In Washington state we wrap growth boundaries around a 20 year supply of buildable urban land. This results in a spreadsheet approach to planning that is very quantifiable. Often times, conderation of urbanizing Ag lands is supported by the quantification of the economic benefits (capital investment, sales tax revenue, and other multipliers). I am searching for studies on the value of rural and ag lands. We have lots of great policy language on thew protetcion of rural character and ag lands, but I need numbers. Any advice?