If you have an ash tree in Ellicott City, Columbia, or anywhere else in Howard County, this post is about your tree specifically. Emerald ash borer — a metallic-green beetle from Asia, first found in Maryland in 2003 — has effectively worked its way through the state's ash population. The practical reality for homeowners is blunt: an untreated ash in this county is either infested now or will be, and the ones already dead are on a clock that makes them more dangerous and more expensive every month.
You can see the scale of it on public land. Howard County's Department of Public Works has an ongoing program removing dead and dying ash trees along county roads, precisely because standing dead ash near a target is a liability. The same logic applies to the one in your back yard.
First: is it actually an ash?
Worth confirming before you worry. Ash trees have opposite branching — twigs and buds emerge directly across from each other rather than staggered. That alone eliminates most trees; in Maryland only ash, maple, dogwood, and horse chestnut share it. Ash leaves are compound, usually five to nine leaflets on a single stem. Mature bark forms a tight, regular diamond lattice. If your tree has alternate branching, you can stop reading and relax.
The signs, roughly in the order you'll notice them
Canopy dieback from the top down. This is almost always the first visible symptom. The upper third thins, then bare branches appear against the sky while the lower canopy still looks fine. By the time you notice it, the beetle has usually been in the tree for two to four years.
Woodpeckers going after the trunk. Heavy woodpecker work on an ash — especially patches where the outer bark has been flaked off to expose lighter wood underneath, sometimes called "blonding" — means birds are finding larvae. It's one of the most reliable early tells, and often shows up before you'd otherwise look twice at the tree.
D-shaped exit holes. About an eighth of an inch across, flat on one side. This is the emerging adult beetle's signature and is diagnostic — round holes are a different insect. You'll usually need to be close to the trunk to see them.
Epicormic sprouts. Shoots erupting from the trunk and root flare, below the dying section. The tree is attempting to grow new leaves anywhere it still can. It looks like vigor; it's distress.
Vertical bark splits, often with S-shaped larval galleries visible underneath if you peel back a flap. That serpentine tunneling is what kills the tree — the larvae sever the vascular tissue just under the bark, and the tree effectively starves.
The Maryland DNR maintains a photo guide if you want to compare against your own tree. Maryland Department of Agriculture asks residents to report infestations at 410-841-5920.
Treat or remove?
The honest split, and we'd rather tell you this than sell you a removal you don't need:
Under about 30% canopy loss — treatment is worth considering. Systemic insecticides applied as a soil drench or trunk injection are genuinely effective on trees caught early. The catch: it isn't a cure. You are committing to repeat treatment every one to two years for as long as you want the tree, because the pressure never goes away. For a large, healthy, well-placed shade tree that's often a good trade. For a mediocre ash in a back corner, it rarely is.
Over roughly 50% canopy loss — the vascular damage is done and treatment won't bring the canopy back. At that point you're deciding when to remove, not whether.
The economics are simple: treatment runs a few hundred dollars per application, indefinitely. Removal is a one-time cost. Do that math against how much you actually value the specific tree.
The six-month window that changes everything
This is the part most homeowners don't hear until it costs them money. Dead ash becomes dangerously brittle, fast. Living ash is a tough, flexible wood — it's what baseball bats are made from. Dead ash is the opposite: limbs snap without warning, and the structural wood a climber relies on stops being trustworthy.
Most reputable tree companies, ours included, will not put a climber in an ash that has been dead more than about six months. That isn't caution theater. It means the job that would have been a straightforward climbing removal now requires a bucket truck, or a crane if access is tight — and the price moves accordingly, sometimes by more than double.
So the sequence matters enormously. An ash removed while the canopy is thinning is a normal job at a normal price. The same tree two years later, fully dead and brittle over a driveway, is a specialty job. If you already know the tree is going to come down, waiting only costs you.
What removal actually looks like
For a standing dead ash near a house, driveway, or power line, the work is sectional — taken down in controlled pieces rather than felled whole, with limbs rigged and lowered rather than dropped. Access determines a lot of the cost: an ash in an open back yard with gate clearance is straightforward, while one wedged between a deck and a fence line is not.
The stump is a separate decision. Ash stumps don't resprout aggressively the way some species do, so there's no urgency beyond appearance and mowing — though it's cheaper to grind while the crew and equipment are already on site.
One local note: dead ash standing in the woods behind your property is not automatically your problem, but dead ash within falling distance of your house, your neighbor's house, or a shared fence is. If it's your neighbor's tree, the liability rules in Maryland hinge on whether the owner knew it was hazardous — and a dead ash is about as documentable a hazard as exists.
Permits
Removing a dead or hazardous tree on your own residential property in Howard County is generally straightforward, but the rules vary by property, and Columbia villages add a covenant layer on top of county requirements. See our Howard County permit guide and, if you're in Columbia, the village architectural approval process.
Not sure whether your ash is treatable or past saving? We'll look at it and tell you straight — call 410-826-9006 for a free written estimate anywhere in Howard County.