If any person's property is damaged by laying out, altering or discontinuing a county highway, the county commissioners shall estimate the amount, and in their return state the share of each separately. Damages shall be determined as if the land were taken for highway purposes under chapter 3. Damages shall be allowed to the owners of reversions and remainders and to tenants for life and for years in proportion to their interests in the estate taken. Said commissioners shall not order such damages to be paid, nor shall any right thereto accrue to the claimant, until the land over which the highway or alteration is located has been entered upon and possession taken for the purpose of construction or use.   [PL 1975, c. 711, §§ 2, 3 (AMD).]