(c)__For eligible timberlands held by the taxpayer for at least a 12-year period__beginning on or after January 1, 2005 but less than a 13-year period beginning on or after January 1, 2005, 1/5 of the gain recognized on the sale of the eligible timberlands;

(d)__For eligible timberlands held by the taxpayer for at least a 13-year period__beginning on or after January 1, 2005 but less than a 14-year period beginning on or after January 1, 2005, 4/15 of the gain recognized on the sale of the eligible timberlands;

(e)__For eligible timberlands held by the taxpayer for at least a 14-year period__beginning on or after January 1, 2005 but less than a 15-year period beginning on or after January 1, 2005, 1/3 of the gain recognized on the sale of the eligible timberlands;

(f)__For eligible timberlands held by the taxpayer for at least a 15-year period__beginning on or after January 1, 2005 but less than a 16-year period beginning on or after January 1, 2005, 2/5 of the gain recognized on the sale of the eligible timberlands;

(g)__For eligible timberlands held by the taxpayer for at least a 16-year period__beginning on or after January 1, 2005 but less than a 17-year period beginning on or after January 1, 2005, 7/15 of the gain recognized on the sale of the eligible timberlands;

(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;