Oak Tree and Acorns

Photo by Stan Tekiela

by Stan Tekiela
© NatureSmart

October 29, 2023

One of the most important parts of any forest ecosystem or ecology is the mighty oak tree. It is often a huge sprawling tree with thick heavy branches, large dark green leaves and a trunk covered with thick bark. There are approximately 500 species of oak tree found all around the world in the Northern Hemisphere. They grow from the cold temperate regions down to the tropical latitudes. They occur in Asia, Europe, North Africa and of course North America.

North America has the most oak species with approximately 90 distinct kinds of oak in the United States. Oak trees are one of my favorite trees but NOT at this time of year. More about my beef with oak trees shortly. They are an ancient group of trees. The oldest fossil record in North America dates to the Middle Eocene, around 44 million years ago, and was found in Oregon. In other parts of the world, the fossil record dates to 55 million years ago.

They are such an amazing and incredibly diverse group of trees. For example, most oaks are deciduous, which means they drop their leaves each fall and grow new leaves in the spring, but some oaks are evergreen, holding their leaves all year long just like evergreen trees. Not many tree species have this kind of diversity.

Oak trees can be broken down into 2 different categories or groups. The White Oak group and the Red Oak Group. The difference can be seen in the leaves. All the oaks in the White Oak group have round tips of their leaves. While all of the oaks in the Red Oak group have pointed tips. This is a quick and easy way to group the oaks.

In addition, White Oak trees produce flowers each spring. Yes, I know, you are probably thinking right now that you’ve never seen oak trees with flowers. That is because oaks have small green flowers that occur in early spring before the leaves start to grow. These flowers, after being pollinated, turn into acorns. White Oaks produce acorns every year. The Red Oaks also produce flowers in the spring, but the resulting acorns don’t mature and fall from the tree until the following year. Red Oaks produce acorns every other year. So, if you have an oak tree in your yard and you are only raking up acorns every other year you have a Red Oak type of tree. If you are raking up acorns every year, like I do, then you have a White Oak type of tree.

The acorn is how the oak tree reproduces itself. The word “acorn” comes from the combination of two words, “corn” and “oak-horn” which both refer to an important food source. By the 15^th and 16th centuries the words were combined to make the Old English word “acorn” which we use today.  

Acorns are an extremely important food source for all sorts of wildlife. Everything from tiny mice all the way up to bears and moose eat acorns. Each autumn, White-tailed Deer eat large amounts of acorns. Some studies estimate 25 percent of a deer’s autumn diet is made up of acorns. Birds such as jays, turkeys and ducks also eat a high volume of acorn. Of course, it’s not surprising that woodpeckers eat a lot of acorns also.

The acorn is the oak trees’ way to reproduce and send new copies or versions of themselves out into the world. The problem is, no one wants their children growing at their feet or under their branches. Acorns are too large to be dispersed by or carried away by the wind, so they require other ways to spread out. They need a biological seed dispersal agent to carry or move their seeds away from the mother tree and into a suitable area with enough sunlight and soil nutrients to sprout and grow.

The main biological dispersal agents for the oaks are squirrels and jays. Both squirrels and jays are considered scatter-hoarders and will cache large amounts of acorns for later consumption. Even though squirrels and jays have remarkable abilities to remember where they have stored each nut, a small percentage are never recovered, and these forgotten acorns are the ones that germinate and produce new trees away from the mother tree.

Now for my love/hate relationship with oak trees. My house is located under many very large White Oak trees and this year I am being buried alive under a mountain of acorns that fall like rain when the wind blows. It is so bad that I can’t park my truck in the driveway for fear it will be completely covered by acorns by morning. Forget about walking down my driveway, because it is like walking on a thousand marbles, threatening to twist an ankle at any moment. I do my best to clear away the acorns but somedays it feels like I am fighting a loosing battle. Until next time…

Stan Tekiela is an author / naturalist and wildlife photographer who travels the U.S. to study and capture images of wildlife. He can be followed on www.instagram.com and www.facebook.com. He can be contacted at his website www.naturesmart.com.