Mont. Code Ann. § 70-16-210

If the occupants of adjoining lands build their respective portions of a partition fence and either of them at any time desires to let the land occupied by that person lie open, that person may, after having given to the occupants of the adjoining land at least 6 months' notice of the intention so to do, remove that person's proportion of the partition fence unless the adjoining occupant pays or tenders to that person the value of the fence. If the fence is removed without notice or after payment or tender of the value, the person removing the fence is liable to the person injured for all damages the injured person may sustain.