PA Clean and Green Tax Assessment:
"Clean and Green is a preferential tax assessment program, that bases property taxes on use values rather than fair market values. This ordinarily results in a tax savings for landowners. The Pennsylvania General Assembly enacted the program in 1974 as a tool to encourage protection of the Commonwealth's valuable farmland, forestland and open spaces...
WHAT ARE THE ELIGIBILITY REQUIREMENTS? A property must be ten acres in size, and in Agricultural Use, Agricultural Reserve, or Forest Reserve. Agricultural Use applications may be less than 10 acres in size if the property is capable of generating at least $2,000 annually in farm income."
The deadline to file for an agricultural classification is June 1st.