Oregon Revised Statutes Property Rights and Transactions § 105.615

Unless otherwise agreed or provided in a granting document, a tenant in common of real property may acquire fee simple title to the real property by adverse possession as against all other cotenants if the tenant in common or the tenant in common's predecessor in interest has been in possession of the real property, exclusive of all other cotenants, for an uninterrupted period of 20 years or more and has paid all taxes assessed against such property while in possession. Notice of the exclusive possession need not be given to the other cotenants by the cotenant in possession.