394 JOURNAI, OF FORESTRY 



made in summer, however, there is no sprouting until the following 

 year, and even when made in the spring, although there is considerable 

 sprouting during the year of cutting, the maximum does not occur 

 until the year following. In all three cases the result is the production 

 of a large number of hardy sprouts. The small number which start 

 late in the season always are frozen back and usually killed by the 

 first frosts in the fall. The maximum density of sprouting is greatest 

 from spring-cut stands, 85,520 sprouts per acre being found upon the 

 spring-cut plot under observation, at the end of the second growing 

 season, while the fall-cut plot showed a maximum of only 41,700 at 

 the end of the first growing season. The summer cutting resulted in 

 about the same amount of sprouting as the fall, with a maximum of 

 50,960 after one and one-half growing seasons. It is evident that 

 these numbers are amply sufficient to restock the area to full density, 

 as 480 trees per acre is the average in mature stands. The loss from 

 suppression was much the highest on the spring-cut plot ; and now, after 

 four years, all three plots are approaching the same number per acre, 

 having between 20,000 and 30,000. Height growth has been little 

 affected by the season of cutting. Sprouts from fall cutting main- 

 tained the lead up to the fourth year, when those from the summer- 

 cut stand slightly surpassed them. The sprouts from spring cuttings 

 have grown a little more slowly than those on the other two plots, un-» 

 doubtedly on account of the extreme density of the reproduction in 

 this case. The average height of all is now between 41 and 46 inches. 



Effect of Cutting Stands of Different Ages 



The age of the parent stand is another factor which usually affects 

 the amount and vigor of sprouting to a great extent. This was in- 

 vestigated by cutting stands 70, 90, and no years old, respectively, as 

 these ages include the sizes of aspen which are now generally utilized. 

 All three stands were cut in the fall of 1914, and in the fall of 1916 

 showed the following conditions:. 



Average Number of Number of Number of 



... d. b. h. groups sprouts sprouts Average 



Age ot stana. parent of sprouts per per height, 



stand. per acre. acre. group. 



Years Inches Inches 



70 5-37 27,622 66,772 2.42 19.3 



90 3-44 40,020 94,622 2.36 15.4 



no 5.17 12,615 36,540 2.90 19.3 



As these three plots were located on very different sites and at dif- 

 ferent altitudes, the sprouting has been greatly affected by other factors 

 than the age of the stands. 



