## Facts

- Isle Royale Mining Company and John and Michael Hertin owned adjoining timbered tracts in Michigan.
- During the winter of 1873–1874, the Hertins, acting under a good-faith boundary mistake, entered the mining company’s land rather than their own.
- The Hertins cut cordwood from the mining company’s timber and hauled and piled it on the bank of Portage Lake.
- The following spring, the mining company took possession of the piled wood and used or disposed of it.
- Trial evidence valued the wood as piled at $2.87½ per cord and the Hertins’ cutting-and-piling labor at $1.87½ per cord.
- It was not clearly shown that the mining company knew of the cutting and hauling while it was occurring.

## Issues

1. Whether mistaken timber cutters who trespassed on another’s land acquired a sufficient property interest in the severed wood to maintain trover against the landowner who later took it.
2. Whether the landowner’s later appropriation of the cut and piled wood created an implied obligation in assumpsit to pay the trespassers for their labor (waiver of tort / implied contract).

## Decision

- The Michigan Supreme Court reversed the circuit court’s judgment for the Hertins, awarded costs to the mining company, and ordered a new trial.
- The court held that the Hertins, as trespassers notwithstanding their mistake, acquired no property right in the wood that would support trover.
- The court held that the mining company’s later taking and use of the wood did not, on these facts, imply a promise to pay the Hertins for their labor.
- The court rejected applying accession principles because the timber was only cut and piled, with no substantial transformation making the product’s chief value the improver’s labor.

## Legal Principles

- Trover requires the plaintiff to have general or special property in the chattel, or lawful possession; a trespasser who wrongfully severs timber from another’s land lacks that interest as against the owner.
- Good-faith mistake about a boundary does not negate trespass and does not create affirmative rights in the trespasser against the true owner.
- Accession may shift title to an improver only when the change is sufficiently substantial and the resulting product’s value is chiefly attributable to the improver’s labor; mere severance and piling of wood is insufficient.
- An implied promise to pay for benefits is not inferred where the benefit was conferred through trespass and without the owner’s request or clear, contemporaneous knowledge and acceptance.

## Conclusion

The court ruled that mistaken woodcutters who trespassed and merely cut and piled timber could not recover from the landowner in trover or assumpsit after the landowner appropriated the wood, because the trespass created no compensable property interest and the improvement was too slight to trigger accession or implied-contract liability.


Isle Royale Mining Co. v. Hertin, 37 Mich. 332 (Mich. 1877)