Posted by: Mary Stensvold, U.S. Forest Service Regional Botanist, Sitka, Alaska

Ever think about fall colors in Alaska? Now’s the time with autumn foliage colors peaking from late August to early October in Alaska’s Tongass and Chugach National Forests. However, since the national forests are in the temperate part of Alaska and are dominated by coniferous trees, the colors are generally not as spectacular as the brilliant colors of interior Alaskan trees and shrubs.

Deciduous trees such as red alder (Alnus rubra), Sitka alder (Alnus viridis subsp. sinuata) and black cottonwood (Populus balsamifera subsp. trichocarpa) occur on the Tongass National Forest. Their foliage generally turns yellowish-brown to brown before being shed. Yet, the Chugach National Forest tells another story, especially on the Kenai Peninsula with the yellows and oranges of quaking aspen (Populus tremuloides), Kenai birch (Betula papyrifera var. kenaica), and black cottonwood. The willow (Salix species) and high-bush cranberry (Viburnum edule) shrubs also turn yellow-orange and sometimes an added flash of red adorns the tips of their branches.

Notable fall color changes are visible in mountain alpine plant communities and bogs, where small shrubs and herbaceous plants provide swaths and splashes of color. On the Tongass, the first alpine frosts cause the deer cabbage (Nephrophyllidium crista-galli) to turn yellow-orange on the mountain tops before they are buried in snow. On the Chugach, bright red mountain avens (Geum calthifolium) contrasts brilliantly with bright green lichens above the treeline. Many bog plants gradually change color, with leaves of the tufted bulrush (Trichophorum cespitosum) turning a golden copper and then yellowish-brown. The Lapland cornel (Cornus suecica) and ripening small cranberry (Vaccinium oxycoccus) and lingonberry (V. vitis-idaea) turn a beautiful red, and sometimes sport a range of subtle shades of red. Deer cabbage also grows in many bogs with their leaves gradually changing to yellow.