Planting Fruit Trees Shade Trees and Berry Plants in Alaska
Alaska's temperatures over several centuries progressively have decreased by 25 degrees to 30 degrees Celsius. Fruit trees have been successfully grown near the University of Alaska at Fairbanks by planting the fruit trees in orchards, the fruit trees facing South, midway up hills. This special planting prevents fruit trees from being damaged by sun scald that occurs during “ Indian Summers” (Chinook), that prematurely thaws plant tissues on the sunny side of the tree, only to be damaged by sudden refreezing after dark.
A gardener from Alaska is faced with extreme cold temperature, preventing his harvesting a juicy apple in the fall, even though the USDA growing zones range of zone 7 in the extreme Southern islands. Although most fruit growers in AK can grow almost any fruit tree inside a heated home or greenhouse, that is impractical for many garden enthusiast. Crabapple trees are the best apple tree pollinators and the Oregon crabapple ( Malus diversifolia) and the Siberian crabapple tree ( Malus baccata) are often used as a pollinator or as a cold hardy rootstock for fruiting apples like the Lodi apple. Cherry trees such as the North Star Cherry and the Montmorency Cherry are recommended for Alaska if grafted onto a cold hardy rootstock.
Blueberry plants are cold hardy and blueberries are a favorite native bush to grow in Alaska. Blueberry plants are native to Southern Alaska soils. During the Fall the leaves of the blueberry plant turn a brilliant scarlet color. Plum trees can be grown in Alaska, but some winters the plum tree is not as cold hardy as cherry trees or apple trees.
Even though only a few tree species grow on the interior of Alaska, fossil excavations show that years ago, before the intrusion of glaciers, nut trees such as hickory, chestnut, walnut and also hazelnut trees grew there. Shade trees such as Oak tree fossils were found next to sweet gum shade tree fossils, basswood and beech trees. Holly shrub fossils also were found.
The six principal trees found to grow on the interior of Alaska as shade tree, native trees are Quaking Aspen, balsam poplar and paper birch. The evergreen native shade trees are white spruce and black spruce and the tamarack larch, a deciduous conifer tree.
Other trees found on Alaskan fringe areas that survive as cold hardy trees are balsam fir, willow tree, yellow cedar, alder and pine trees.
Unlike New England shade trees that change into brilliant fall colors of crimson, purple, scarlet and gold, the Alaskan forest shade trees only change to gold, never New England fall colors.
Irrational as it may seem, trees grow twice as fast in Alaska as in lower Massachusetts. Research has shown that Alaska has unique growth periods, because the tissue hardening time-line in late summer is accelerated by drastic day length shortening and steep, progressive temperature drops. As the plant cells harden off due to the decreasing temperatures, the cells become progressively less hydrated by water and thus, more cold hardy. Centuries of genetic cold hardy selection has evolved races of plants and trees in Alaska that grow faster, become their environmental growing season has been constrained and only the most cold hardy species have evolved into a faster- growing tree, and that has been translated into a characteristic of fast growing, cold hardiness. Only a few species have become in the evolutionary cycle removed from the tundra, because of the extreme temperature fluctuations leading to a low biotic diversity.