When should an ash (green and white ash) be pruned?

Greenfield was not one of the 23 communities in the Indiana DNR street tree sample, so there is no published species breakdown — the honest picture is a two-tier canopy: mature shade trees dating to the historic district's roughly 1880-1947 build-out over those streets and Riley Park, versus small suburban stock in the newer additions. Statewide, Indiana street tree populations run about 18% silver maple and 34% maple overall; Callery pear is common in 1990s-2000s plantings and as of 2026 is still legal to sell in Indiana, with the amendment that would add it to the Terrestrial Plant Rule pending since 2021 — re-check IDNR before advising a customer. That context matters for ash (green and white ash): emerald ash borer has been confirmed in all 92 indiana counties since 2017, so the question on a central indiana ash is almost never whether to save it — the untreated ones are already dead or dying and only trees on an active systemic treatment program are still viable. Removing an ash (green and white ash) around Greenfield runs roughly $400–$1,900, and in Greenfield Residential Historic District, Brandywine Village and Fieldstone access is usually what decides where in that range you land.