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How to Identify Oregon’s Most Common Trees

Whether you’re looking to get more into nature, impress your arborist friends, or simply display your Oregonian pride, you might want to learn more about the native trees of Oregon. It was our own curiosity and interest in trees that got us started in the tree care business decades ago. At Mr. Tree, we enjoy caring for trees, studying trees, and enhancing our knowledge of them. And we’re more than happy to share that knowledge with you. So grab yourself a seat out in your yard and use this handy guide to learn how to identify trees native to the Beaver State.

The first thing you’ll want to do is familiarize yourself with some of the more common native trees of Oregon. The Douglas fir is Oregon’s state tree and is the most common tree found here. While the Douglas fir is more common to western Oregon, it can be found in both the western and eastern parts of the state. In fact, it’s native to 35 of the state’s 36 counties (Sherman County is the exception, in case you were wondering). The Douglas fir is characterized by its flat pine needles and small pine cones that have pitchfork-shaped scales. 
How to Identify Oregon's Most Common Trees
The most common native trees of western Oregon include red alder, hemlock, and bigleaf maple. Native trees of eastern Oregon include the ponderosa pine, western juniper, and grand fir, just to name a few. For a more comprehensive list of Oregon trees, check out this Oregon State University resource. Click on the name of each tree to learn more about them and some of their identifying characteristics.

Now that you’ve familiarized yourself with some of Oregon’s more common native trees, let’s get started on identifying them in their natural environment. One of the telltale signs of a tree’s identity is its leaf. The first thing you want to do is identify if the tree is a conifer or a broadleaf tree. Conifers will have needles or scales as leaves. The Douglas fir tree is an example and there are close to 30 other conifer species native to Oregon. Broadleaves, on the other hand, will have flat, thin leaves that change color in autumn and fall off during winter. They may also bear fruits or flowers.

Next, you’ll want to look at the spacing and shape of the leaves. On a conifer, are the needles spaced evenly apart or bunched together? On a broadleaf, are there multiple leaves on a branch or just a single one? This graphic illustrates the difference. Once you’ve considered the spacing, take a look at the leaf shape. For a conifer, consider how long the needles are and whether they’re different colors. For a broadleaf, look at the edges of the leaves. Are they smooth or jagged? Are the leaves thick or thin? Is there any type of fruit or flower growing on the tree? Paying attention to these details will help you narrow down the field of potential tree species.

Now that you have a basic understanding of native trees of Oregon and what to be on the lookout for, you’re ready to start using a dichotomous key to identify the tree species. Ever take one of those maze-like quizzes where you have to answer one way or the other and each response will take you in a different direction to the next follow-up question? That’s kind of how the dichotomous key works. We’ll start with what we just went over.

Your first task will be to identify whether the tree is a conifer or a broadleaf tree. Then you’ll go from there. It’s a good idea to get up close and personal with the tree that you’re trying to identify. It will be important to observe the tree’s characteristics in great detail so you can answer the questions accurately. You should also have a ruler in hand to take any measurements you might need. Let’s walk through an example to get you started.

We’ll use the most common species, the Douglas fir tree, to go through the key. If possible, try to find a Douglas fir tree or at least look at a photo as we walk through the key together. We know the Douglas fir is a conifer so the first question will be easy to answer. Next, we’ll want to observe the tree’s leaves. Are they needle-like or are they flat with scales? The tree’s leaves are pointed like needles so we can select that answer and move to our next question.

Are the Douglas fir tree’s leaves clustered? The tree’s needle-like leaves are spaced fairly evenly apart so we’ll select the ‘not clustered’ answer. Now, let’s observe the length of the needles. Are they longer than a half inch? The Douglas fir tree’s needles are about an inch in length so we can select that the needles are longer than a half-inch and move to the next question. But note that if the needles were short and sharp we would have already identified the tree as a giant sequoia. Some trees will require you to answer more questions than others.

Are there any pegs on the twigs? None from what we can tell so select the ‘no pegs on twigs’ answer. Now, take a look at the tree’s buds. Are they large and pointed? Yes, they are. Voila! We have our answer. We’ve identified our tree as the Douglas fir tree. Once you have the correct answer, the key will take you to a page that provides more information on the particular tree type you’ve identified. That was relatively easy, right?

Want to practice on your own? Select a mystery tree and go through the dichotomous key again. You’ll answer the questions based on the information provided. Then you can see how closely you’ve paid attention and how much you’ve learned so far.

After you’ve completed the key for the eight trees, you can go to the solutions page to see how many you were able to identify correctly. If you get a few wrong, no reason to worry. It took years of practice for us to become expert arborists. So keep practicing. And remember, once you’ve identified your tree, contact us here at Mr. Tree for all your tree care and maintenance needs.