Volunteers stitch knit tree sweaters onto trees, adding color to the birches outside the Anchorage Museum on Friday, Feb. 6, 2015. Anchorage Guerrilla Knitters, led by Barbara Brown, knitted rectangles to attach to trees as public art during the First Friday event. More than 150 pieces were collected. "We're going to run out of trees before we run out of sweaters!" she said. Brown saw the knit graffiti art, known as yarn bombing or yarn storming, in Berlin and thought it could be done here. "Look how colorful the trees are!" marveled volunteer Terri Agee. "I can't imagine anything more fun than this!" added Gail Somerville.