Why Are My Ash Trees Dying? A Guide to Emerald Ash Borer in Chisago City and the St. Croix Valley

If you live in Chisago City, Stillwater, Hudson, or the St. Croix Valley, you’ve likely noticed the “blonde” patches on Ash trees or entire rows of trees standing dead. The culprit is the Emerald Ash Borer (EAB)—an invasive beetle that has devastated the local canopy.

emerald ash borer

Will Parson/Chesapeake Bay Program/CC BY-NC 2.0

Emerald Ash Borer damage

CC BY-SA 2.0, USDA NRCS South Dakota

What is Emerald Ash Borer (EAB)?

The Emerald Ash Borer is a metallic-green beetle that lays eggs in the crevices of Ash tree bark.

Once the larvae hatch, they tunnel into the tree, eating the vascular tissue (the phloem and cambium) that transports water and nutrients.

EXPERT INSIGHTS
Watch: Precision Ash Tree Removal for Emerald Ash Borer in Chisago City

In this video, Chisago City tree service foreman Arthur explains the technical dismantling of a mature Ash tree in Chisago City, MN. This tree was heavily infested with Emerald Ash Borer in Chisago City, which had already begun destroying its vascular system, making the wood brittle and prone to failure.

To ensure maximum safety and minimal property impact, we utilized our NiftyLift aerial bucket, allowing our tree service crew to access the upper canopy without climbing the compromised structure. This “low-impact” approach is essential for Minnesota winters, where protecting the frozen turf and surrounding landscape is a top priority for homeowners.

Contact us for a free evaluation of your trees.

Top 3 Signs Your Ash Tree Has EAB

  1. Canopy Dieback: The leaves at the very top of the tree begin to thin and die first.

  2. Woodpecker Damage (“Blonding”): Woodpeckers love EAB larvae. If you see light-colored patches where birds have stripped the outer bark, the larvae are likely underneath.

  3. S-Shaped Galleries: If bark falls off, you will see serpentine patterns etched into the wood—the “signature” of a feeding larva.

Can an Ash Tree Be Saved?

If the tree has lost more than 30% of its canopy, removal is usually the only safe option. However, if the tree is still healthy, we offer trunk injections that can protect it for up to two years.

Why Professional Removal is Necessary

Ash trees killed by EAB become extremely brittle very quickly. This makes them dangerous for “DIY” removal. Our team uses specialized aerial equipment to safely remove these “dead-standing” hazards before they fall on property.

FAQ

In the Chisago Lakes area and St. Croix Valley, the most common signs are “canopy thinning” (leaves disappearing at the top), woodpecker blonding (light patches where birds strip bark to find larvae), and vertical bark splitting. If you peel back a small section of bark and see S-shaped serpentine galleries, your tree is confirmed to have EAB.

The Minnesota Department of Agriculture recommends conducting removals during the “Dormant Season,” which runs from October 1st to April 30th. Removing trees during this window prevents the spread of adult beetles, which are active and “flying” during the warmer months.

Because Chisago County is under EAB quarantine, it is illegal to move Ash wood out of the county. While you can keep the wood for use on your own property, we highly recommend professional disposal or on-site chipping to ensure no larvae survive to infect your neighbors’ trees.

Unlike other species, Ash trees become extremely brittle almost immediately after they die. The larvae destroy the tree’s ability to move water, causing the wood to “dry out” while still standing. This makes them unpredictable and dangerous to climb, which is why we use specialized aerial lifts like the NiftyLift for these removals.

If your tree still has more than 70% of its canopy intact, it may be a candidate for trunk injections. This professional-grade insecticide kills the larvae and protects the tree for up to two years. However, once a tree has lost 30% or more of its leaves, removal is usually the only safe and cost-effective option.

EEmerald Ash Borer Expertise You Can Trust: The NWI Tree Service Team

NWI Tree Service

The team at NWI Tree Service has been the St. Croix Valley’s trusted source for professional tree care and hazard mitigation since 2013. As local specialists serving Chisago City and the St. Croix Valley, we combine deep-rooted arborist knowledge with the specialized equipment needed to handle our region’s unique challenges.

Every Emerald Ash Borer (EAB) assessment and removal we perform is backed by years of observing how this invasive beetle impacts the structural integrity of trees in our local climate. Our expert tree service crews specialize in the technical, high-risk removal of brittle Ash trees, utilizing low-impact technology like our NiftyLift to ensure your property remains safe and undamaged. Our mission is to protect the safety and value of our communities’ landscapes through proactive health care and expert, precision removals.

RELATED POSTS

SHARE

Related Posts