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How to Seal the Crotch of a Damaged Tree

split tree image by Dave from

Ornamental and shade trees are frequently damaged by storm winds and the weight of ice and snow, particularly if they are soft-wooded varieties or if the tree is structurally weak and splitting under its own weight. Assess whether it's worth it to try to save a large, mature tree with a split crotch. If you decide to go ahead, there are a number of things you can do to repair a split crotch. The goal is to pull the sides of the split together and let the tree self-seal.

Step 1

Reduce the weight on the branch that is splitting from the crotch by pruning a third of its foliage away with pruning shears. If the split is low on the trunk of the tree, prune upper branches from the weaker side.

Step 2

Raise the weaker side of the tree to join the sides of the split together. If the tree is large, use a block and tackle. If the limb is small, lift and secure with cable or a length of clothesline. Think of it as putting a broken arm in a sling.

Step 3

Get several long, threaded brace rods with nuts for either end at the hardware store. Drill a hole through both sides of the split using a drill bit that is 1/16th-inch larger in diameter than the rod. If the split is deep, install more than one brace rod.

Step 4

Install the rod, tapping it through the hole with a hammer. Cap both ends with nuts, and screw them down tight with a wrench.

Step 5

Carefully cut away loose or torn bark from the sides of the split with a sharp knife. Seal with pruning paint to prevent the bark from drying out over the next few months as the split seals and heals by itself.

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