How to Repair a Damaged Tree Trunk

The stately oak tree in the front of your home boasts curb appeal, provides shade during summer months, and offers a place to hang your favorite swing. Because of these benefits, it’s worth learning how to repair a damaged tree trunk after a run-in with a lawnmower or tennis racket. Luckily, learning how to save a tree with damaged bark is fairly easy and can extend your tree’s life for many years to come.

How to Prep to Repair a Tree’s Bark

You should first assess the extent of damage done to the tree’s bark. The damage should make up no more than 25% of the tree; this gives your tree the best chance at survival. If the damage looks to be more than 25%—but under 50%—then your tree might survive. It just might be weaker, with some of the tree’s canopy failing to grow as lush as it once did.

Extensive damage covering over 50% of the tree puts the tree’s survival odds very low; a professional tree service company might be able to perform bridge grafting to bring it back to health. However, saving a dying tree is not always possible, so you should rely on a local tree maintenance professional’s opinion on its chances of reviving.

How to Save a Tree With Damaged Bark

If your tree has only been mildly damaged, you can take some measures to help the tree seal the area, preventing the spread of any tree fungi, bacteria, or other harmful invaders.  

1. Clean the Damaged Area

By tidying up the area where the wound occurred, you can reduce the number of jagged edges, which can hinder the tree’s ability to create a layer of new, calloused tissue.

1. Put on protective gloves and manually peel away the damaged or loose bark.

2. Using a clean chisel and a hammer, carefully cut a clean edge around the wound.

3. Chip away the pieces of bark around the tree wound. Be careful not to create further damage by cutting any deeper.

4. Do not cut any sharp corners; try to cut a round shape. This method will help the wound heal faster.

Note: You may have heard about “dressing” a tree’s wound by covering it with tar or paint. This practice does not prevent decay and might even delay the growth of new tissue. Finally, a tree wound dressing can also serve as a food source for pathogens, which can create a whole new set of problems. 

2. Fertilize Your Tree

To give your tree an extra dose of nutrients and promote its overall health, fertilize it after any injury.

1. Choose the best fertilizer based on an NPK value (nitrogen, phosphorus, potassium). Each tree will have different needs; some need more nitrogen, and others more potassium. Some fertilizers are specially labeled for certain species of trees, such as pines. Do your research before buying.

2. Determine the root zone by multiplying the distance from the trunk to the end of the longest branch, and multiplying that number by itself and then by 3.14. This will determine the root spread and how much fertilizer you need—you should plan on 2–4 pounds of fertilizer for every 1,000 square feet of root spread.

3. Apply the fertilizer to the entire root zone area. 

4. Irrigate soon after applying the fertilizer to wash any fertilizer from the leaves and help the nutrients penetrate through the soil.

3. Brace, Cable or Dress Problem Areas

More severe tree trunk damage likely requires cabling and bracing in order to save it. This method is best used on trees with weak trunks or those susceptible to further damage from high winds.

1. Hire a tree maintenance specialist to install stabilizing cables and brackets into the tree.

2. The tree specialist will tie and tighten the cables and brackets accordingly to ensure they are snug.

3. Keep the cable and bracket system in place to maintain the tree’s stability.

DIY vs. Hire a Pro

Unless a tree is only mildly damaged, you’ll want to call in a professional tree maintenance specialist to assess the injury and determine if a bridge graft is needed. A tree maintenance expert can evaluate the extent of the damage, recommend the best solution, and implement it right away. Some solutions, such as adding a brace and cable system, must be installed by professionals to ensure they’re implemented correctly.

Cost to Repair a Damaged Tree Trunk

Expect to spend between $250 to $2,500 to hire a local tree maintenance specialist. Some tree specialists may charge a consultation fee, but may waive that fee if you hire them. If you prefer to try DIYing the tree trunk repair, you’ll need to purchase supplies such as a hammer, chisel, and fertilizer. While the cost of these materials is typically less expensive than hiring a professional, it doesn’t guarantee lasting or accurate results.

Signs of Tree Bark Damage 

Tree bark damage may be tricky to spot unless you know what to look for. If you inspect your trees and find warning signs of damage to your tree, hire a tree specialist who can evaluate the best course of action to save or remove the tree. Check your trees regularly for the following signs of bark damage:

• Missing bark

• Decaying bark

• Holes in the bark

• Cracked or split wood

How to Prevent Bark Damage

Bark can be damaged by so many things, both natural and unnatural. Even so, there are some preventative measures you can take to avoid the worst.

1. If you live in an area with sneaky underground critters like gophers and rabbits, wrap your tree’s trunks with wire mesh.

2. Prevent nicks and scrapes from lawn equipment by planting ground-cover plants or placing mulch around the base of the tree in lieu of grass.

3. Noticing several holes in your tree’s bark? If woodpeckers are a concern, place bird netting around the tree.

4. Make sure to plant new trees in places where they will have enough room to grow properly without getting in the way of cars.

Why Is Tree Bark Important?

A tree’s bark is like its skin, providing a much-needed barrier from all sorts of hazards, such as extreme weather or other sorts of physical damage. The bark holds some of the tree’s connective tissue, which helps bring food and water to the tree and helps it to thrive. In addition, the bark prevents insects and diseases—including bacteria and fungi—from penetrating the tree, which can cause it to decay, ultimately weakening and killing the tree.

When a tree is wounded, the injury does not heal exactly as before. Instead, trees seal off the damaged area by forming a callus-like tissue around the wound's edges. New wood grows around the wound, creating a protective layer to prevent pests and diseases from getting into the newly formed tissue.