(DC) (Casey Trees) Join us and nature book author Melanie Choukas-Bradley for a three-hour tree walk along scenic Rock Creek and through the upland woods of the Western Ridge Trail. Melanie will show you how to identify American hornbeam, American elm, river birch, American sycamore, boxelder, black walnut and other stalwarts of the floodplain forest. She’ll then lead us into the upland woods where several species of oak, including DC’s official tree, the scarlet oak and a large spreading post oak, mockernut and pignut hickories, American beeches, and sugar and red maples flourish.