Identify: Tremendous Trees

Autumn is the season when trees explode in in a whole new palate of color and life.  The greens of spring and summer give way to an array of golds, oranges and reds to brighten the days and help us forget, for at least a moment, that winter is near.  Let's get ready for the season by taking a few minutes to learn how to identify 5 trees you might see while out and about in western Iowa this season.  For this list I went to an expert, Pottawattamie County Conservation's Kody Wohlers. Working in the Natural Areas Management Department as the county's Natural Resources Technician, Kody spends his days outdoors working with the unique ecosystem of the Loess Hills. He was kind enough to give me a list of his favorite native trees to share with our readers.

1. Red Oak (Quercus rubra)

The Red Oak tree is a common sight in Iowa.  In fact it is native to all but the northwestern tip of the state.  Height of this tree will range between 50 to 75 feet with some specimens reaching 100 feet!  It takes a while to get that tall though as Red Oaks will usually grow at a rate of 2 to 3 feet per year.  Red Oak trees can be identified by their unique leaves.  Rather than the rounded, lobed leaves common on some species, Red Oak leaves are characterized by the bristles or points on the leaf lobes.  Leaves will feature 7 to 11 lobes total and are a dull green on the top and pale green on the bottom.

Hardy & adaptable this species will produce acorns which mature in two growing season and sprout the spring after they reach maturity.  Coloration in the autumn will vary from red-orange to a deep reddish brown.

2. Black Walnut (Juglans nigra)

Black Walnut trees are incredibly valuable for their attractive and useful wood.  It is a high quality wood featuring a rich brown color with attractive grain patterns that is popular among woodworkers.  Iowa is one of the leading producers of walnut lumber and veneer.  This tree is useful for more than just its wood though. Common throughout the state it is most often found in bottomlands as it grows best in deep, well drained soil.  Black Walnut trees feature a distinct compound leaf, meaning smaller leaflets are clustered together around a central twig or stem to create the leaf as a whole.  1 to 23 leaflets will be arranged around the central stem, these leaflets are 2 1/2 to 4 inches long and feature a fine tooth-like pattern around the edges and tiny bristly hairs on the underside.

Black Walnut Tree in Fall Photo by Born1945 via Flickr, Black Walnut Tree Bark Photo by Albert Herring via Wikimedia Commons & Black Walnut Leaves & Fruit via Wikimedia Commons

The fruit of this tree is a round nut about 2 inches in diameter containing a single seed surrounded by a hard shell and a fleshy husk.  The husk will start it's season green and eventually turn black and peel off.  Anyone who has ever harvested these walnuts will remember the distinct color and smell of the juice.  This juice can actually be harvested and is used as ink by local artists.

3. Shagbark Hickory (Carya ovata)

The most common hickory in the state, the Shagbark can be spotted in most of the state but it is uncommon in the west central and northwestern counties.  This straight trunk tree can grow 70 to 80 feet tall and spread 30 to 40 feet at its crown.   The Shagbark Hickory has the distinction of being one of the easiest trees to identify because it's bark is so unique.  The grey-brown bark of a mature specimen will separate from the tree in large irregular strips that curve upwards at the bottom giving this tree its name.  The bark is very tough to cut as it has a high silica content and the wood is very impact resistant making it useful as tool handles, skis.  

Leaves are compound with 5 to 7 smooth, rounded leaflets with fine toothed margins organized around a central stem that will go from a rich green in the spring and summer months to a bold yellow in the autumn.  The fruit of this tree is a nut about 1 inch in diameter surrounded by a thick yellow-green husk.  The nut is difficult to open but is a favorite for a variety of species including squirrels, raccoons & nuthatches.

4. Eastern Redbud (Cercis canadensis)

Common throughout the eastern United States this small tree can be seen in most of Iowa in established woodland areas.  At 20 to 30 feet tall this beautiful tree is a common sight in landscapings throughout the area with an annual explosion of pink flowers beginning in March marking the approach of spring. The large, smooth rounded leaves have a very distinctive heart shape to them and are very glossy and thick.  During the autumn months they will become a bright yellow. The bark is vertically lines and has a pinkish hue to it as well and the fruit of this tree are a pod resembling a pea pod and contain 3 to 8 small bean like seeds.

5. Bur Oak (Quercus macrocarpa)

Common in all parts of Iowa the Bur Oak is the official state tree of Iowa.  Slow growing this species will reach 50 to 70 feet tall, some have surpassed 100 feet though.  The spread of this tree is impressive, reaching up to 70 feet wide if space is available.  Seed bearing will begin when the tree reaches maturity between 30 and 35 years old.  Acorns are set every 2 to 3 years which will mature in a single growing season and sprout when they fall in the autumn season.  Bur Oak trees feature single dark green leaves with large rounded lobes.  During the autumn the color will change to a dull yellow, yellow green or a yellow brown. The bark of a Bur Oak is a dark grey and very rough with deep ridges developing as the tree ages.  The 3/4 to 1 1/2 inch acorns are more than half enclosed buy a brown cup on the top featuring a unique and easy to identify yellow fringe.

This is just a small sampling of the trees you will encounter as you are out about this fall.  For help identifying these and other species the Iowa State University Extension Office has created a fantastic, interactive key to help you identify the trees of Iowa.  You can access this great tool through their website here.  

Originally Posted September 11th, 2014