"Accreditation solidifies our commitment to the preservation of our natural and cultural landscape resources and provides the opportunity to tell the stories behind the magnificent trees found here," said Stephen Van Hoven, horticulture division chief.

To commemorate this achievement and celebrate Arbor Day, Arlington hosted a free guided walking tour of its grounds and a tree planting.

The peaceful and beautiful grounds of Arlington honor the service and sacrifice of the more than 400,000 active duty service members, veterans and their families who rest here. The Arboretum includes a blend of formal and informal landscapes, dotted with more than 8,600 trees comprised of more than 300 species, cultivar or variety. The collection includes trees that pre-date the establishment of the cemetery, estimated to be between 200 and 250 years old; two state champions; a substantial set of Memorial Trees; and trees that honor Medal of Honor recipients.

To commemorate the cemetery's 150th anniversary in 2014, the historic landscape was established as the Memorial Arboretum, serving as a living memorial to those who have sacrificed their lives for the nation and connecting visitors to the rich tapestry of the cemetery's living history and natural beauty.