Oregon Revised Statutes Revenue and Taxation § 305.425

(1) All proceedings before the judge of the tax court shall be original, independent proceedings and shall be tried without a jury and de novo.

(2) If a statute provides for an appeal to or a review by the court of an order, act, omission or determination of the Department of Revenue, a board of property tax appeals or of any other administrative agency, the proceeding shall be an original proceeding in the nature of a suit in equity to set aside such order or determination or correct the act or omission. The time within which the statute provides that the proceeding shall be brought is a period of limitations and is not jurisdictional.

(3) All hearings and proceedings before the tax court judge shall be in accordance with the rules of practice and procedure promulgated by the court, which shall conform, as far as practical to the rules of equity practice and procedure in this state.