Landscape architect David Valbracht turned to botanical illustration to develop a better method for identifying trees. A guest researcher at the Arboretum, David gathers plant samples from his studies in the collections and arranges them in his studio as they grew in life. These “tree portraits” emphasize drawing as a method to develop observation and identification skills, and at the same allow for personal expression. Now through June 9 at the Arnold Arboretum Hunnewell Building lecture hall at 125 Arborway is his exhibition Learning from Leaves.  The exhibition  centerpiece is a thirty-foot mural illustrating over 100 species of trees, grouped according to the Arboretum’s landscape plan. Valbracht studied landscape architecture at Harvard University, botanical art at the Wellesley College Botanical Garden, and is currently attending the Academy of Realist Art, Boston.  He and Maggie Redfern, Visitor Education Assistant, will lead a guided tour of the landscape on Sunday, May 19, beginning at 2 pm.  The activity is free, but in case of inclement weather, call 617-384-5209.