This is a split in the wood itself, not just the bark, running from the outside toward the center. For the tree it means the outer wood is now open to air and water, and it will respond by walling the injury off and growing over it. Most trees live with a frost crack indefinitely and a healthy one closes it and carries on. The lasting significance is that the crack is a permanent line of weakness and a doorway for decay, so a trunk with one is a trunk you monitor rather than a trunk you fix. In Plainfield — Saratoga, Sugar Grove Farms and Blackthorne included, that's normally a tree trimming job at $250–$1,400. Not urgent.
Why this comes up in Plainfield
Duke Energy Indiana serves the majority of Plainfield, with Hendricks Power Cooperative and AES Indiana covering the rest. Duke Energy Indiana is the direct successor to Public Service Indiana, which built its headquarters in Plainfield. As an investor-owned utility Duke is bound by the IURC's tree-trimming rules (170 IAC 4-9): two weeks' notice, no removing more than 25% of a tree and no topping without the customer's permission, no trimming outside the easement without consent, and debris cleared within three days. Hendricks Power, as a cooperative, is not covered by those rules.
Plainfield's canopy
The most age-mixed canopy of the three: a genuine 1950s ring plus the pre-1900 Quaker core along Main Street (US 40) carries 60-to-90-year-old shade trees over the street, while Saratoga, Sugar Grove Farms and Legacy Farms hold 10-to-25-year-old planted stock, and the White Lick Creek bluffs hold the town's only real remnant woodland. Ash is gone here as everywhere in Indiana.
Hendricks County rules
Plainfield does not require a permit to remove a tree on private property, and its nuisance chapter goes out of its way to say so: Chapter 92's definition of "weeds and rank vegetation" excludes trees, bushes and shrubs planted or cultivated by the landowner. Trees are otherwise regulated only through development review in the Zoning Ordinance — required-yard and bufferyard landscaping scored by Plant Unit Value, an optional "Tree Save Area" credit for preserving existing stands, a ban on DNR-listed invasive plants as landscaping, and an Airspace Overlay District tied to Indianapolis International Airport that caps how tall a tree may be allowed to grow. None of these provisions could be verified against the current ordinance text — confirm section citations with the Planning Department.
The tree lawn in Plainfield
The strip between sidewalk and street is public right-of-way, but Plainfield has no municipal urban-forestry program of the kind neighboring Avon runs, and street-tree requirements appear only through development review rather than a standalone tree chapter — confirm with the Town Engineer before right-of-way work. What the town does control is obstruction: under Chapter 93 the Street Department may remove obstructions in the street without notice, and the Town Engineer administers the access-permit process for work affecting the right-of-way.