In order to interpret and apply results, a few definitions of terms and 

 explanation of treatment techniques are needed. Figure 1, a schematic diagram 

 for denoting annual growth of a balsam fir tree should assist in this explanation. 



Terminal treatment of which tip pruning was one treatment, consisted of 

 shortening the current leader growth by cutting it back to near the point where 

 lateral branches (the topmost whorl of branches) meet the leader when these 

 laterals are bent up to meet the leader. The leader was cut off about % inch 

 above an internodal bud at or near this point. The 90° cut was made 

 perpendicular to the stem axis, and the 45° cut at that angle to the axis. Such 

 terminal treatment is based on the premise that reduced internodal length would 

 result in an increased tree density, as the lateral whorls would then be less widely 

 spaced. Cutting angles and season of application were expected to have an effect 

 on subsequent terminal bud development. Since random selection of trees was 

 the rule, a few trees having short terminals did not require and therefore did not 

 receive a tip pruning. 



Maleic hydrazide is a chemical that was applied to a terminal bud either in the 

 spring or the fall, in a 0.1 percent water solution. It was hoped that maleic 

 hydrazide would inhibit leader growth by altering hormone balance without 

 adversely affecting tree form. 



Another terminal treatment, root pruning, was done through four cuts into 

 the soil outward from the tree stem, two thirds of the distance to the crown drip 

 line. Each cut was made straight into the ground to the full depth (12 inches) of 

 a No. 2 round pointed shovel blade. The intent is to reduce terminal growth by 

 reducing the root area of a tree. 



Lateral treatments consisted of clipping and shearing lateral branches and 

 were intended (as were terminal treatments) to be applied annually either in 

 spring or fall. Clipping was originally interpreted to be removal of the primary 

 lateral-terminal growth that had been added to the tree branches during the 

 previous year (see Figure 1). Clipping was confined to one year old wood in the 

 1964 first annual treatment and performed on the entire tree except for the top 

 or current year's whorl. The practice was intended to produce a fuller tree by 

 having the lateral-lateral growth contribute more "tips" to the periphery of the 

 tree (refer to Figure 1). In theory, for every "lateral tip" which is cut off 

 (clipped) there should be two lateral-laterals producing tips the following 

 growing season. (Results indicate that this happened to a large degree). In 

 applying the treatments, whenever secondary lateral-terminal growth contri- 

 buted to filling in the outer surface of the crown, it was also removed. 



In practice, clippings subsequent to the initial 1964 treatment were changed 

 in that only bud clusters on primary lateral terminals were removed and wood 

 was left intact. This variation for 1965 and 1966 resulted in trees of fuller 

 appearance and accomplished the purpose in clipping. 



