Mo. Rev. Stat. § 537.350
If any person shall voluntarily throw down or open any doors, bars, gates or fences, and leave the same open or down, other than those that lead into his own enclosure, or shall voluntarily throw down, open or remove any partition fence, without giving six months' written notice to the person owning the adjoining fields, if they are cultivated lands, he shall pay to the party injured the sum of five dollars, and double the amount of damages he shall sustain by reason of such doors, bars, gates and fences having been thrown down or opened, with costs; provided, that this section shall not be construed to apply to fences erected across any watercourse in this state which carries sufficient water to move logs for lumbering purposes, of ten inches or more in diameter, and railroad crossties and piling; provided further, that any corporation, company or individual driving such logs, crossties or piling, or having placed the same in any such stream with the intent to drive or float the same, shall be liable for the actual damages which may result therefrom to any owner of land bordering on any such stream; but this section shall not be construed to include a fence erected across any such stream and not enclosing a farm or plantation, nor where, in any case, it is apparent that such fence was erected across such stream for the mere purpose of hindering the free passage of such logs, crossties or piling, or for the purpose of extorting money from the corporation, company or individual engaged in driving such logs, crossties or piling.
§ 537.350, RSMo
RSMo 1939 § 3682