The legislature finds that it is necessary to give the several boards of library trustees in this state additional powers in order to effectuate the state's policy with regard to libraries as set forth in RCW 27.12.020. On and after March 27, 1975 the board of library trustees in any county of this state, in addition to any other powers and duties, is hereby authorized to provide library services to Indian tribes recognized as such by the federal government or to supplement any existing library services of such an Indian tribe. The power granted by this section shall extend beyond the geographic limits of the library district and the county or counties in which the district is located.