Figure 4. — Paired trees were 

 used to determine effects of 

 basal pruning on Christmas 

 tree production: the lower 

 two-thirds of the green crown 

 was removed on the tree on 

 the left; the tree on the 

 right served as a check. 



All three thinning treatments were installed at each of five locations, making a 

 total of 15 plots. All plots were 1/100 acre in size and were surrounded with a 15- to 

 20-foot wide isolation zone. Treatments were randomly chosen. Dominant and codominant 

 trees in the thickets averaged 15- to 19-feet tall when the study was started. 



STUDY RESULTS 



Stump culture was the most successful treatment tested in this study, producing 

 large numbers of trees that were above average in both quality and size. None of the 

 pruning methods significantly (t-test, 1 percent confidence level) increased total 

 Christmas tree production. Heavy thinnings produced the most trees initially, but 10 

 years later the light and moderately thinned areas still had three times as many trees 

 capable of producing Christmas trees. 



Stump Culture 



A comparison of the two types of stump tree origins--branch turnups and adventi- 

 tious shoots--demonstrated that over three times (significant at the 1 percent level by 

 t-test) as many turnups developed into Christmas trees as shoots. As shown in table 1, 

 59 percent of the stumps treated to favor branch turnups produced Christmas trees. 

 Meanwhile, 17 percent of the stumps treated to favor adventitious shoots produced 

 Christmas trees. 



Year of stump treatment had no apparent effect on tree production because the 

 number of trees produced from branch turnups varied only slightly by years (table 1), 

 Production from adventitious shoots was slightly more erratic, but no pattern was 

 apparent , 



5 



