Western redcedars: the trick is butterflies ...

Western redcedar, thuja plicata, is common throughout the Pacific Northwest, at least west of the Cascades. It is in the cypress family, Cupressaceae. How do you tell for sure that a tree is a western redcedar and not one of its less-common cousins?

There are a number of other trees in the cypress family that are native to the Pacific Northwest. These include Alaska yellow-cedar, incense cedar (in Oregon), Port Orford-cedar (in Oregon), and several species of junipers.

There are also a large number of cypress hybrids and cultivars that are widely planted for landscaping in the Pacific Northwest. Common examples are Leyland cypress and Hinoki cypress.

All these trees have leaves that look like scales. At a quick glance, any one can be mistaken for another.

So what's the easiest key to distinguishing western redcedar from these cousins?

The trick is butterflies.

Hold a branch of the scale-like needles. Turn it upside-down. The scales of western redcedar are imprinted with white patches of stomata that look just like butterflies!

These butterflies are an easy ID for western redcedar.

On some cousins, scales have an "X" on the back. On others, there is no back or front at all. 

Look for the butterflies of western redcedar. Teach your kids too!

Back to Resources →