What is a mixed mesophytic forest?
Mesophytic means moderate loving and refers to plants that prefer moderate levels of soil moisture and temperate climate. Mixed refers to a mixture of species that may include both evergreen and deciduous trees. These forests are very diverse, with many species of trees, and exist on deep, well-drained soils. The soils are rich in nutrients and possess

The Significance of a Stream
in the Overall Scheme

In addition to being designated as a Pennsylvania Scenic River and an Exceptional Value
Stream, Bear Run can be a very vocal waterway. Depending upon water level, you will hear either its roar or gurgle long before you approach the first of Arbutus Trails four bridges.
From the middle of these structures, hikers find unobstructed views of the stream. The stream flows through a gauntlet of rhododendron, winds its way through old hemlock and over rock formations that at times produce a spectacular array of rapids and waterfalls. Tumbling over moss-covered rocks, dodging lichen-encrusted boulders, and pouring a smooth, even flow across sandy, leaf-littered terraces, the stream relentlessly follows its carved path of least resistance as it descends more than 1,500 feet to the Youghiougheny River. Because of protective forest cover on the land it drains, land that has been protected for many years, the stream runs clear.

Over the years, first the Edgar and Lilianne Kaufmann family and then the Western Pennsylvania Conservancy have continually acquired additional properties to enlarge the boundaries of Bear Run Nature Reserve. Today, WPC owns most of the entire watershed,
protecting it from development and allowing it to remain in forest. As a result, the forest surrounding Fallingwater and within the Bear Run Nature Reserve is more intact today than it was at the turn of the 20th century.

The Bear Run Nature Reserve lies within the Allegheny Mountains of Pennsylvania. As the mountains extend through West Virginia north through Indiana County, they draw southern influences north through the valleys and northern influences south along the ridges. Mixed mesophytic forests extend north through southern Fayette County. The forests along the big rivers like the Youghiogheny show some of the richness that characterizes these forests. The Allegheny Mountains support a number of animal species, like the green salamander, and plant species, such as the American bugbane, that in Pennsylvania are confined to these forested mountain ecosystems.

Tramroads were common during the heyday of lumbering in western Pennsylvania and extended lumbering into previously inaccessible forest areas. Traces of tramroads remain at Bear Run Nature Reserve.

What makes the reserve significant is its size and that it represents an important forest
ecosystem, noted WPCs Heritage Program Director Jeff Wagner. You have big blocks of contiguous forests in north central Pennsylvania and, to some extent, in the central Appalachians. But they’re northern forests, with their associated plants and animals. The forests of the Alleghenies and, to an extent, those of Bear Run Nature Reserve,
offer a different type of forest. So just conducting conservation work in northcentral Pennsylvania is not going to capture the species and unique associations found in these mountains and at Bear Run.

The mountainous topography of the reserve is distinctive as well, with long views of the Youghiogheny Valley, massive blocks of sandstone tumbled along the slopes, and streams dropping down from their headwaters, bubbling over rocks and through thick
rhododendron.

Scars from coal mining and its related industries are still visible throughout southwestern Pennsylvania. At Bear Run, thanks to the careful consideration given the site, first by the Kaufmanns, then by WPC, most small underground mines have been closed up, and
timbering has been suspended, allowing the forests to grow and age. Further restoration is under discussion for any remaining mines. Its interesting to remember that the areas where the public spends much of its time exploring were very much developed at the
beginning of the last century, Wagner said. Upslope of The Barn at Fallingwater, near the beginning of the Arbutus Trail, there was a homestead and a farm. All of that area was cleared. To walk it today is to experience an encouraging example that forests do come back.

More than 20 miles of marked trails traverse the Bear Run Nature Reserve and join many miles of other regional trails. All are open to the public to explore. The grounds of Fallingwater are part of the reserve and the world-famous Frank Lloyd Wright structure is
intimately a part of Bear Run itself as the stream passes directly under the house.