Western Hemlock

Western hemlock is the patient tree of the Cascade forest. Its seedlings tolerate deep shade, so in an old forest it slowly fills in beneath the Douglas-firs, and after several centuries without a major disturbance it can take over almost completely. That makes it what ecologists call a climax species, though it also moves quickly into open, sunny ground.

The easiest way to recognize one is to look up. The top of a western hemlock droops over like the tip of a fishing rod, and the branch ends hang down too. Up close, the short, flat needles come in two distinctly different lengths on the same twig, green on top with two white stripes beneath, and the egg-shaped cones are only about an inch long.

Hemlock seeds sprout readily on rotting wood as well as on forest litter and bare soil. Thin bark, shallow roots and low, lichen-covered branches make the tree easy to kill with fire, so it does best in cool, damp places where fires are rare. Elk and black-tailed deer browse it, and in the western Oregon Cascades its forests shelter northern flying squirrels and red tree voles, while cavity-nesting birds use the trees for nests.

On Mt. Hood it is common in moist forests of the lower and middle slopes, especially in shady valleys and on north-facing ground. Higher up, its relative the mountain hemlock takes over.