The Emerald Necklace Conservancy announces the availability of The 2011 Trees of Boston Calendar, featuring Erik Gehring’s beautiful photographs of trees of the Arnold Arboretum.  Erik generously donates a portion of sales to support the Conservancy’s work in the parks.  You may view and purchase the calendar ($12 for one, $33 for three, and $50 for five) on the Conservancy’s website, www.emeraldnecklace.org.