When, in the judgment of the Commissioner of Forestry, he deems it necessary for general forest protection that causes or agencies injurious to trees and forests, other than fire, be investigated, reported upon, or abated, he is hereby authorized to assign to the Bureau of Forest Protection persons competent for such work. The salaries of such persons, so assigned, shall be fixed by the Commissioner of Forestry, and shall in no case exceed the ordinary and usual amount paid for such services. Salaries and expenses shall be paid out of the general forest protection appropriation.
32 P.S. § 421