B. Results of Cultural Practices Study— Main Plots 



The overall result of cultural practices on a Christmas tree is expressed in a 

 change in tree grade, which is a relatively subjective criterion. What is the 

 reaction of the beholder to the tree? At the beginning of the study the trees 

 were graded on a scale ranging from 6 (excellent) to 1 (very poor) and a grade 

 comparison made three years later. The Appendix explains the grading system, 

 which took into account the components of crown symmetry, crown density 

 and crown taper in arriving at the tree grade. Color was not included in the 

 grading. However, tree color was not significantly affected by terminal or lateral 

 treatments, but rather by fertilizer application.Treatment effect on tree form was 

 also evaluated by recording a three year change in a subjective internodal branch 

 rating, also on a 6 to 1 rating scale. 



Components which are used to judge tree form on a quantitative basis are 

 internodal length, branches per whorl, and lateral tips. Terminal treatments 

 affected internodal length. Changes in internodal length can be looked at for 

 evaluation of these treatments. A terminal treatment that is successful in 

 shortening internodes that are too long may not be a desirable cultural practice 

 if there are fewer branches in the subsequent year's whorl, or if it results in 

 fewer lateral tips, or in poorer internodal bud development. 



Lateral treatments had a direct effect on the components of tree grade. One 

 quantitative measure that is fundamental to tree grade is the number of lateral 

 tips. The changes brought about by treatments were significant. At this point, 

 the effects of terminal, lateral and fertilizer application will be separated to some 

 extent, but in actuality they are interrelated. 



1 . Terminal Treatments 



It is obvious that a physical cutting back of a terminal by tip pruning 

 would be effective in controlling leader growth, but the root pruning and spring 

 maleic hydrazide treatment was also effective. Fall application of maleic 

 hydrazide was not effective. 



As a basis for this judgment, the internodal lengths (representing height 

 growth) for the 1961-63 years were subtracted from those of the 1964-66 years. 

 For the effective treatments, then, some of the side effects need to be examined. 



During preliminary work to the experiment it was suspected that fall tip 

 pruning might reduce the number of branches counted in the new whorl 

 following pruning. Statistical analysis was made of the whorl branch changes 

 with terminal treatments in the experiment. In this, the number of branches in 

 the 1964-66 whorls were compared to the numbers in the pre-treatment 1961-63 

 years for individual trees in each treatment. The results were conclusive in that: 



a. root pruning and fall maleic hydrazide did not differ much from the 

 control tree performances. Whorl branching about held its own in this group. 



b. other spring treatments tended to reduce whorl branching with a drop 

 off of one to two branches total over the three year period, with spring maleic 

 hydrazide performing most poorly in this group. 



c. fall tip pruning cannot be recommended because of a marked drop off 

 of four branches over a three year period as against the control. 



8 



