Wash. Rev. Code § 37.08.220
The legislature of the state of Washington hereby consents to the acquisition by the United States by purchase or gift of such lands in the state of Washington as in the opinion of the government of the United States may be needed for the establishment, consolidation and extension of national forests in this state under the provisions of the act of congress approved March 1, 1911, and entitled: "An act to enable any state to cooperate with any other state or states or with the United States for the protection of the watersheds of navigable streams and to appoint a commission for the acquisition of lands for the purpose of conserving the navigability of navigable rivers," as amended: PROVIDED, The state of Washington shall retain a concurrent jurisdiction with the United States in and over lands so acquired so far that civil processes in all cases, and such criminal processes as may issue under the authority of the state of Washington against any person charged with the commission of any crime without or within said jurisdiction, may be executed thereon in like manner as if this consent had not been granted: PROVIDED FURTHER, That before any acquirement of lands be made under the provisions of this section, such acquisition shall be approved by the department of natural resources: AND FURTHER PROVIDED, That the state of Washington shall retain concurrent jurisdiction to tax persons and corporations and their property and transaction on such lands so acquired.
RCW 37.08.220
County may convey forestlands to United States: RCW 36.34.210.