There is a new report analyzing the value of protected open space in SE PA that should interest you. The study, commissioned by the GreenSpace Alliance and Delaware Valley Regional Planning, reports the following:

Approximately 300 square miles, or 14%, of the five-county region is protected open space. The study found that this area:

• Adds $16 billion to the value of southeastern Pennsylvania’s housing stock – an average property value increase of $10,000 per household;
• Saves local governments and taxpayers more than $132 million a year in costs associated with provision of environmental services such as drinking water filtration and flood control;
• Helps residents and businesses avoid nearly $800 million in direct and indirect medical costs as a result of recreation that takes place on protected open space;
• Generates more than $270 million in state and local tax revenue; and
• Supports nearly 7,000 jobs.

The entire report is available here.