Bridge Creek Research Natural Area Establishment Record

The Bridge Creek Research Natural Area is distinguished by its old growth Douglas-fir hardwood forest with a significant white fir and giant chinquapin element. It covers the majority (slightly under 80%) of the RNA. The forest is generally well developed, much of it being spared from even minor ground fires for over 150 years. Consequently, the multi-layer structure of the forest is typically very pronounced.

Mature Douglas-fir forms an open canopy of trees up to 220 ft (67 m) tall and 6.5 ft (2 m) diameter at breast height (dbh). Beneath this is a sub-canopy of white fir, giant chinquapin, younger Douglas-fir, and Pacific madrone. Below the subcanopy is a small tree layer dominated by species such as Pacific yew (Taxus brevifolia), Pacific dogwood (Cornus nuttallii), and vine maple (Acer circinatum). Below the small tree layer lies a frequently dense shrub layer composed of Sadler oak (Quercus sadleriana) and scrubby saplings of giant chinquapin and tanoak. The lowest stratum is the herb and low shrub layer which is dominated by such species as Oregon grape (Berberis nervosa), wood rose (Rosa gymnocarpa), pipsissiwa (Chimaphila umbellata var. occidentalis), twin flower (Linnaea borealis), vanilla leaf (Achlys triphylla), and rattlesnake-plantain (Goodyera oblongifolia).