I recently received an e-mail from a friend of my teenage daughter asking me to join her Facebook group to Save Gulf Branch Nature Center.  As a part of its budget cuts, Arlington County has proposed to close the center on July 1st.   The internet and social networking have allowed word to spread much more rapidly than it would have in the old days.  The Facebook group now has over 2800 members and the community has rallied around and set up a website where residents can sign a petition and make their voice heard in support of keeping this valuable resource.   While Arlington is becoming an increasingly urban community, we need to hold on to our parks, nature centers and green space.  A public hearing will be held at the courthouse March 24th and 25th.