Oregon Garden – Oak Grove

2015.05.28

Oak woodlands and savannas were once common in the Willamette Valley, but metropolitan and agricultural development, monoculture conifer plantations, and fire suppression have reduced this ecosystem to well under 10% of the historic extent.  Although humans are largely to blame for the decline, we were also the primary cause for their spread over the past few thousand years.  The Kalapuya and other tribes set fires to clear saplings of Douglas-fir and other species, allowing the fire-tolerant oaks to thrive.  This “managed” landscape fostered food sources like camas, tarweed, nuts, acorns, berries, and deer.

The Oregon White Oak (Quercus garryana) ranges from California to British Columbia; in the northern half of that range it is the only native oak species.  They are slow-growing, drought-tolerant trees, eventually reaching 60 to 100 feet over a potential lifespan approaching 500 years.

Many of the oaks at the Oregon Garden are 100 to 250 years old, but one has stood for over 400 years.