The Ahklun Mountains are dominated by alpine tundra, heath, and barrens, while moist sedge-tussock meadows occur in valley bottoms. Black spruce forest occurs on some hills and ridges. Forests of white spruce, paper birch, and alder cover the low hills along the major rivers. Blackpoll warblers are common breeders in conifer stands in river valleys. Beaver are abundant, supporting a large annual harvest. Sockeye salmon are the most abundant fish. Chum, king, silver salmon, and rainbow trout are also numerous. The average annual precipitation ranges from , while the average annual temperature ranges from . The growing season extends approximately from May 15 to September 10.