Oregon Revised Statutes Procedure in Criminal Matters Generally § 136.310

All questions of law, including the admissibility of testimony, the facts preliminary to such admission and the construction of statutes and other writings and other rules of evidence shall be decided by the court. All discussions of law shall be addressed to it. Whenever the knowledge of the court is by statute made evidence of a fact, the court shall declare such knowledge to the jury, which is bound to accept it as conclusive, except as provided in ORS 40.085.