Douglas fir forest along Limantour Road, Point Reyes National Seashore

Choose one of the canopy layers and see what other species are found in the Douglas fir forest.

Similar to the bishop pine (Pinus muricata), the Douglas fir (Pseudotsuga menziesii) was also once more widespread throughout California. Today, it clings to this southern outpost (Evens 1993) of a more extensive and contiguous northern forest that extends as far north as British Columbia. There are also a few patchy forests along the southern and central California coast. On the Point Reyes Peninsula, the Douglas fir community is located at the southern end of Inverness ridge and is associated with Monterey Shale. The annual precipitation at this end of the Ridge averages 30 to 42 inches which is easily accommodated by the well-drained siliceous and sandstone soil (Evens 1993; Johnston 1994; Kricher 1993).

Even though P. menziesii was heavily logged in the 1950's, there are still several large virgin stands on the Peninsula. Today, some of these individuals even rival redwood trees (Sequoia sempervirens) in height and circumference. The best examples are found along Bear Valley Trail, the Vedanta Trail and on the Bolema and Greenpicker Trail on Inverness Ridge (Evens 1993; Shuford & Timossi 1989).

Fauna

In general, the Douglas fir community has a wide array of wildlife. However, the red tree vole (Arborimus longicaudus), red tree mouse (Phenocomys longicaudus) and Douglas squirrel (Tamiasciurus douglasii) are three important indicator species that appear to be absent from the Peninsula's isolated Douglas fir forest. In the more extensive populations of P. menziesii in Oregon and Washington, the red tree vole (Arborimus longicaudus) relies exclusively on the Douglas fir for food; the red tree mouse (Phenocomys longicaudus) is an arboreal rodent that lives high in the canopy of the coniferous forest; and the Douglas squirrel (Tamiasciurus douglasii) lives in moist coastal forests such as fir, spruce and hemlock but is missing from this otherwise perfect environment on Inverness Ridge (Evens 1993; Johnston 1994; Kricher 1993). Why are these three species absent from the Peninsula's Douglas fir forest?