What is Tree Flagging?
Ocean, Lake and Alpine Winds Shape Vegetation Patterns
Moderate Tree Flagging on Mistaken Island, Salish Sea, British Columbia, Canada
If you live near the sea coast, or perhaps one of the Great Lakes, you might notice the trees look uniquely appealing.
Trees develop a distinctive flattened pattern to their branches due to wind currents, sometimes displaying extraordinary levels of meteorological influence. Tops of trees so affected by high and persistent winds throughout their growing years may be heavily flattened and thus serve as especially useful nesting and perch sites for resident and migratory birds.
In high wind conditions, tree growth patterns may reach the point of flagging, where the branches are blown as the tree grows to the point where most or all of the branches sweep from the trunk to one side of the tree. The result is that the branches look like a flag on a pole. Alpine environments and arctic conditions also produce the high winds that cause flagging to occur.
Along the west coast of Vancouver Island, places like Pacific Rim National Park and the West Coast Trail display spectacular examples of flagging. Along the East Coast of Vancouver Island, small Islands such as Mistaken Island, pictured in a photo taken along the Vancouver Island shoreline also show trees exhibiting the pattern due to constant heavy winds on the water. The Great Lakes region of Eastern Canada and the United States also offers dramatic examples of flagging.