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  • Writer's pictureDave Wallbridge

Red Alder: The Original Pioneer of the West

The Pacific Northwest is an area characterized by, and famed for its gigantic trees. The weekend

hikers to the full-time tree enthusiasts are captivated by the West Coast giants such as Sitka Spruce, Douglas Fir, and Western Red Cedar; and rightly so. These giants though, are standing on the shoulders of an altogether more unassuming and inconspicuous hero of the tree world. The Red Alder.

Those familiar with the forests here will recognize Red Alder as a relatively short-lived, fast growing deciduous tree; certainly not one famed for its enormity or longevity. However, it is beautiful in its own right. Mottled grey-white bark, leaves that retain their bright green colour all the way to leaf drop, and burning red winter buds adding streaks of colour to woodland borders prior to the break of spring. The hidden beauty of Red Alder though, is in its pioneering spirit.

A pioneer species is one that is typically first to thrive in a baron ecosystem, leading the recovery of that ecosystem and making it habitable for other species down the line. New, or recently disturbed ecosystems rely on the success of early pioneer species to lay the ground work for future success.

So what makes Red Alder such an effective pioneer? First of all, Alders can pollinate via wind, in areas that are devoid of insect pollinators. They are monoecious, meaning both male and female flowers (catkins) are present on the same tree. After pollination, female catkins produce a high volume of seeds that are widely dispersed by wind and water. Another reason that Alders get the jump on other tree species is the lack of nitrogen availability in the soil of recently disturbed ecosystems.

Trees love nitrogen, and the huge trees of the Pacific North West are no exception. Fortunately, Red Alders are nitrogen fixers. They benefit from a symbiotic relationship with bacteria called Frankia, which populate the roots of Red Alder. Frankia are able to capture atmospheric nitrogen and convert it to ammonia, which Alders are then happy to use for their essential processes.

Furthermore, most deciduous trees tend to recycle nutrients from their leaves prior to leaf drop, but not Red Alder. Alder leaves will drop while they’re still green, returning all those nutrients directly to the soil and quickly creating a nitrogen-rich humus. In a few short years, Red Alder can transform a baron, nutrient-deficient landscape into a nutrient rich, stable, sheltered and progressively complex ecosystem that gives larger tree species a place to thrive.

So during your next walk in the woods, take a moment to draw your gaze down from the heights.

Look to the borders, the clearings and the riversides, and pay homage to the modest mottled barked pioneer who made it all possible.


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