(1) ACTION BY PURCHASER AT TAX OR JUDICIAL SALE. The purchaser at any sale of real estate for taxes or at judicial sale or by virtue of a power of sale in a mortgage, may sue to restrain the commission of waste during the period before the purchaser takes possession and may, in such action or by a subsequent action, recover damages against any person for any waste committed by such person on the premises after such sale. But no person lawfully entitled to the possession of any premises so sold shall be liable to any such action for doing any of the acts authorized in sub. (2).(2) NO WASTE. Any person entitled to the possession of lands sold under sub. (1) may, until the expiration of the time given by law for the person's possession, use and enjoy the same without being liable to an action of waste therefor, as follows: (a) The person may use and enjoy the premises sold in like manner and for the like purposes in and for which they were used and applied prior to such sale, doing no permanent injury to the freehold.(b) If the premises sold were buildings, fences or any other structures, the person may make necessary repairs thereto, but the person shall make no alterations in the form or structure thereof so as to impair or lessen their value.(c) The person may use and improve the land so sold in the ordinary course of husbandry or mining, and the person shall be entitled to any crop growing thereon at the expiration of the period of redemption.(d) The person may apply any wood or timber on such land to the necessary repairs of any fences, buildings or structures existing thereon at the time of such sale.(e) If the land sold is actually occupied by such person, the person may take the necessary firewood therefrom for the use of the person or the person's family.1973 c. 189; Sup. Ct. Order, 67 Wis. 2d 585, 767 (1975); Stats. 1975 s. 844.05; 1981 c. 314; 1993 a. 486. Waste may be defined as unreasonable conduct by an owner of a possessory estate that results in physical damage to real estate and substantial diminution in the value of estates in which others have an interest. Pleasure Time, Inc. v. Kuss, 78 Wis. 2d 373, 254 N.W.2d 463 (1973).