One of the largest botanical gardens in the United States, the Holden Arboretum opened to the public in 1937. Located just a few miles from the banks of Lake Erie in Kirtland, Ohio, this 3,500-acre ecological museum comprises a patchwork of old-growth forests, young post-agriculture forests, and wetlands combined with more than 200 acres of cultivated gardens showcasing an immense diversity of plants from around the region and the world. Now, the acceleration of global warming has begun to cause dramatic shifts in the arboretum’s ecology. With climate change already beginning to adversely affect its natural areas and plant collections, the arboretum is acting as a laboratory to develop climate-hardy, disease-resistant species that will help create more resilient landscapes for a warming planet.
Modeled on Harvard University’s Arnold Arboretum and begun in 1931, the Holden Arboretum was established on 100 acres of land donated by mining magnate Albert ’Bert’ Fairchild Holden, who sought to create a living memorial to his deceased wife and daughter. Holden grew up on a family estate in Bratenahl, Ohio, where he showed an early interest in botany by building greenhouses, cataloging plants, and visiting the famed Kew Gardens in England. Educated as a mining engineer at Harvard, Holden immediately began working for his father’s mining business in the silver fields of Utah after graduation in 1888. After purchasing many of his father’s mines, he consolidated his interests under the banner of the United States Mining Company. Between 1901 and 1906, the operations had expanded to include dealings in gold, silver, lead, and copper, and Holden had established one of the largest mining and smelting organizations in the world.
Following a series of personal tragedies, including the deaths of his wife Katherine in 1900 and one of his three daughters, Elizabeth, in 1908, Holden laid the foundation for the arboretum. After first entertaining the idea of converting his family estate into a memorial arboretum, he decided to purchase 50 acres at Cleveland’s Lake View Cemetery to establish the new Elizabeth Davis Holden Memorial Arboretum, for which a site plan by the Olmsted Brothers firm was commissioned. But Holden’s sister, Roberta Holden Bole, was uncomfortable with the prospect of a cemetery arboretum and instead urged her brother to create a “living” memorial to his wife and daughter. After Albert Holden’s death in 1913, it was she who managed the family trust and who was instrumental in realizing the institution.
The project was cemented in 1929 when the Bole family offered a 100-acre site in Kirtland, Ohio, with an ideal microclimate that especially suited the project. C. Gordon Cooper was to design the arboretum, which from early on was conceived as a museum of forest types, recreating flora and diverse ecosystems from around the world. Embracing the dual mission of academic research and archival documentation, the arboretum rapidly expanded in size, benefitting from several large donations of land from the surrounding estates. Initially under the management of the Cleveland Museum of Natural History, which Holden’s mother had a hand in founding, the arboretum was opened to the public in 1937. It was during this early period that a 556-acre parcel of the Baldwin Farm, which now hosts the arboretum’s nut-bearing tree collections, was acquired. With the support of benefactors such as investor Warren Corning, the arboretum expanded to 1,000 acres in 1956, then parting ways with the museum. In 2014 the arboretum was integrated with the Cleveland Botanical Garden, a 101-acre urban landscape, to form Holden Forests & Gardens.
Currently the arboretum encompasses a sprawling 3,500 acres. Shaped over the decades by landscape architects William A. Strong, Geoff Rausch, Melissa Marshall, and Donald Gray, this irregularly shaped site with undefined boundaries is bisected by Sperry Road and roughly stretches from Pierson Creek in the west to Wisner Road in the east. A looped offshoot from Sperry Road, in the northern section of the site, leads to the Corning Visitor Center and a contiguous parking lot. The Corning Lake (ca.1938) is located in the southeastern swath of the site, and several smaller bodies of water are scattered throughout. These include Foster Pond to the north, Blueberry and Buttonbush Bog to the west, and Sherwin, Heath and Hourglass Ponds to the south.
