City Trees is a premier publication focused on urban + community forestry. In each issue, you’ll learn how to best manage the trees in your community and more!
Issue link: http://read.dmtmag.com/i/115252
Partners Updates State Coordinators Urban Forestry in Northern Climates: The Alaska Experience by Patricia Joyner, Community Forestry Program Coordinator, Alaska Division of Forestry D o trees even grow in Alaska? Yes they do; in fact, the state has 126 million acres (51 million ha) of forestland—17 percent of all forestland in the U.S.! It does get cold but at one-fifth the size of the U.S., Alaska covers a diverse range of climatic conditions and vegetation types. The three largest cities—Juneau, Fairbanks, and Anchorage—are home to nearly 60 percent of the state's population and are representative of these differences. The state capital, Juneau, is in the southeastern coastal forest. It has a maritime climate with high precipitation, mild winters, and cool summers. The native forest consists of western hemlock (Tsuga heterophylla), Sitka spruce (Picea sitchensis), western redcedar (Thuja plicata), and Alaska yellow-cedar (Chamaecyparis nootkatensis). Many species that would not survive in most of the state thrive in Juneau's Zone 6-7 conditions, such as Japanese maples (Acer palmatum), beech (Fagus sylvatica), Katsura (Cercidiphyllum japonicum), dawn redwood (Metasequoia glyptostroboides), and others common in the Pacific Northwest. Alaska, with 365 million acres (147 million ha), is one-fifth the size of the entire U.S. Image from Alaska NRCS (Natural Resources Conservation Services), USDA At the other extreme is Fairbanks, 730 miles (1175 km) northwest of Juneau, where summer is warm and dry and winter is very cold and dry. Here, the circumpolar boreal forest is dominated by paper birch (Betula papyrifera) and white spruce (P. glauca). Black spruce (P. mariana) grows on wetter sites where permafrost is often present, and aspen (Populus tremuloides) and balsam poplar (P. balsamifera) are found on disturbed sites. The choice of non-native trees is limited in Zone-2 Fairbanks, where January temperatures average -2 to -18 F (-18 to -27 C) and extended periods of -30 degree F (-34 C) is expected. Siberian fir (Abies sibirica), larch (Larix), crabapples (Malus), and several species of Prunus and Pinus are common. Apples, Manchurian ash (Fraxinus mandshurica), and a few other hardy trees grow on warmer south-facing slopes and protected sites. Anchorage, the state's largest city, is in a transitional zone between coastal and boreal forests. Summers are mild and winters are moderate compared to the Interior. The forest is similar to the boreal forest; mostly paper birch, aspen, cottonwood, and white and black spruce. Anchorage is Zone 4 and has a long list of species that have proven hardy, including maples (Acer), bur oaks (Quercus macrocarpa), lindens (Tilia), 16 Fairbanks is in the circumpolar boreal forest; the native white spruce and paper birch are the most reliably hardy trees in the urban landscape. Photo by Patricia Joyner City Trees