Forest Succession

A forest goes through many stages of growth and development. The most common term used for these processes is succession. This happens in a somewhat predictable fashion, so if you can identify some of the indicator trees or plants that are prominent in a successional stage, then you can roughly estimate the age of a forest stand. In Appalachian Kentucky early successional species include black locust, eastern red cedar, tulip tree and sassafras. Succession of tree species affects everything else in the forest. Not only do the tree species change and grow, but the forest understory and habitat for wildlife change as well.

There are five successional communities that arise when a forest goes from an abandoned field to a mature forest. Availability of light, soil nutrients, and moisture will determine which species tend to proliferate and ultimately dominate. Depending on site productivity and human intervention, this process can take centuries to develop fully.

Click here to see a slideshow that illustrates the five stages of forest succession: pioneer, transition forest, young forest, mature forest and old growth.

photo: Sara Thilman

Crowns of trees create a canopy which eventually will block out sunlight. These trees are tall, but there are still some gaps in the canopy allowing sunlight to reach trees below.

Determining the Age of Your Forest

Determining the exact age of a forest is a precise science requiring professional equipment. However, there are means by which to obtain a ball park estimate. Based upon the principles of succession you can walk through the forest and look for key indicators. If you see an area that has shrubs and small trees then you can determine that this is a very young forest. A forest with large trees and a closed canopy, which does not allow much sunlight through, is likely a mature forest. Depending on the tree species and soil type it is possible to have very small trees that can be over 100 years old.

Recognizing a Transitional Forest

When walking your forest it is important to recognize that different areas within your property might have forests at different stages of succession. You may notice an abundance of pine or cedar on the edge of a mature forest. This is a sure sigh that this area is still in transition to mature forest. To best identify stages of succession it is helpful to know which species need sunlight and will therefore dominate the canopy.

Recognizing a Mature Forest

In the southeast, typical indicators of a mature forest are large hardwood trees that are well spaced among each other with little understory vegetation. The lack of understory vegetation is a result of the trees canopy closure, which blocks sunlight from reaching the ground. However, upon walking your forest you might encounter areas of dense vegetation within a mature hardwood stand. This is more than likely a result of a disturbance where a mature tree fell. Once a tree topples or is cut, sunlight is able to penetrate to the forest floor and promote vegetation growth.

 

 

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