Tuesday, April 4, 2017

Cleaning up a bark graft

   Whenever I graft a tree, I usually return to the new graft every 3-4 weeks throughout the summer to prune off trunk sprouts and root suckers. I also like to start training the new scion to grow a strong central leader. The photo at right is an example of a successful bark graft that I made last year but totally overlooked the all summer training. You'll even note that the graft union is still wrapped in aluminum foil and plastic. To get this tree back into shape, I needed a chainsaw, pruning saw, and hand shears.  
   The first step in cleaning up the this young grafted tree was to cut off all the root suckers with a chainsaw and use the hand pruning saw to remove the trunk sprouts. With just these few cuts I've already reclaiming my grafted tree (photo at left). 

    When I grafted this tree last year, I placed a single scion under the bark of the stock tree. At that time, the stock was about 3 inches in diameter  (photo at right, grafting knife set on trunk for scale). Once the graft took, the scion grew vigorously sprouting numerous new shoots. Unfortunately, none of the shoots from scion produced a strongly dominate central leader. This  scion needed pruning desperately to carve out a single tree trunk.

    In pruning the scion, my first step was to trim the stock at an angle to encourage rapid wound closure. To make the cut, I used a small chainsaw to cut the stock tree at a angle of between 30 and 45 degrees (photos above). Not only does this angled cut enhance  healing,  it also encourages water to run off the wound, promoting rapid wood drying and helping to inhibit wood rot.

  Next, I used my pruning saw and clippers to prune the scion into a single shoot (photo at left). Later this summer, I'll need to train this one remaining stem to grow into a strong central leader tree. By removing all of  root suckers, stump sprouts, and more than one half of the scion's shoot growth, this tree will have a lot of pent up energy to sprout new growth come this spring. I will definitely need to revisit this tree with my pruning shears on a regular basis (every 3 weeks) to direct all new growth in the right directions. I'm positive that new trunk sprouts and root suckers will try to grow this summer. But this time,  I'll be quick to prune them as soon as they develop.

   The photo above gives you an idea of what the tree looked like before pruning and then after I had carved out a central leader. At this point it looks like I've pruned the tree into a telephone pole. However, I assure you, that with proper directive pruning, lateral branches will form and the tree will begin to fill out.