Published November 28th, 2010
Winter is the best time to prune trees. There are some simple and easy steps you can take to train young trees. The worst tree defects can be fixed, without climbing, when your trees are still young. In winter it’s easy to spot where the problems are, and winter pruning is not harmful to trees because they are dormant.
A common defect to look for is called a “bark-included crotch”. This defect occurs when, instead of a healthy limb attached to the trunk, a tree forms a close crotch (see illustration). As the tree grows, bark is “included” between the limb and trunk, or the tree forms competing trunks with bark between them. The limb and trunk are not really attached, since the bark forms a seam down inside the tree. As the tree grows and the limb or second trunk gets heavier, this hidden weakness becomes more dangerous. The tree may simply split in half by gravity, but usually it’s an ice storm or heavy wind that finally sends the limb crashing down.
The best and easiest time to fix bark-included crotches is when they first occur on young trees, before the limb is thicker than your thumb. You can simply cut the offending limb off at the crotch and it will heal over in a single season. Bigger limbs are harder to cut through and take longer to heal, but the longer you wait the worse the problem. Deal with it now.
To cut tree limbs properly make three cuts: 1. Make a cut on the underside of the limb an inch or two above the spot where it meets the trunk. This will prevent tearing or peeling of the bark when you cut the limb off. 2. Cut downward from above, a few inches further out on the limb, until it falls. This will leave a short stub. 3. Cut the stub off. Make the cut straight across the remaining limb, not parallel to the trunk. The exposed end should be round, not oval. Leave enough of a stub so that you don’t damage the “branching collar”; the wrinkled flare of bark around the base of the limb. This will then grow and quickly cover the open cut. Never leave a stub longer than a half-inch, because the bark can’t heal over your cut and this invites tree problems.
The reason for cutting in three steps is that you can’t cut at the right angle from above, because the tree trunk interferes with your saw. The final cut has to be made from below. The heavy branch will cause your saw to bind in the cut and get stuck. By cutting most of the limb off first, you take the weight off so you can make the final cut easily and precisely.
Many people are afraid to prune or cut trees for fear of damaging or killing them. This fear prevents them from making simple corrections when they’re easy to make. Remember “a stitch in time saves nine”? Get over your fear and you’ll actually have healthier, stronger trees. You’ll be amazed how proper pruning cuts heal over without a trace. Once you see this work you’ll be proud of yourself.