Conservation

The Holden Arboretum owns over 3,600 acreas, which includes the recent Roudebush parcel purchase of 90 acres. Of that, approximately 3,100 acres are natural areas. Approximately 85 percent of Holden’s natural areas are woodland; 12 percent meadows; and the remaining three percent are wetlands, streams, rivers, ponds and lakes. 

 

The Holden Arboretum is blessed with abundant natural resources, which range from the unique land itself to the hundreds of native plant, animal and insect species that live within these lands. In June 2006, The Holden Arboretum adopted a strategic plan for conservation in order to establish goals and outline the types of active management that would take place in Holden natural areas.

 

Manage Holden natural areas for the purpose of sustaining or increasing current levels of native biodiversity, with an emphasis on plants.

 

What is native biodiversity? 

 

In general terms, biodiversity is the variety and variability among native living organisms and the natural ecosystems in which they occur. Biodiversity encompasses the differences between and within; ecosystems, genera, and the genetic or molecular diversity of any species. Holden’s natural areas hundreds of plant, animal, insect and bird species co-exist and combine to create the diverse landscape we call The Holden Arboretum.

 

 

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.

What is natural areas management? 

 

Active natural area management includes any activity designed to remove or retard negative influences on an ecosystem to the extent possible, including but not limited to, the impact caused by invasive plant species, invasive pests and pathogens, and white-tailed deer.

• Mowing a meadow to slow natural succession and the invasion by woody plants.

• Removing an invasive species such as garlic mustard from Holden woodlands.

• Fencing individual plants or large natural areas to prevent white-tail deer browse.

View the map of Holden's Natural Areas

Natural Areas management also includes any activity taken to optimize habitat to promote the reproductive success of our native plant or animal species such as: 

• Removing competing vegetation to allow more sun reach a plant and allow it to flower.

• Delaying mowing meadows until the animal, bird and insect species completes their life cycle of egg to adult; or a specific plant species completes their life cycle of flower to seed.

• Providing nesting boxes for the Eastern Bluebird and continued monitoring by Holden’s volunteer Bluebird program.

Why an emphasis on plants?

 

The Holden Arboretum is all about plants with a special emphasis on woody plants. Staff expertise is plants. Plants create the number of vertical niches available and utilized in the plant community. 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 utilized, the greater the natural biodiversity.

 

Ecological Restoration

 

Ecosystems and plant communities can lose parts of their ecosystem function when important components of ecosystem function are lost. To complete the natural areas management loop it may be necessary, based upon the best scientific data, to restore degraded ecosystems by:

• Re-establishing plant layers, age classes of plants or species composition within Holden natural areas to provide forest interior birds a place to nest.

• Restoring cold-water habitat within streams by removing impediments to flow.

• Restoring depth to a vernal pool so that sufficient water depth persists long enough for amphibians to complete their life cycle.

View the Plant Communities of Holden

 

Forest remnants

 

Holden forest remnants range from our relatively common beech-maple forest we see in Bole Woods and the Woodland Trail to the less common forest type, the white pine-hemlock-northern hardwood forest on Little Mountain. 

 

Meadows

 

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, as well as rare bird species such as the eastern meadowlark and the bobolink. Likewise our meadows have native and non-native plant species and common and rare native plant species.

 

Wetlands

 

The topography of The Holden Arboretum owes a great deal to water and gravity. These two elements combine to create numerous perennial and intermittent streams, the Pierson Creek Valley, Stebbins Gulch, and unique ecosystems such as Brainard Fen. Holden also has 52 acres of ponds, which range from well-managed examples such as Corning Lake to purely aesthetic ponds like Heath Pond in the Helen S. Layer Rhododendron Garden.

 

Topography

 

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 are support a greater diversity of plant and animal species. A walk through the Pierson Creek Valley allows one many opportunities to see young and old valleys formed by large and small tributaries to Pierson Creek.

 

Bedrock geology has likewise created some unique landforms such as Little Mountain and Stebbins Gulch. Vertically there is an approximately 435 foot elevation change between Holden’s highest point on Little Mountain to the lowest point on the East Branch of the Chagrin River.

 

Watersheds

 

The East Branch of the Chagrin River is a designated State Scenic river and more than 5.5 miles of the river flows through The Holden Arboretum. The Pierson Creek Valley, Stebbins Gulch, and the Shady Brook are important watersheds that feed into the East Branch and help protect and maintain its cold water habitat and high water quality.

 

Land Protection

 

Holden owns over 3,600 acres, but it is impossible on many levels to own all the land necessary to protect the great regional biodiversity that creates the landscape we think of as The Holden Arboretum. In 1992, The Holden Arboretum started a conservation easement program in order to work with our neighbors to protect local watersheds and expand the protection of Holden’s significant natural areas by land conservation on private or public properties. Holden currently holds conservation easements on 21 properties that total approximately 1,400 acres.

 

What is a Conservation Easement?

