(h) For eligible timberlands held by the taxpayer for at least a 17-year period beginning on or after January 1, 2005 but less than an 18-year period beginning on or after January 1, 2005, 8/15 of the gain recognized on the sale of the eligible timberlands;

(i) For eligible timberlands held by the taxpayer for at least an 18-year period beginning on or after January 1, 2005 but less than a 19-year period beginning on or after January 1, 2005, 3/5 of the gain recognized on the sale of the eligible timberlands;

(j) For eligible timberlands held by the taxpayer for at least a 19-year period beginning on or after January 1, 2005 but less than a 20-year period beginning on or after January 1, 2005, 2/3 of the gain recognized on the sale of the eligible timberlands;

(k) For eligible timberlands held by the taxpayer for at least a 20-year period beginning on or after January 1, 2005 but less than a 21-year period beginning on or after January 1, 2005, 11/15 of the gain recognized on the sale of the eligible timberlands;

(l) For eligible timberlands held by the taxpayer for at least a 21-year period beginning on or after January 1, 2005 but less than a 22-year period beginning on or after January 1, 2005, 4/5 of the gain recognized on the sale of the eligible timberlands;

(m) For eligible timberlands held by the taxpayer for at least a 22-year period beginning on or after January 1, 2005 but less than a 23-year period beginning on or after January 1, 2005, 13/15 of the gain recognized on the sale of the eligible timberlands;