Where I used to live in Bucks County, Pennsylvania, you could go into a soothing forest, yet only see trees. You should see trees, yes, however you shouldn’t ONLY see trees! In this area, the land was disturbed and cleared for agricultural purposes. Now, many field properties are transitioning and going through succession into forests. However an integral part of the forest is missing – the understory! To uncover why this is, let’s start with defining forest succession and identifying some of the wildlife that call these forests home.

Forest Succession

Forest succession happens as a meadow ages and naturally transitions into a mature forest. When meadows aren’t managed by people, changes happen. Animals drop seeds from other plants and slowly, thickets and shrubs start to grow up through the flowers and grasses. These shrubby plants provide shelter for tender saplings to grow. Eventually, the saplings grow taller, becoming young trees. They start shading out grasses, but the thickets and shrubs remain. What once was a full sun meadow has the protection a forest canopy. Now, plants that are specially adapted to a shadier environment can move in. The growing canopy creates a cooler, moister microclimate. Ferns and mosses thrive, and delicate woodland flowers can bloom without fear of the scorching hot sun. Eventually new saplings grow, patiently waiting for an older tree to die and let light in through the canopy’s hole.

While the understory changes as a forest ages, there should be an understory filled with tree seedlings, shade-loving plants, and shrubs. So where did those plants go?!

Wildlife that Live in Pennsylvanian Forests

Let’s think – what utilizes plant life? Humans definitely do, however these forests of Southeastern PA aren’t under threat of logging for the most part. Even though some forest is lost during development, humans don’t cut just the understory, the whole forest goes away! That leaves us to consider the impact of wildlife on understory life.

In Pennsylvania, the herbivorous White-tailed Deer population is extremely high. In 2001, after successful attempts to protect the deer, especially after being hunted almost to extinction upon arrival of the settlers, the population soared and there was a reported population of 1.5 million deer in the state (2-3x more than were thought to be here prior to European settlement)! While it’s great that deer made a comeback, 1.5 million is too much. Deer have a tremendous impact on the forest.

Impact of White-tail Deer on Forests

White-tailed deer like to browse on young buds and plant tissue. In moderation, this helps prune the plants and stimulate growth, however when there are too many deer, they eat too much for the tree to recover. This limits tree and understory (the young plants) biodiversity. When the understory is over-eaten, there is not enough other plant life to provide for the numerous other wildlife species that rely on a healthy forest environment. Raccoons, opossums, skunks, fox, squirrels, and rodents would love to utilize a healthy forest, but are often forced to turn elsewhere and find their way to our trashcans.

Over-browsing can also impact the ability of animals to find shelter. Without thickets, shrubs, and other understory growth, prey animals won’t have great hiding places. Birds loose nesting habitat and reptiles, such as the Eastern Box turtle, have to search elsewhere for places to lay their eggs.

Ways to Support Healthy Forests

If you have a woodlot, consider putting up a tall fence called a Deer Exclosure. These fences are too tall for deer to jump over, allowing the forest within the fence to thrive without being over-browsed. Also consider planting not just trees in your community or yard, but also native shrubs! Shrubs allow the animals to move back into the area to nest, raise young, find shelter, and get food.

By getting outside, learning more about the natural world and the interconnectivity of ecosystem life, you can help make the land around you thrive! Explore upcoming events designed to enhance your understanding and connection to the natural world. You can also support The Art of Ecology through art purchases, podcast support, and on Patreon. A portion of the proceeds benefits wildlife conservation and habitat preservation efforts!