17. Succession of the Forest
If you look around this area of the forest you see numerous birch trees decaying on the forest floor. Birch is a relatively short-lived pioneer species.
Next you see a few large oak trees that probably survived the fires that moved through this area prior to settlement. New oak seedlings are unable to survive due to lack of sunlight.
Therefore, the oaks are replaced primarily by sugar maple, ironwood, and basswood. Without fire or other disturbances, this forest will turn into a primarily maple/basswood forest.