The four largest islands are predominately vegetated with boreal forest. The trees growing on these islands are shallowly rooted with only about six inches of soil in most places. Many parts of the islands are exposed granite with lichens and reindeer moss growing in thick mats in places. Despite the difficulties of survival, balsam fir, white pine, red pine, white spruce, red maple, bigtooth aspen and paper birch make up the tree community. Cherry, Canada yew and other shrubs, grasses and wildflowers can also be found growing in the understory. The boreal forest is home to a number of warbler species as well as cedar waxwing, red breasted nuthatch, garter snakes, and small mammals such as the red bat, mice and voles.