Land fully stocked with forest trees not more than ten years old, except scattered older trees the value of which for timber does not increase the assessed value of the property, land incompletely or partially stocked with forest trees not more than ten years old, when planted with a sufficient number of additional trees to assure a spacing of approximately eight by eight feet over the entire area, and open land planted with forest trees not less than seven hundred to the acre, provided in each case the trees planted shall be ash, chestnut, maple, oak, tulip, white pine, red pine, Scotch pine, European larch or Norway spruce, or any other kinds of trees approved by the State Forester, and provided the State Forester shall approve the manner in which the trees are planted, may be classified as forest land as specified in § 12-96, and shall thereafter be taxed annually at the local rate, but not more than ten mills in any case, on a valuation of the land alone established and reestablished by the assessors of the town as provided in § 12-97. Whenever a cutting has been made, except as specified in § 12-100, a yield tax of ten per cent shall be levied on the value of the material removed, such value to be determined as provided in § 12-100. Whenever a timber crop has been removed, either in one or several cuttings, and the land reforested, either naturally or by planting, such land may be reclassified upon application by the owner, or the existing classification may be continued and tax collected on the established valuation as hereinbefore provided for the balance of the uncompleted valuation period. If the existing classification is continued, a revaluation shall be made at the end of such uncompleted period and taxes thereafter assessed as hereinbefore provided. Any owner of land classified under this section may, on or after October 1, 1972, but prior to October 1, 1973, and on or after July 13, 2011, convert to the provisions of § 12-107d without penalty, including, but not limited to, any penalty for the value of any standing timber, provided a sale or donation of such land to a nonprofit land preservation organization or the sale or donation of a permanent conservation easement upon such land precedes such conversion. On and after the last day of the calendar year that represents the fiftieth anniversary of the classification of such owner’s land under this section, any owner who elects to continue with such classification shall have an annual tax due that shall not exceed the annual tax due for a similarly situated landowner under the provisions of § 12-107d. Any owner who elects to no longer participate in such classification shall be subject to any applicable penalty as provided in this chapter. Any such owner desiring such conversion shall notify the board of assessors of the town in which the land is located by registered mail. Nothing in this section shall be construed to affect any other agreement between such owner and the town in which the land is located.