PRUNING YOUNG TREES 



227 



FIG. 193 PORTABLE BRUSH INCINERATOR 

 Built of sheet iron on runners. Holes in the bottom 

 admit air and allow ashes to fall out. 



no loss of trees through lack of cutting back of the top at the time 

 of planting, as all the unpruned trees were alive at the end of the 

 growing season. 



180. Effect of pruning upon total twig growth. On the basis of 

 a comparison of grades regardless of any pruning treatment the 

 ^j-inch trees made 



the best average 

 total growth, 

 closely followed by 

 the i/^-inch trees. 

 The smallest aver- 

 age total growth 

 was made by the 

 2^-inch trees. A 

 comparison of the 

 various pruning 

 treatments regard- 

 less of grade 

 shows that the best 

 average total 

 growth was made 

 by the trees pruned 

 to 36 inches and 

 the next best by 

 those cut back to 



12 inches. The lowest average growth was made by the trees cut 

 to 18 inches. The unpruned trees made a very creditable and uni- 

 form growth in comparison with the other treatments based on total 

 growth regardless of form. 



181. Effect of pruning growth of dried-out trees. When the dried- 

 out trees were received the bark was much shriveled and the roots 

 in a dried condition, but they were soaked in water for several hours, 

 heeled into moist soil for a few days and then pruned and planted. 

 The same number of trees were used as in the experiment previously 

 noted, except that it was not possible to secure trees of a 7/6-inch 

 grade. 



A record of the number of living trees at the close of the sea- 

 son's growth clearly indicates, as would be expected, that the small 

 trees suffered the most from the drying out in transit. The roots 

 of ^-inch trees are all small and easily dried out. The bark of 

 twigs and trunk of the smaller trees probably also permits more 

 rapid evaporation of moisture than does that of the larger trees. 



One would expect to find the greatest loss among the unpruned 

 trees and the least among the 6-inch trees. This is practically true, 

 but it is worthy of note that the 12-inch treatment and the 36-inch 

 treatment have as high a percentage of living trees as the 6-inch, 

 and that the 18 and 24-inch treatments suffered nearly as much loss 

 as the unpruned trees. This is significant in connection with the 

 comparisons on the basis of total growth in the various treatments. 