 

A conservation easement is a specialized interest in land that restricts the owner’s use of property in specified ways and designates the holder of the easement with enforcement responsibilities. Its purpose is to protect the natural, scenic or historic values of the property.  A conservation easement is granted in perpetuity and will apply to all future owners.            

 

Holden Natural Areas

 

For the sake of management purposes, The Holden Arboretum has been organized into 14 natural areas. Some of these natural areas are well known, such as Pierson Creek Valley, Bole Woods, Carver’s Pond, Little Mountain, and Stebbins’ Gulch; and others are less well known and visited. Some of Holden natural areas are open to the public while others are closed to the public and accessible only with a guide or permit. In the future, a goal is to provide more guests more opportunities to visit Holden natural areas without putting people or these natural areas at risk.

 

View the map of Holden's Natural Areas

 

 

Natural Areas open to the public

• Holden Meadows – These areas are managed to maintain and present important horticultural collections, scenic vistas and biologically diverse meadows.

• Bole Woods – A National Natural Landmark with a mature Beech-Maple Forest remnant that is a unique discovery opportunity and visitor destination where horticultural collections and natural areas meet.

• Strong Acres – An attractive destination for exploration and discovery of meadow and forest diversity, and a site for future grassland restoration.

• Fisherman’s Ponds – A serene and secluded landscape providing opportunities to study wetland habitats and the convergence of land and water at the headwaters of Pierson Creek.

• Pierson Creek Valley –  A woodland with a creek in the heart of Holden, offering opportunities for leisurely or challenging hikes, natural playgrounds, deep scenery, and quiet birding.

• Sugarbush – Holden’s Sugarbush is a Beech-Maple forest remnant that was managed for Maple Syrup production for over 30 years.

Natural Areas open on a limited basis on Guided Hikes

• Carver’s Pond – This wetland complex is an extraordinary conservation destination, offering opportunities for research, stewardship, and rigorous guided hikes.

• Baldwin Natural Area – Provides an opportunity for remote hiking with connection to the scenic river corridor, Baldwin’s diverse forest, and Carver’s Pond. Shadybrook provides cold water habitat and the opportunity for stream restoration.

•  Little Mountain – To an extraordinary visitor destination for the interpretation of the convergence of geology and natural history, and the interaction of nature and culture. This is also to be an opportunity for research on this locally rare ecosystem. Little Mountain is one of the best remaining examples of White Pine-Hemlock-Northern Hardwood forest remaining in Ohio.

• Stebbins Gulch, North –  A National Natural Landmark that is an excellent example of a NE Ohio bedrock ravine system. Guided hikes provide a rigorous and rare natural and geologic history experience in a cold water stream ravine. Along the bluffs of Stebbins Gulch is one of the best remaining hemlock-northern hardwood forest remnants in Ohio.

• Stebbins Gulch, South – This 800-acre natural area is Holden’s largest unbroken mature forest and protects the associated diversity of flora and fauna of an old-growth forest. Access is limited to stewardship, research or guided hikes.

• Brainard Fen –  This unique wetland is a high quality example of a rare ecosystem with very limited access for stewardship and research. 

• East Branch Chagrin River Corridor – More than 5.5 miles of this state-designated Scenic River flows through The Holden Arboretum and provides access to explore and discover the beauty of the river’s habitat.

• Corning Woods – A 17-acre remnant of a mature mixed oak forest that clearly demonstrates the effect of land use upon forest succession.

 

The Holden Arboretum was dedicated as an IBA on June 18, 2004.

 

What is an Important Bird Area?  An IBA is an international designation and recognition by Audubon Ohio, as partners with Bird Life International and the North American Bird Conservation Initiative, which identifies those places that are critical to birds during some part of their life cycle – i.e.: during breeding, wintering, feeding, or migrating. The IBA program was first started by Bird Life International in Europe and Africa in the mid-1980s. Audubon launched state-based IBA programs in the United States in 1995. Audubon Ohio started identification of IBA in Ohio in 2000. Holden is one of more than 100 IBA focus areas in Ohio and is part of the Chagrin River Corridor IBA, one of over 50 regional IBA sites in Ohio. What are the criteria for being an IBA?

• Places where rare species of birds are found. 

• Places with rare natural habitats with birds that are only found in these special habitats.

• Places where large numbers are found.

• Places that have been important for a long time for the study of birds.

 

The Holden Arboretum has long been known as an area where there are many birds. To put Holden’s birds into perspective; 412 bird species make up the state of Ohio’s total bird list and 218 have been identified at The Holden Arboretum. More than 150 bird species have been identified as breeding in the greater Cleveland region and 93 of these species are confirmed breeders at The Holden Arboretum. In other words, during spring migrations, a birder with sharp eyes and ears has the opportunity to see more than one-half of the bird species which occur in Ohio and during the summer breeding season, more than one-half the birds which nest in the greater Cleveland area. Holden is a great place for birds.

 

In terms of rare bird species, of the 93 confirmed breeding bird species, four are state-endangered species and 13 additional species listed as “special interest” or “high priority” by U.S. Fish and Wildlife Service because of significant population declines.

