DC's Casey Trees, Arlington County, VA government recognize notable trees in metro area; Washington, DC

Noble Honor Takes Root - washingtonpost.com:
The program rewards three categories: Big Trees, Witness Trees (of historic significance), and My Tree (of personal significance). Currently the Big Trees designation includes one national champion, a Jujube (Ziziphus jujube) located on the grounds of the U.S. Capitol. Its trunk has a 93-inch circumference. The 61-foot tall tree also has a spread of 51 feet.
All winners of the Trees of Note designation will be included on the Casey Trees online map. 'The [geocaching] course will change biannualy to feature different or new trees, different neighborhoods and seasonal changes,' Powell said. 'We hope the geocaching element will introduce individuals to urban forestry and the importance of trees in city living and encourage individuals to see the District as not just a brick and mortar city.'