The arboretum is home to a collection of more than 10,000 woody plants, encompassing some 1,700 species, thus representing much of Earth’s woody biodiversity. These collections conserve genetic information both across and within species, providing an important resource for research and public outreach. Beyond these managed collections, the arboretum also conserves critical forests and wetlands, providing a habitat for wildlife and improving water quality in local streams and, ultimately, Lake Erie. The woodlands are crisscrossed by meandering trails, picnic grounds, and discreet gardens that feature specific ecosystems, such as the Crabapple Collection, the Holden Butterfly Garden, the Layer Rhododendron Garden, and others. Since 2004 the arboretum has also been designated as an Important Bird Area by the National Audubon Society, providing critical habitat for forest-interior bird species. The property is home to 25 Ohio rare plant species, including the autumn willow and the round-leaf sundew.
According to 100 years of climatic data and present climate-change models, by the end of this century, temperatures in this region of Ohio could rise from seven to twelve degrees Fahrenheit during winter months, and from six to fourteen degrees Fahrenheit during summer. Extreme heat events and regional droughts will become more common, affecting Ohio’s vast agrarian economy, reducing land productivity, fish stocks in Lake Erie, and sources of drinking water.
"What are the dangers of climate change? It threatens the basic ecosystem functions that plants provide. Plants are the base of the food pyramid for all terrestrial and most marine ecosystems upon which we and all other animals depend. "
Brian Parsons, Director of Planning and Special Projects, Holden Arboretum
The increasing unpredictability of the climate threatens both the arboretum’s collections and its natural areas. Soaring temperatures and shifting patterns of precipitation have already added stress to certain species, causing their decline. Emerging pests that thrive in the changing environment have directly caused dramatic shifts in the ecosystems. These include invasive species like emerald ash borer and hemlock wooly adelgid. In parallel with these threats, diseases such as phytophthora root rot and a yet-to-be-identified beech leaf disease are rapidly and dramatically reshaping Holden’s forested areas, decimating once-dominant tree species like ash, beech, and hemlock while simultaneously altering the diversity and function of the forest systems. Amphibian populations are also expected to be affected by invasive pathogens, such as chytrid fungal disease, while bat populations are in decline because of white nose syndrome.
With these threats from the changing climate affecting such a broad array of its ecosystem, the Holden Arboretum and its collections serve as a de facto laboratory where the outcomes of climate change can be better tested and better predicted. For as the magnitude of climate variability increases, so do the effects on the arboretum’s natural and managed landscapes. Slow ecological changes resulting from warmer temperatures and more extreme patterns of precipitation have led to rapidly shifting phenologies. Phenologies are cyclic and seasonal patterns of natural phenomena, such as flowering—the events on nature’s calendar. Shifting phenologies can create mismatches among interacting insect, bird, and plant species, threatening them with population decline. Climate scientists have discovered that studying historic records of plant an animal phenologies provides an excellent window into the local effects of climate change (the detailed journals kept by Henry David Thoreau, for example, have been very valuable in that regard). The arboretum is thus already witnessing the adverse effects of climate change while being at the forefront of research to help mitigate those effects.
What You Can Do to Help
The Holden Arboretum is working to create healthy and resilient landscapes. The monitoring of its collections provides information on long-term responses of woody plants to chronic climate change. The creation and curation of research aimed at breeding new climate-hardy and disease-resistant genotypes of regionally important plant species plays an important role in developing the genetic diversity required to make our landscapes more resilient as the planet warms. The displays of woody plants are also a perfect platform for educating the public on the potential consequences of climate change, particularly through dedicated collections, such as the Climate Change Collection or the Rhododendron Discovery Garden.
The Working Woods is a newly developed research and demonstration site at the arboretum, serving to highlight and explain proper forest management practices while simultaneously acting as a living laboratory where scientists can quantify the impacts of land management on forest diversity and productivity, expressly in the context of a changing climate. On a national level, the public can learn more about the arboretum’s landscapes, both designed and natural, and donate funds to support its research and educational programs.