Me. Rev. Stat. tit. 14, § 101

In actions for trespass on lands, the defendant may by answer disclaim all title to the land described, and allege that the trespass was involuntary, or by negligence or mistake, or in the prosecution of a legal right, and that before action brought the defendant tendered sufficient amends therefor or that the defendant brings money into court to satisfy the damages with costs to that time. If on trial the defendant establishes the truth of the defendant's allegations, the defendant recovers costs.