We’re home to over 3,500 acres, approximately 3,100 of which are classified as natural areas.
Wetlands, streams, rivers, ponds and lakes
Learn the answers to the questions we’re asked most.
Biodiversity is the variety and variability among native living organisms and the natural ecosystems in which they occur.
We think of biodiversity at three main levels:
- The landscape or ecosystems level
- The variety and different organisms within the landscape
- The genetic diversity within any given species
Within our natural areas, hundreds of plants, animals, insects and birds co-exist and collaborate to create the diverse landscape we call The Holden Arboretum.
Active natural area management includes any activity designed to remove or minimize negative influences on an ecosystem to the extent possible. It includes, but is not limited to, removing invasive plant species, invasive pests and pathogens, and white-tailed deer.
Natural Areas management also includes any activity taken to optimize habitat to promote the reproductive success of our native plant or animal species.
The Holden Arboretum is a living museum, and plants create a number of the vertical niches that are available and utilized in their communities.
Vertical niches exist within all the layers of vegetation that naturally occur within plant communities. A great diversity of species inhabit and utilize the available vertical niches for nesting, food or cover. The greater the number of vertical niches, the greater the natural biodiversity.
The Holden Arboretum is organized into 14 natural areas, where you’ll find a range of plant communities, including:
Holden forest remnants range from the relatively common beech-maple forest in Bole Woods and the Woodland Trail to less common forest types, like the white pine-hemlock-northern hardwood forest on Little Mountain.
Holden meadows are agricultural remnants, but many have been managed as meadows for the past 75 or 100 years. Common field nesting birds such as the red-wing blackbird nest in these fields, but we also see rare bird species like eastern meadowlarks and bobolinks. Likewise, our meadows have native and non-native plant species, plus a mix common and rare native plant species.
The topography of The Holden Arboretum owes a great deal to water and gravity. These elements combine to create numerous perennial and intermittent streams, like the Pierson Creek Valley and Stebbins Gulch, and unique ecosystems such as Brainard Fen.
Holden also has 52 acres of ponds, which range from well-managed examples, like Corning Lake, to purely aesthetic ponds, such as Heath Pond in the Helen S. Layer Rhododendron Garden.
The Holden Arboretum is situated in the glaciated Allegheny Plateau and has numerous streams and tributaries feeding into the East Branch of the Chagrin River. As streams begin to cut through the glacial tills of the upland, numerous ravines develop and dissect the upland, creating a wide variety of microclimates that support a greater diversity of plant and animal species.
Bedrock geology has also created some unique landforms, such as Little Mountain and Stebbins Gulch. There’s approximately a 435-foot change in elevation between Holden’s highest point (on Little Mountain) and our lowest point (on the East Branch of the Chagrin River).
The East Branch of the Chagrin River is a designated State Scenic river, and more than 5.5 miles of this river flows through The Holden Arboretum. The Pierson Creek Valley, Stebbins Gulch, and the Shady Brook are important watersheds that all feed into the East Branch and help maintain its cold-water habitat and high water quality.
National Natural Landmarks
In 1967, Holden Natural Areas were dedicatedby then Secretary of the Interior Morris Udal as National Natural Landmarks.
The National Natural Landmarks Program recognizes and encourages the conservation of outstanding examples of our country’s natural history. It’s the only national program that identifies and recognizes the best examples of biological and geological features in both public and private ownership.
To date, fewer than 600 sites have been designated.