How Old are the Oldest Trees in D.C.?

“Dear PoPville,

This is kind of a random question, but does anyone have any idea what the oldest trees in DC are? I ask because there is a pretty massive tree in front of my house (see photo above), and it seems like it has been there longer than even this part of the neighborhood (Woodridge).”

Ed. Note: Off to Casey Trees I go, BRB.