The case for locally produced and consumed food will once again be discussed next Tuesday at a Museum of the City of New York forum that includes Blue Hill chef/owner Dan Barber and Greenmarket director Michael Hurwitz. Another speaker is Ian Marvy of Red Hook’s Added Value, whose farm will be just one of many volunteer sites comprising tomorrow's massive Earth Day initiative called the Green Apple Festival. The forum, an affordable $12, will be moderated by Gabrielle Langholtz, editor-in-chief of Edible Manhattan and Edible Brooklyn (the new Brooklyn issue features a behind the scenes look at Williamsburg biscuit lair Egg, and a tour of Brooklyn’s many tortillerias). Looking ahead, one more tidbit of locavore news— New Amsterdam Market announced today that June 28 will be the date of the first Monthly Market for 2009; details, including a location, are forthcoming.