Carmel's canopy and what's at risk
Carmel Urban Forestry publishes an approved species list (last revised 3/28/2024) whose "Undesirable Trees" section reads like a field guide to what fills older Hamilton County streets: silver maple (shallow roots, weak wood), Callery pear, pin oak, red maple and all Fraxinus for emerald ash borer. Approved large street trees run to swamp white oak, bur oak, chinkapin oak, hackberry, male-only ginkgo, thornless honeylocust, Kentucky coffeetree, baldcypress and London planetree; note Callery pear is discouraged locally but is not yet banned in Indiana — 312 IAC 18-3-25 currently lists 44 species without it.
What to look for
General decline, thin canopy, early autumn colour, sometimes mushrooms at the base.
Whether the tree can be saved
By the time the canopy shows it, the root system is already badly compromised. This is a stability question as much as a health one — a tree with rotten roots can look fine and still come over in a storm.