Nothing in this chapter extends to house lots, the contents of which do not exceed half an acre; but if the owner of such lot improves it, the owner of the adjacent land shall make and maintain 1/2 of the fence between them whether that owner of adjacent land improves or not; nor does this chapter make void any written agreement respecting partition fences.   [PL 1987, c. 737, Pt. A, §2 (NEW); PL 1987, c. 737, Pt. C, §106 (NEW); PL 1989, c. 6 (AMD); PL 1989, c. 9, §2 (AMD); PL 1989, c. 104, Pt. C, §§8, 10 (AMD).]