 Once in the grove, the trail makes a meandering three mile (5 km) loop, with substantial use of boardwalks to protect the fragile forest floor.The reserve was initiated by a 9-acre (3.6 ha) donation from Robert Orr in 1945, with 765 acres (310 ha) donated since 1947 by the Save the Redwoods League.Between December 1996 and August 2000, the tallest tree in Montgomery Woods, named the Mendocino Tree, was the world's tallest known tree.