A terrific post, Mapping the 16th century garden, at The Gardens Trust's blog, pointed out the trees on the 1588 map of Luca in Braun and Hogenberg's Civitates Orbis Terrarum. Trees planted along the ramparts of a walled city—like a boulevard! Characters could stroll in peacetime. Could soldiers take cover during hand-to-hand fighting if the wall were overtopped by an invading army? For historical fiction, further investigation is called for; for fantasy, imagination. Meanwhile, a little moment of research rapture.