Maple Tree Problems in MA

Maples are everywhere in Massachusetts. Sugar maples lining Main Street, red maples in the backyard, Norway maples that were planted in every subdivision from the 1950s through the 1980s. They provide the fall foliage that draws tourists to New England every October. But maples also have more than their share of problems, and some of those problems are species-specific issues that confuse homeowners who expect all maples to behave the same way.

I am Keith McDonald, owner of McDonald Tree Service in Billerica, MA. We have been diagnosing and treating maple problems across Middlesex County since 1995. Here are the issues we see most often.

The Norway Maple Problem

Let us start with the elephant in the room. Norway maple (Acer platanoides) was the most commonly planted street and yard tree in Massachusetts from the 1950s through the 1980s. It is tough, shade-tolerant, fast-growing, and it looked great on paper. The problem is that Norway maple is now classified as an invasive species in Massachusetts.

Why Norway maples are a problem:

• Dense shade and shallow root systems that kill lawn and understory plants. Nothing grows under a Norway maple.
• Prolific seed production. Norway maples spread into forests and outcompete native species.
• Aggressive surface roots that crack driveways, heave sidewalks, and invade sewer lines
• Shallow root systems that are vulnerable to windthrow
• They are host to a variety of diseases including verticillium wilt

In towns like Woburn, Burlington, Winchester, and Lexington, Norway maples make up a significant percentage of the urban tree canopy. Many of these trees are now 50 to 70 years old and reaching the end of their useful life. If you have a Norway maple that is causing problems, removal and replacement with a native species is often the best long-term decision.

Tar Spot (Rhytisma acerinum)

If your maple leaves develop raised black spots that look like someone dripped tar on them, that is tar spot fungus. It is one of the most common questions we get every summer. The good news: tar spot is almost entirely cosmetic. It does not significantly harm the tree.

What you need to know:

• Tar spot appears in mid to late summer as black, raised spots on leaves
• It is most common on Norway maples and silver maples
• The fungus overwinters in fallen leaves, so raking and disposing of infected leaves in fall reduces next year's infection
• No fungicide treatment is necessary or recommended for residential trees
• The tree will leaf out normally next spring

We see tar spot every year across our entire service area. Homeowners in Chelmsford and Tewksbury call about it regularly. The answer is always the same: rake the leaves, do not worry about the tree.

Verticillium Wilt

Unlike tar spot, verticillium wilt is serious. This soil-borne fungus (Verticillium dahliae) infects through the roots and clogs the tree's vascular system, blocking water transport. Symptoms include wilting and browning of leaves on one side of the tree or individual branches, often in mid-summer when the tree should be in full leaf.

Signs of verticillium wilt:

• Sudden wilting of leaves on one branch or one side of the canopy during summer
• Brown or olive-green streaking in the sapwood when you cut a dying branch (peel the bark and look at the wood)
• Progressive dieback over one to several years
• Small, sparse leaves on affected branches

Norway maples and sugar maples are most susceptible. There is no chemical cure for verticillium wilt. Management involves pruning out dead branches, watering and fertilizing to support the tree's ability to compartmentalize the fungus, and monitoring the progression. Some trees wall off the infection and survive for decades. Others decline rapidly and need removal within a few years.

Girdling Roots

Girdling roots are roots that grow around the trunk instead of outward, gradually strangling the tree by constricting the flow of water and nutrients. This is extremely common in maples, especially Norway maples and red maples that were container-grown before planting.

How to spot girdling roots:

• The trunk enters the ground like a telephone pole with no visible root flare. A healthy tree should have a visible flare where the trunk meets the roots.
• One side of the trunk appears flattened or indented at the soil line
• Canopy dieback on one side while the other side looks healthy
• The tree leans slightly and does not seem as firmly rooted as it should

If caught early, girdling roots can be cut to relieve the pressure. This requires careful excavation around the base to expose the root flare and identify which roots are circling. It is not a DIY job because cutting the wrong root can destabilize the tree. We do girdling root corrections on maples throughout Bedford, Concord, Acton, and Carlisle.

Leaf Scorch

Leaf scorch shows up as brown, crispy edges on maple leaves, usually in July and August. It is caused by the tree losing water through the leaves faster than the roots can replace it. This is a symptom, not a disease. Common causes include:

• Drought stress (the most common cause)
• Root damage from construction, compaction, or grade changes
• Road salt accumulation in the soil
• Restricted root space (trees planted too close to foundations or in small cutouts)

Sugar maples are especially prone to leaf scorch because they prefer cool, moist, well-drained soils. The sandy, dry soils in parts of Tewksbury and Wilmington stress sugar maples badly during dry summers. Read our summer watering guide for tips on keeping maples hydrated during drought.

Anthracnose

Maple anthracnose is a fungal disease that causes brown spots, curling, and premature leaf drop in cool, wet springs. Sugar maples and silver maples are most affected. Like tar spot, anthracnose looks worse than it is. The tree re-leafs in June and the new growth is usually healthy. No treatment is needed for established trees.

When a Maple Needs to Come Down

Maples are not the longest-lived trees. A Norway maple that was planted in 1965 is now over 60 years old and may be reaching the end of its safe, functional lifespan. Signs that a maple needs removal include:

• More than 50 percent canopy dieback
• Large trunk cavities or mushrooms growing from the base
• Severe girdling roots that cannot be corrected
• Surface roots causing structural damage to your home, driveway, or sewer lines
• Advanced verticillium wilt with progressive, rapid decline

For a complete guide on recognizing these warning signs, read our when to remove a tree article. For cost information, see our tree removal cost guide.

Get Your Maple Assessed

If your maple has any of the problems described above, or if you are not sure what is going on with it, call McDonald Tree Service at (978) 375-2272 for a free assessment. We will identify the species, diagnose the issue, and give you honest recommendations. We serve Billerica, Lowell, Dracut, Westford, Andover, Waltham, Lincoln, and all 18 towns in our Middlesex County service area.