This test method covers the determination of the relative effectiveness of wood preservatives in round posts set in the ground in field plots. Two tests are described, one for small (3 to 5 in. (80 to 130 mm) in diameter) sapwood posts which is the preferred test if major interest lies in testing the preservative when fairly evenly distributed throughout the piece, and the second for large posts (7 to 10 in. (180 to 250 mm) in diameter) which is preferred when the preservative is tested under conditions of gradient retention and distribution normally encountered in commercial operations. The requirements for preparation of the material for testing and the test procedures appear as follows: The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units may be approximate. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.