28 BULLETIN 141, U. S. DEPARTMENT OF AGRICULTURE. 



by the consumption of the herbage the fire risk to the timber may be 

 greatly minimized. 



Being unable to reproduce in its own shade, aspen must be well 

 opened up either by heavy thinnings or by clear-cutting, preferably 

 the latter, if the lands are to be fully restocked. 



When the logging is done on sheep range, or on a combination 

 sheep and cattle range, the forthcoming reproduction will be destroyed 

 almost to the last sprout if the areas are even moderately grazed by 

 sheep during the first three years following the cutting. To avoid 

 destruction of the young aspen cover, then, only three courses are 

 open: (1) Entire exclusion of grazing for three successive seasons 

 following logging, (2) exceedingly light grazing by sheep, and (3) 

 moderate grazing by cattle. 



Obviously, the first of these possibilities does not appeal either to 

 the timberman or the stockman. The entire exclusion of grazing 

 animals means increased fire risk and additional fire patrol, the cost 

 of which must be met by the timberman. For the stockman whose 

 farm operations generally, including to a large extent the marketing 

 of the crops produced, are dependent upon the grazing afforded in the 

 aspen type, entire exclusion of stock may spell ruin. 



The second possibility, very light grazing by sheep, would upon 

 first thought appear to meet the requirements, and guarantee estab- 

 lishment of the reproduction. But the sheepman who will graze 

 his sheep very lightly over the choicest of forage, such as invariably 

 becomes established on clear-cut or heavily thinned aspen lands, 

 has not yet been discovered. Naturally the sheepman's interests 

 lie in the production of the maximum mutton and wool consistent 

 with sustained forage yield; he has little interest in the production of 

 timber. Since the standards of grazing intensity vary with the 

 individual, what may be declared as very-light cropping by the 

 average stockman might be classed as moderately heavy by the 

 grazing expert or the silviculturist. Furthermore, the intensity of 

 the grazing, at least so far as the stockman is concerned, would, of 

 course, be judged by the extent of cropping of the herbaceous cover 

 rather than by the seriousness of the browsing of the aspen reproduc- 

 tion, whereas, owing to the tendency of sheep to browse rather than 

 graze, the aspen would probably be badly damaged before much 

 of the herbage would be consumed. Accordingly only the very 

 lightest grazing, coupled with the most expert handling of the flocks 

 during the first three seasons, could be expected adequately to protect 

 the reproduction, and exceedingly few herders would be qualified to 

 assume such responsible management. 



This brings us to the third course open to avoid the destruction of 

 the young aspen cover; viz, moderate grazing by cattle. The aspen 

 type occupies lands of moderate elevation usually characterized by 



