Tuesday, July 12, 2022

Young tree's growth response to spring time directive pruning

    In previous posts, I've stressed the importance of practicing directive pruning during the spring flush of growth to encourage the development of a strong central leader. The photos at right show the pruning cuts I took back in late May of this year. At first glance, it looks like I'm trying to create a single-stemmed tree with no side shoots.
However, that is not the case at all. These early-season pruning cuts are designed with the single focus of promoting a single central leader. New lateral branches will develop, but later in the season and at much more desirable branch angles. 
  In mid June, I returned to the tree that I pruned in May. In the photo at left you can see that I have successfully maintained a single central leader. But you should also notice that there are now numerous lateral shoots sprouting out from the trunk all below the new central leader.
     On closer inspection (photo at right), you will note that the new lateral shoots are growing from secondary buds that are located just below each pruning wound (the pruning cuts I made in May). It is also important to note that these new shoots are growing out at a wide angle from the trunk. These shoots will develop into strong well-anchored branches that resist wind and ice breakage.
    By early July, all of the new lateral limbs are growing nicely (photo at left). It won't be long before I have well bushed out tree all while keeping a single central leader. I'll leave all these lateral branches on the young tree to help promote trunk diameter growth. The increased leaf area on the trunk catches more wind which, in turn, promotes a strengthening and thickening of the trunk. 

    Young, rapidly-growing trees need training throughout the summer months. Pruning cuts made to strengthen the dominance of the central leader usually means that stalked buds will start to form in mid-summer on the central leader near the top of the tree. Left to grow, stalked buds will produce narrow-angled branches that develop a bark inclusion at their base. If all the stalked buds that form on a central leader are allowed to grow, a pecan tree will become top heavy and take on a broom-like appearance (at the top of the tree). I pinch off all stalked buds as soon as I see them to preserve the central leader (photo above).