The trustees may issue subpoenas to compel the attendance of witnesses before the trustees, or any member thereof, in the same manner as any court in this state. Whenever the testimony of any witness upon any matter pending before them is material, the trustees shall cause the attendance of the witnesses before the trustees, or a member of the trustees, to testify concerning the matter, and the trustees may make a reasonable allowance for this purpose not exceeding the fees of witnesses in civil cases. The allowance shall be paid for out of the appropriation for the expenses of the trustees, but in no instance shall an allowance be made in favor of a witness who appears in behalf of a claimant. The provisions of this section shall not apply to proceedings conducted in accordance with Chapter 5 (commencing with Section 11500) of Part 1 of Division 3 of Title 2 of the Government Code.