But for locals, the sycamore tree held a profound presence — there, for as long as anyone could remember, for picnics, shade and quiet moments of reflection. In the weeks and months after it was felled, visitors wrote short poems dedicated to the tree. “I treasure memories of walking up that rough, steep path to see this open-armed wonder of a tree, lit by bright blue skies, a patchy shade for sandwiches and a home to so many creatures,” one person wrote in a visitor book at The Sill the day after the tree was felled. “You’ve always been there throughout our lives and before,” wrote another. Mr. Whinney, a woodworker who is studying regenerative design at Central Saint Martins at the University of the Arts London, incorporated some of the messages into the art installation.