22 



BULLETIN 741, U. S. DEPARTMENT' OF AGRICULTURE. 



serious damage by sheep and cattle, (1) the rate of growth of the 

 reproduction and the age at which the major portion of the stand is 

 exempt from serious browsing, and (2) the density of the stand that 

 may be expected, and accordingly the extent of thinning, if any, 



I 



90,000 



10,000 



60,000 



SO, 000 



40,000 



iO 

 40 

 30 

 20 

 10 

 











^ 







_._-_ 



^ 



" 







— — -~ yy 













/ _/■■*"" 















^-^^^^ 















* 



! 



!"5 30,000 





20,000 



10,000 





1 



s 





1 



1 

 1 







1 

 1 







1 

 1 



1 



\ 



s 



\ 











"""--^ 



\ 

 \ 







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/ 1 





1 



1 1 _ 







— ■ 









/ 1 





i 



1 



1 













2 







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t 







i 











Fall Spring Fall Spring Fall Spring Fall Spring Fall 



1912 1913 1913 1914 1914 1915 1915 ./9/G 1916 



Spring Cuffing 



Summer Cuffina 



Faff Cuffina 



Fig. 7. — Number of sprouts and average height growth according to season of cutting. 



that may be permitted by browsing and that will leave enough 

 reproduction to secure the number of trees which the lands will well 

 support. 



To determine the sprouting capacity of aspen and the corresponding 

 vigor and rate of growth of the resulting sprouts when the lands are 

 clear-cut in different seasons, the timber was removed on three plots 

 of even-aged aspen, each one-half acre in size. One of the plots was 

 clear-cut in the fall of 1912, another early in the spring of 1913, and 

 the third in midsummer 1913. In Table 10 is summarized the number 

 of living sprouts per acre on these plots and the height growth per 

 season according to the time of cutting. To facilitate comparison of 

 results the data are assembled graphically in figure 7. 



