On planting memorial trees in Ireland: “It’s remembering a life, or an event in a life, that’s the idea,” says Mary Walsh, head guide at Muckross House, where donated trees are easily accessible to visitors. “We get them for births, marriages, but often it’s the memory of a life that’s being acknowledged.”

Walsh says the trees draw a surprising number of Irish Americans. “We get some out of the blue, they want to see the trees.”