 

 

In terms of being a places with rare natural habitats with birds that are only found in these special habitats, Holden is very fortunate to have the old growth forests such as Bole and Corning woods; the specialized microclimates such as the hemlock-northern hardwoods forest remnants in Pierson Creek, Stebbins Gulch and Little Mountain. Examples of rare bird species that have specific habitat types such as old growth forests or hemlock ravines include: winter wren, magnolia wWarbler, cerulean warbler, Canada warbler, and dark-eyed junco. Examples of rare bird species that require large blocks of contiguous habitat forests such as the unbroken block of 800 acres in Stebbins Gulch or the meadows of Strong Acres include wood thrush (forest) and eastern meadowlark and bobolink (meadow).

National Natural Landmarks

Holden Natural Areas were dedicated in 1967 by then Secretary of the Interior Morris Udall, as National Natural Landmarks. The National Natural Landmarks Program recognizes and encourages the conservation of outstanding examples of our country's natural history. It is the only natural areas program of national scope that identifies and recognizes the best examples of biological and geological features in both public and private ownership. National Natural Landmarks are designated by the Secretary of the Interior, with the owner's concurrence. To date, fewer than 600 sites have been designated. The National Park Service administers the National Natural Landmark Program.

Natural Area threats

Natural Areas through Northeastern Ohio are faced by a wide variety of threats. These threats include urban development pressures, edge effect, invasive plant species, feral animals, white-tail deer browse, earthworms, introduced diseases, and insects and climate change.

Invasive Plant species

Any plant that grows outside of its natural range is considered exotic. If it responds to its new environment with rapid 

growth, and if it can quickly establish itself over large areas of land then it is considered invasive.

How does this happen?

When humans were introduced into North America we brought plants with us from our country of origins. Plants have

been introduced for agricultural purposes, horticultural purposes, and in some cases, purely by accident. However, when

a plant species is introduced outside its natural range, it is also outside the natural range of its natural controls that can

include any herbivores, parasites and diseases. Free from these natural controls, some exotic plants experience rapid

and unrestricted growth, become invasive in their new environments, and reduce ecosystem diversity and function.

Why aren't’t all exotic plant species invasive?

The primary factors which contribute to a plant’s ability to invade include its life cycle, annual or perennial; how it

spreads, as a vine or by seed;  its capacity for abundant seed production; its high seed germination rate; how long-lived

its seeds are; and how rapid it can mature to its seed-producing stage. The quicker it can reproduce itself, the quicker it

can invade and overwhelm the native plant species which previously occupied the land.

Why do we care?

Invasive plant species are the second greatest threats to the natural ecosystems of the world today. Only direct habitat

destruction poses a greater threat to the future of biological diversity. Invasive species disrupt the ecology of natural

ecosystems by displacing native plant and animal species and reduce biological diversity by reducing the amount of light,

water, nutrients and space available to native species.

What Plants are Invasive in Northeastern Ohio?

 

 

 

For more Information:

• Ohio Invasive Plant Council 
• Midwest Invasive Plant Network
• Plant Conservation Alliance

Invasive Insects and Diseases

The introduction of exotic plant species have resulted in the escape of plant pathogens which have greatly impacted our local flora, such as Dutch Elm Disease, Beech Bark Disease, Chestnut Blight and Dogwood Anthracnose. Introduced insects that have impacted Holden include European Beech Scale, Gypsy Moth and Emerald Ash Borer.

Introduced Animals

White-tail Deer were extirpated from Ohio in the late 1800s but were re-introduced to Ohio in the late 1920s. Browsing by white-tail deer has a negative impact on all Holden collections. Deer browse destroys specimens propagated or purchased for the designed landscape. Browsing severely limits ecological function of natural areas when whole age classes and layers of woody species disappear from the landscape. Holden has protected a landscape matrix of woodland and grassland that is coincidentally optimal habitat for whitetail deer. Deer exclosure studies within the natural landscape produce quantifiable data on the impact of whitetail deer on the landscape. Infrared aerial surveys document the population density of whitetail deer in and around the Holden landscape. Historical density for whitetail deer in northeastern Ohio is eight deer per square mile. Current whitetail deer density is 29 deer per square mile. Whitetail deer are one of the strongest negative pressures on Holden landscape and require management plans to reduce population density.

Earthworms

Did you know that there are no native earthworms in glaciated North America?  For many of the same reasons that earthworms are useful in a vegetable garden, they are harmful within our native woodlands that evolved with earthworms. Studies conducted by the University of Minnesota show that at least seven species of earthworms are invading Minnesota’s hardwood forests and causing the loss of tree seedlings, wildflowers, and ferns. Invading earthworms eat the leaves that create the duff layer and are capable of eliminating it completely. Big trees survive, but many young seedlings perish, along with many ferns and wildflowers. In areas heavily infested by earthworms, soil erosion and leaching of nutrients may reduce the productivity of forests and ultimately degrade fish habitat. For more information on invasive earthworms visit the Minnesota Department of Natural Resources web site.

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