Why Are The Branches on My Maple Tree Dying?

Prized for their beautiful foliage, maple trees grow into towering beauties over the decades. That’s why it’s so upsetting when you notice that some of the branches have started dying off. This problem is common enough that it has a name: maple decline. If you find yourself asking why are branches on my maple tree dying?, our guide breaks down the common causes and the next steps to take to keep your maple tree healthy. 

Insects

When insects attack maple trees, they tend to coalesce in particular spots, which can lead to die-off in those areas, branch by branch. Common culprits include:

• Aphids: Aphids like the very noticeable wooly alder aphid may choose maple trees as a feast. As they suck out sap from vulnerable stems, those stems can die off over time. 

• Ambrosia beetles: Hailing from Asia, these beetles target young maple trees and bore into the bark to reach the tender wood within. At that point, a fungus hitchhiking on the beetles takes over, leading to branch death and other problems. Other borers act much the same way, including shoot borers and petiole borers.

Fortunately, bugs rarely threaten the life of a maple tree. But because they can cause unsightly damage in high numbers, it’s important to treat an infestation if you notice it. Youcan try natural remedies or contact a local tree maintenance professional for advice.

Diseases

Many different diseases can attack a maple tree and cause branches to die, and they’re not always easy to spot. Common maple diseases include:

• Anthracnose: This common fungal disease can attack many different parts of a maple tree, primarily focusing on foliage but also infecting new shoots and twigs, killing them off over time.

• Leaf or tar spots: These fungi infect leaves, and in severe cases they can cause early leaf drop that can make it look like branches are dying.

• Wilts: Wilts like Verticillium wilt are fungi that get their name from the way they make tree leaves wilt and die off. They can be dangerous because they infect the inner tree structure (usually causing brown streaks inside the wood) and can kill off entire parts of a maple.

• Cankers: Cankers are a type of fungal infection that can form noticeable lesions on bark, but the damage can go well below the surface. Many types of cankers, including branch cankers, are known to kill maple branches.

• Sapwood rot: Sapwood rots are similar to wilts but attack damaged parts of a tree and usually have visible shelf fungi markings.

• Bacterial leaf scorch/leaf burn: This is caused by a fast-spreading bacteria that devours leaves. It’s a particular problem for maple trees. While the tree limbs themselves are usually untouched, if the leaf scorch spreads enough, the maple loses most of its leaves early and becomes more vulnerable to other attacks. Notably, fungicides don’t work against bacterial infections like this.  

If you catch diseases early, the prognosis for the maple tree is usually good. You should do some serious, targeted pruning to get rid of infected growth and applya recommended fungicide. If you have multiple maple trees, conduct thorough inspections to make sure the disease doesn’t spread in the coming months. 

Environmental Stressors

Trees usually die slowly, so environmental problems can go unnoticed until branches start dying. One of the most common examples is drought or lack of water, which slowly dries out the tree until visible effects start showing. In these harsh conditions, a maple tree will usually start dying from the outside, so the newest growth and top of the canopy will show dead branches first. 

Excessive heat may cause scorched leaves, and if one side of the maple tree bears the brunt of the hot sun, its leaves may die off.

Sudden frosts can also damage a maple’s leaves and branches, especially if the tree is in a shady area. But although maple trees are particularly vulnerable to frost, any damaged twigs and branches typically grow back in time.

Root Damage

Photo: Deirdre Malfatto / Stocksy / Adobe Stock

Root damage is an insidious foe, causing hidden problems that can kill a tree years later. Landscaping, leveling nearby ground, or running heavy equipment over the ground can crush or choke roots, a phenomenon called soil compaction. Sometimes roots are even cut directly to make room for sidewalks, driveways, or patios. While maple trees can survive with some of their roots destroyed, the outlook isn’t good if too many roots are ruined.

Usually, the damage begins to show on the side that experienced the most root damage. Dying branches are a common sign, as trees can no longer draw in enough water and nutrients from the soil. Unfortunately, by the time these signs appear, there’s not much homeowners can do. Your best bet is prevention; aerating the soil near a maple tree can help prevent or reduce soil compaction.

Ice Melt

Rock salt and ice melt that’s used to keep paths or sidewalks safe during winter can significantly harm maple trees.

While maple trees may be hibernating during these times, the chemicals from these treatments run off into the soil and gather there. In large amounts, salt, magnesium and other common ingredients of ice melts can poison maple trees, stunting growth and eventually killing them. Some of these ingredients are even used as herbicides to kill trees professionally. Take great care when using ice melt near maple trees.

Girdling Roots

A girdling root is a large root that, instead of growing away from the tree, wraps around the base of the trunk instead. As the root grows, it slowly cuts off the flow of sap and nutrients to the crown of the tree, literally choking it. This happens slowly over years, and one side of the tree is often affected first, leading to dying branches.

Girdling roots often appear with some of the problems mentioned above, like soil compaction. They’re more likely if a maple tree is grown inside a container as a sapling for too long before being transplanted. Once a girdling root has been identified, remove it carefully to help save the tree. If the root is large or has grafted into the trunk already, you may need professional help. 

The Cost to Hire an Arborist

If you have a beloved maple with dying branches, an arborist near you can diagnose and treat the problem. Hiring a tree professional greatly increases the odds that your maple tree will survive and thrive. A tree inspection costs anywherefrom $150 to over $500.