Certainly trees do not grow as rapidly in interior Alaska as they do in Washington and Oregon. Nevertheless, the rate of tree growth in Alaska often surprises the newcomer. The reason for this is that trees in Alaska appear to be adapted to grow more rapidly when the conditions for growth are favorable during the short but relatively warm summer. Recently two scientists combined their efforts to investigate growth rates of white spruce in Alaska and Massachusetts. Bob Gregory in Alaska and Brayton Wilson in Massachusetts carefully measured the rate at which new tracheids were formed by the camblum.
Tracheids are the cells that make up the wood in the formative cambium layer.
Gregory and Wilson found that trees in both areas formed the same number of tracheids but that the white spruce in Alaska produced most of these cells in about one-half as much time as it took the trees in Massachusetts. In other words, the cambium in Alaskan trees was producing tracheids at a rate twice that of the Massachusetts trees. Thus, it appears that white spruce, and other trees, which grow in the Far North are genetically adapted to the unique growth conditions which occur here. All studies show that these trees grow very slowly at lower latitudes. In order to make them grow as fast as they do here, the length of the day has to be increased to match our Alaskan summer day.