When David Douglas visited Oregon in 1826, he noted that the low hills of western Oregon were covered by Oregon White oaks and grass. This oak savanna land was formed through fires set by native people and lightning. The mature oaks were able to resist these mostly low-intensity fires that cleared the ground vegetation.
As a result of fire suppression, coniferous forests have closed up these open landscapes. Because the Oregon white oak is intolerant of shade, the oak savanna habitat has declined. That said, small remnants of this landscape can still be seen out at the arboretum and throughout the Willamette Valley.
In the forest above the White Oak Pavilion, there is an example of this phenomenon. An old, dead oak tree can be seen in the shadows of towering Douglas fir and incense cedar trees that have taken over the hillside.
