In the Pacific Northwest, summer is transitioning into fall. Here fall is short, and quickly becomes winter. In the lowlands, where most of the population lives, winter consists of rain with mildly cold temperatures, mostly above freezing. Sometimes a snow or ice storm catches us off guard, since we don’t salt the roads for salmon safety. In the high country, snow comes quickly. It already blankets much of the Olympics, where just a month ago wildflowers grew.
Therefore, now is the perfect time to briefly discuss tree skirting. In a nutshell, tree skirting is subalpine firs’ response to snow coverage. The snow blankets the tree, protecting it from harsh cold and winds. The snow cover encourages growth at the tree base, forming the skirt. That is why subalpine firs sport luxurious branches at their base (This information comes from an interpretative sign at Hurricane Ridge in Olympic National Park).
It should be noted that tree skirting has almost the opposite definition in landscaping. It involves the removal of the lower branches.
Tree Skirting: Snow Shapes Subalpine Tree Growth by Shari Maria Silverman is licensed under a Creative Commons Attribution 3.0 Unported License.