How to Identify Douglas Fir Trees

Check the needle shape.

If you find a tree with needles that are 1 to 1.5 inches (2.5 to 3.8 cm) long, flat, soft, and flexible, chances are it is a Douglas fir. The needles should be dark green or bluish green in color with a blunt or pointed tip. The needle tips may even have a small notch at the end. They are initially attached to the twigs in groups of two but can later fall away leaving only one needle growing from where two were once attached together.[1][2]

Notice the branch arrangement.

Look at the branch arrangement. Douglas fir trees have branches that are arranged in a spiral shape. With most species of fir trees, their branches are all roughly the same length and appear to be growing outward from the trunk on more or less horizontal lines. The branches of a Douglas fir tree, however, grow in two distinct lengths: one set curves upward from the trunk and another set grows downward.

Examine the cones.

• Check the cones. Fir trees have both male and female cones, but you only need to identify one type for it to be a fir. The female cone can grow to 4 inches long, looks rather like a tiny pine cone, and is covered in sticky resin after fertilization. A Douglas Fir female cone will have a two-part scale where each half is shaped like a pyramid with an irregularly shaped tip. The bracts at the base of each scale are very short and barely visible. Male cones are small (less than 1/2 inch), yellowish-green, clustered together along branches on new growth, and shed pollen in early spring.

Determine if the tree has male and/or female cones.

• Determine if the tree has male and/or female cones. Douglas fir trees have male cones (pollen) at the end of their branches. Female cones are found on the lower branches or at the base of a tree. Female cones produce seeds while male cones produce pollen. Male and female cones do not appear on the same tree. If a Douglas fir you’ve identified has both male and female cones, it’s likely actually a grand fir.

Look for a gray-brown furrowed bark on older trees.

Since trees have such long lives, their bark changes over time. Younger Douglas firs have smooth bark in hues of red-brown to gray-brown with little furrowing. Older Douglas firs have rough bark in shades of red-brown to nearly black that is deeply furrowed into broad ridges and scaly plates. The bark is a protective layer for the tree and is made up of living and dead cells that insulate the tree against fire, insects, diseases, harsh weather conditions and mechanical injury (damage from people or animals).

The next time you’re out walking among Douglas fir trees take a moment to look at their bark. You’ll notice that there are lots of subtle differences between young and old trees!Happy Tree Hunting!

By identifying the needles and cones of a Douglas fir tree, you will be able to tell what type of tree it is.

To identify a Douglas fir, you should look at the needles. The needles on a Douglas fir tree always grow in pairs, but they don’t attach to a branch by way of a cluster or sheath. Instead, each needle is attached to the branch separately. Another characteristic of Douglas fir needles is that they are short and square-shaped. You’ll also notice that the branches of Douglas firs grow in a spiral pattern.

The cones found on this type of tree are also unique when compared to other types of trees. They are 3-6 inches long and dark brown when mature. The bracts that extend from them are longer than the cone scales themselves, which makes the cones appear larger and more visible than those found on other trees. Additionally, Douglas firs are monoecious—meaning they have both male and female cones—so you may see two different types growing on one tree at the same time.[END OF SECTION]