Every Monday: Niaulani Nature Walk.  A free, guided rain forest tour in Volcano. This one-hour nature walk travels through a lush portion of an old-growth Hawaiian rain forest on an easy, 1/7-mile loop trail. The walk introduces visitors to the native plants and birds of Volcano. Guides focus on the biological, ecological, and geological features of the area, and the cultural usages of flora and fauna by native Hawaiians. Volcano Art Center’s Niaulani Campus, 19-4074 Old Volcano Rd., Volcano Village.…