Tree Trimming Guide: Weak Crotches

A branch can appear leafy and healthy, but its growth habit could be a problem. Weak crotches are an issue that can increase the chances of branches blowing down in storms or breaking off due to their weight. Knowing how to recognize a weak crotch and how to properly trim out the branch increases the health of the tree. 

What Is a Weak Crotch?

The crotch refers to the angle at which a branch joins the trunk. Ideally, the angle formed will resemble the letter "V" with the branch arching upward from the trunk. 

There are two situations that lead to a weak tree branch crotch. The first is the overly wide crotch, which refers to a tree branch that droops downward so that the crotch angle is obtuse. The other situation is when the angle is too tight so that the branch is almost vertical to the trunk. Basically, the angle should be in the range of 90 to 45 degrees so that it forms the necessary healthy "V."

When Should It Be Pruned?

Pruning is best done when the branch is still fairly young, as thick older branches can be more difficult to prune without the aid of a saw. Larger branches are also more likely to cause damage if they fall, and a weak crotch leads to an increased chance of breakage and falling. A branch can easily be snipped off with bypass shears if it is still smaller than the thickness of your thumb, and usually at much less risk.

Ideally, this pruning will take place in late winter or early spring, when the tree is still dormant. Pruning during dormancy is less likely to cause stress to the tree. If the branch is posing a danger, such as a large branch with a wide crotch that could fall and cause damage below, then it should be trimmed regardless of the time of year.

How Is It Properly Trimmed?

A clean pruning cut is a must; otherwise, the tree could be left susceptible to fungal or disease issues. Always use sharp, clean tools so that the cuts are clean and more likely to seal over quickly.

Cuts should be made flush to the trunk. Larger branches may have a slightly raised bark collar where the branch joins the trunk. In this case, make the cut flush to the collar. 

Contact a tree trimming service if you notice weak crotches in the crown of your tree.