entire stand, a nota- 

 bly greater proportion of the woody stems being consumed by sheep 

 than by cattle. 



"On lands protected from grazing, aspen sprouts are produced only 

 during the first two seasons after cutting. On grazed lands a consid- 

 erable number of sprouts are sent up for three successive seasons fol- 

 lowing the removal of the timber. The third year's reproduction, how- 

 ever, appears from two to five weeks later than that produced in the 



703 



