There is no clean checklist that says a tree must go — it is almost always a judgment call balancing risk, cost, and how much of the tree is salvageable. This guide walks through the warning signs that usually mean removal is the right answer, the gray-area cases where pruning or cabling can save a tree, and what a pro looks for before recommending the chainsaw.
For homeowners across DuPage, Kane, Cook, Lake, Will, and McHenry counties, the answer often turns on emerald ash borer damage, oak wilt, or storm splits — three problems we see more of than most regions.
These are the situations where a certified arborist will almost always recommend removal rather than try to save the tree.
Plenty of trees look worse than they are. Before assuming removal, check whether any of these apply:

Cabling, crown reduction, or selective pruning can extend the life of a marginal tree by a decade or more — and cost a fraction of removal plus replacement.
A few situations come up here that change the calculus:
EAB has already destroyed most untreated ash in the region. An ash with thinning canopy, woodpecker damage, and S-shaped tunnels under the bark is essentially a dead tree on a delay. Untreated infested ash should come down before they fall on their own — they get brittle fast.
A red oak that wilts and drops leaves rapidly in summer almost always has oak wilt. Removal is usually necessary to protect adjacent oaks, since the fungus can spread through interconnected root systems.
A tree that has lost more than about a third of its canopy in one event is structurally compromised. Sudden spring storms and lake-effect winds in the Chicago suburbs frequently cause this.
A reasonable arborist walks around the tree slowly, looks up, and looks down. They check:

A free estimate that walks past your tree without looking up is not really an estimate — it is a price.
A small dead ornamental tree in an open yard is a reasonable do-it-yourself project for someone with a chainsaw and the right protective gear. Anything else — large limbs, leaning trees, anything near power lines, anything close to a building — is a job for an insured professional with the right rigging.
The biggest hidden risk in DIY removal is property damage and the absence of insurance to cover it. A licensed crew carries general liability and workers compensation; you do not.
Scratch a small spot of bark on a young branch with your fingernail. Green underneath means alive; brown and dry means dead. Check several branches around the tree — partial die-back is different from a fully dead tree.
Usually no. Most homeowner policies cover damage caused by trees that fall, not preventative removal. There are exceptions for trees the insurer flags as hazards during inspection, but it is uncommon.
It depends mostly on size, location, and access. Small ornamental trees in open yards can run a few hundred dollars; large oaks near buildings or power lines can run several thousand. Get a free estimate before assuming.
If the canopy is more than half alive and the trunk is sound, often yes — that is called crown cleaning. If most of the canopy is dead or the trunk has serious decay, removal is usually safer and more economical long-term.
If you are not sure whether your tree needs to come down, JDS Tree Service has been making that call across the western Chicago suburbs for over 14 years and is fully licensed and insured.