Explore the Grounds

The restoration of Penn’s Woods began in 1944 as an effort to plant a large collection of Pennsylvania’s native trees on the property as a part of the first Pennsylvania Memorial Reforestation Project. Many of the trees that grow here still retain a tag that indicates the species and ID number that was posted at the time of planting (there is a free brochure for the Penn’s Woods Tree Trail available at the visitor’s center). While many different species of native trees were planted during this time, the area is typical of dry, upland forests in this region where oak, maple, beech, birch, tulip poplar and hickory predominate.

It is important to note that Penn’s Woods can be characterized as a secondary growth forest, as the mature trees that once grew here would have been harvested for lumber to accommodate the needs of a growing population up and down the river. Until 2003, the area was frequently mowed to give it a more “park-like” appearance, a practice that was discontinued in order to restore more favorable habitat for the many species of insects, birds, and other wildlife that live here.

Penn’s Woods now displays the forest layers, or stratification, typical of healthy forest ecosystems. First, notice beneath your feet that the soil layer is covered with leaves and fallen twigs/limbs/trees in varying degrees of decay (decaying wood and leaves harbor multitudes of insects and fungi that perform a valuable service in soil formation and water retention). Then, at arm’s reach, is the green herbaceous layer of diverse plants and shrubs that reflect the dappled sunlight reaching down from above. The understory of smaller trees and/or saplings is found just overhead, reaching for any bit of sunny opening where they may thrive. And finally, crowning over everything else, is the magnificent spread of branches that top mature trees—the layer known as the forest canopy.

Make sure you look for the Moss Garden, the R.O.T. Plot and the Gazebo in Penn’s Woods, as well as the many wildflower species that bloom here, especially in the spring. Penn’s Woods is a healthy, diverse forest ecosystem that preserves the unique natural heritage of our area.

Moss Garden

A short walk into the Penn’s Woods section of BHWP delivers you to a large clearing carpeted in beautiful, emerald green moss. Visitors who take the time to get down on their knees to touch and examine the moss up close will find that there is much to see—tufts and mounds and velvety expanses of tiny green plants—almost like an entire forest ecosystem in miniature!

The beauty and tranquility of this space is exactly what was envisioned several years ago when the Preserve launched the moss garden project. The idea stemmed from the abundant presence on the Preserve of naturally occurring mosses (known as bryophytes), a type of primitive, low-growing and mostly shade-loving plant that has no root system. Instead of having flowers, mosses reproduce both vegetatively—with little bits of mother moss plants breaking off to produce new plants—and through spore-producing capsules (sporophytes) that rise like tiny hairs above the green carpet. Mosses have long covered the walking paths in Penn’s Woods, and it seemed a worthy endeavor to expand this unique forest floor ecosystem into a larger area.

On Earth Day 2013, a group of high school volunteers cleared brush and leaves from the area all the way back to bare ground—the perfect substrate for the colonizing of soil-dwelling mosses. After clearing, the pH of the soil was lowered (through minimal chemical treatment) to better accommodate these mosses and to discourage weeds. Then a moss-collecting hunt by the students all over the Preserve resulted in a large harvest of moss clumps to distribute evenly over the soil. With a little time and consistent moisture, the mosses easily began to spread across the area.

Along with the large, flat rocks (locally quarried argillite stone that symbolizes the geological significance of the Preserve) that anchor the clearing, the moss garden has become an area of tranquil beauty that successfully blends an appealing, meditative aesthetic with the important ecological role that mosses play in forest ecosystems.