On top of Grandfather Mountain, like many mountain peaks above 5000' in North Carolina, grows an "island" of Southern Appalachian spruce-fir forest. Though the forest was largely devastated during the 20th century by the introduction of the non-native balsam wooly adelgid, a remnant of this biome still exists on Grandfather Mountain. Many of these fir trees have been permanently bent by the high winds that often prevail from the west. In addition to fir trees, these "mountaintop island" biomes are a valuable and threatened habitat for many other flora and fauna suited to survival at higher elevation.