Land bearing timber of more than ten years’ growth, such timber having a taxable value, may be classified as forest land as specified in section 12-96, and shall thereafter be taxed annually at the local rate, but not more than ten mills in any case, upon the true and actual value of the land and timber separately as established by the assessors at the time the classification was made. A revaluation of both land and timber separately shall be made by the assessors fifty years after the date of original classification, such revaluation to be subject to an annual tax at the local rate, but not more than ten mills, for another period of fifty years. At the end of this period, provided such classification has been continuously maintained, such land and timber shall, whenever necessary, be revalued separately by the assessors, and such new valuation shall be taxed annually thereafter at the local rate. Whenever a cutting is made on land classified under this section, except as specified in section 12-100, the material removed shall be subject to a graduated yield tax at the following rates on the value determined as provided in section 12-100: From one to ten years after the land has been classified the tax shall be two per cent of the yield; from eleven to twenty years after the land has been classified the tax shall be three per cent of the yield; from twenty-one to thirty years after the land has been classified the tax shall be four per cent of the yield; from thirty-one to forty years after the land has been classified the tax shall be five per cent of the yield; from forty-one to fifty years after the land has been classified the tax shall be six per cent of the yield; over fifty years after the land has been classified the tax shall be seven per cent of the yield. 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 section 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 section 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.