What Kind of Tree is This?

Spring 2016

Can’t tell you how many times I’ve heard: “Hey, you’re a forester; what kind of tree is this?”

For many foresters, we would rather confront a bear in the woods than hear that brief question. We’re fine answering that question in our local forest with native trees, but while looking at a non-native tree we’re quickly reminded that our college Dendrology course came down to a one-question final exam with either a pass or fail grade. No matter if we took this course last semester or 40 years ago, our reputation is on the line.

Every forester, usually as a freshman, takes Dendrology which literally translates as the “study of trees.” And for decades, the Textbook of Dendrology, published by McGraw-Hill Book Company, Inc. in their American Forestry Series, became each student’s bible.

In the introduction, authors Harlow and Harrar begin with, “A knowledge of the names of trees, their habits, and principal botanical features is basic to advanced studies in forestry.” Dendrology teaches not only tree identification, but perhaps more importantly, the knowledge and methods to be able to identify unknown species.

Dendrology lectures focused on basic tree identification characteristics. Since leaves provide important clues to a tree’s identity, students learn about leaf arrangement, leaf composition, leaf shapes, leaf venation, and leaf surface features.

But leaves are not always present. Flowers (yes, trees have flowers), fruits, twigs, buds, and bark all become important identifying characteristics on a leafless tree.

My dendrology course took place in southwest Louisiana where bottomland hardwoods prevailed in any forest not planted with southern yellow pines: loblolly, slash, longleaf or shortleaf. The professor warned us that the deciduous tree we easily identified by its leaves in September would be bare during our field exam in January. Sassafras, for example, has three distinctively shaped leaves on the same tree making it easy to identify. Recognizing this species by its twigs and bark, however, requires some skill. For a real test, try picking out about a dozen different oaks just by their bark.

Going back to that dreaded question, foresters feel comfortable in identifying native trees growing in the forest within their local area. We can usually look from one ridge to the next and easily pick out native conifers just by the shape of their crowns. But we quiver in our boots when asked that same question in someone’s backyard, or especially, on an old farmstead. That’s because there is no way of predicting what non-native species were planted with origins from who knows where. Since many settlers migrated to this area from the mid-west or Lake States, it’s not unusual to find a mid-western hardwood or two transplanted from the old family farm in Indiana or Michigan.
Over the years I’ve been asked to identify northern red oak, bitternut hickory, and American elm growing in North Idaho. In regard to conifers, I’ve seen bristlecone pine and giant sequoia. Who knows how they got here or why they survived. (The sequoia trees did well for several years but eventually succumbed during an extremely cold winter.)

Probably the second most-asked question for a forester: “…can you recommend a good book on tree identification?” The answer, of course, is yes and it’s not just limited to printed publications. A search of the internet becomes a quick source to learn about tree identification. But for those of us who like the feel of a book in our hands, most of the regional plant guides, available from local book stores or on-line sources, have sections on native trees. I especially like a series from Lone Pine Publishing based in Canada.

Although out-of-print, Wild Trees of Idaho, by Frederick D. Johnson is available at Amazon.com but, let me warn you, the few available new copies now bring about $180. Fortunately used copies start at $40. Another source is the University of Idaho website where a PDF version can be viewed online or downloaded to your computer. Regardless of how you obtain a copy, you will learn about trees in Idaho.

Another good source of information on tree and plant identification is “Plants of Southern Interior British Columbia and the Inland Northwest” by Parish, Coupe and Lloyd. This book is a great “take it with you” guide to the flora world.

So next time you see a forester, be sure to ask, “… you’re a forester; what kind of tree is this?”– Bill Love, CF