Minn. Stat. § 348.02: CLAIM AND PROOF.

The claimant shall file with the county auditor a plat giving the government subdivision, and the position of the trees thereon. If the number of trees be increased, supplemental plats shall be filed. The claimant shall show ownership of the land, and make oath to the planting and maintaining of the trees, as prescribed in section 348.01; and the proof shall be supported by the affidavit of at least two landowners residing in the same town, who have personal knowledge of the facts. Such proofs shall be filed with the county auditor between July 1 and July 15, of the year for which compensation is claimed.