Pruning Young Trees
I was recently asked to prune two young trees about 10 feet tall. One had a major branch at about waist height which was almost as large as the main trunk. It looked like a double tree with side branches on both trunks. The other tree had a number of branches at about chest height. Then there was a gap with no branches followed by several branches at about 8 feet. The lower branches were irregular in length making the tree look lop-sided.
Pruning young trees when they are about 8 to 12 feet tall can make a big difference in their appearance and health. Pruning at an even younger stage can be helpful in correcting major defects.
The double trunk tree was growing at an angle of about 25 degrees between the trunk and branch. This means it has a weak attachment which could break in a storm and split the tree clear to the ground. When a young branch grows straight up and begins to look like a second trunk, it can be removed clear back to the trunk. If removed after it has grown too large, it will remove too many side branches and give the tree a lop-sided look. So we shortened it back by about half just above a major side branch. This reduced its weight and susceptibility to storm damage.
I like to shorten branches below 6 feet on a young tree to about a foot in length. These branches will be removed later after the tree has grown taller. By shortening them, they do not grow as large and leave a smaller wound when they are removed. Their leaves produce food which increases the diameter of the trunk and encourages growth of the upper part of the tree.
We shortened the extra long branches on the second tree by about 1/3, pruning just above side branches. They were too large to shorten any more. They can be shortened more next year and removed after other branches above them have developed. Some of the upper branches were also shortened or removed. Branches which grew inward or straight up were removed. Outward growing branches with wide crotch angles (angle between the side branch and trunk) were shortened. Shortening branches above and below the area without branches will encourage branch growth in the area between.