72 Pa. Stat. § 5583
In consideration of the public benefit to be derived from the planting and cultivation of forest or timber trees, the owner or owners of any land or lands in this commonwealth who shall plant the same with forest or timber trees, in number not less than three hundred to the acre, shall have a rebate in his or her or its taxes, to the amount of eighty per centum thereof, thereon, for a period of thirty-five years: Provided, That such rebate shall not amount to more than forty-five cents per acre; said period of exemption to be counted from the time the said land or lands shall have been planted with forest or timber trees, as aforesaid; or from the time it may have been necessary to replant the same, as aforesaid, by reason of destruction from fire; and the rebate herein provided for shall be calculated and allowed by the tax collector.
72 P.S. § 5583