Oregon Revised Statutes Revenue and Taxation § 307.010

(a) “Land” means land in its natural state. For purposes of assessment of property subject to assessment at assessed value under ORS 308.146, land includes any site development made to the land. As used in this paragraph, “site development” includes fill, grading, leveling, underground utilities, underground utility connections and any other elements identified by rule of the Department of Revenue.

(b) “Real property” includes:

(a) Any of the timber standing upon the land, with the right to enter upon the ground and remove the timber, the ownership of the standing timber so reserved or conveyed is an interest in real property.

(b) The right to enter upon and use any of the surface ground necessary for the purpose of exploring, prospecting for, developing or otherwise extracting any gold, silver, iron, copper, lead, coal, petroleum, gases, oils or any other metals, minerals or mineral deposits in or upon the land, such right is an interest in real property.