Using pioneer records and aerial photos, two Baldwin Wallace University (BW) researchers recently chronicled centuries of decline in the size and diversity of forests in the so-called Forest City.

BW assistant professor of biology Kathryn M. Flinn, a plant ecologist, and undergraduate student Zachary R. Hughes in November published a study of changes in Cuyahoga County’s forests and tree canopy have changed with  “How a city shapes its forests: Land use change and forest distribution around Cleveland, Ohio over 220 years” in the Nov. 28 edition of the journal Urban Ecosystems.

The study looks at how urbanization—primarily the creation of buildings, yards, and farms has affected the region’s forest. The researchers used aerial photos of Cuyahoga County from 1938, 1979, and 2021 to analyze and interpret the impact.

Flinn and Hughes found that forested land plummeted from 98.7% before the pioneers to about 12% around 1900, then as farms were abandoned, began rebounding modestly to about 21% today, but with a narrower range of species than before.

Baldwin Wallace's Kathryn Flinn has documented centuries of decline in local forestsNot surprisingly, the study shows that Cuyahoga County’s typical forest today is small, averaging 44 acres, and 75% of those acres lie within 55 yards of the forests’ perimeters.

These fringes draw many invasive species, such as roses, privet, buckthorn, and other plants from our yards. And they don’t support as many native species as deeper woods do.

Cowbirds, for instance, lay eggs in other species’ nests in the fringes, and the baby cowbirds tend to hog the food there.

Farmers and builders play favorites with the land they choose to develop. They mostly raze flat, dry land instead of steep slopes or riverbanks. Locally, especially on the eastern side of Northeast Ohio, that means disproportionately reducing the stock of beech trees, which give nutrition, shelter, and shade to many species, including weasels, thrushes, woodpeckers, vireos, butterflies, frogs, and wildflowers.

Now beech trees are under attack by beech bark disease and beech leaf disease. The latter was first discovered in Lake County in 2012 and has quickly swept across the Northeast.

Cleveland’s not alone. Since the Ice Age, the world has lost about one-third of its forests. Nearly 20% of the remaining forest land lies within 109 yards of an edge.

Just 6.7% of Cuyahoga County’s landscape, or about one-third of its woods, are primary forestsAround 1800, Connecticut Land Company surveyors inventoried trees in much of the Western Reserve to identify promising lumber and soil.

Surveyor James Arbuckle wrote of one tract, “Land level and middling good; soil a sandy loam.”

The surveyors listed the 10 most common species of trees in different tracts. Flinn says the survey’s results are similar to those of latter-day vegetation studies.

For later data, the researchers analyzed aerial photos taken by the U.S. Department of Agriculture in 1938, 1979, and 2021. They counted any clump of trees big enough to make out from the photos as a forest.

In an interview, Flinn said from the photos, it was easy to recognize deciduous trees from conifers, and to tell the difference between regrown forests and primary ones (partly timbered but never cleared). The primary ones have taller and more irregular canopies.

Flinn says that farms don’t quickly revert to natural forests. Draining, plowing, tiling and fertilizing leave lingering damage. Farms abandoned by the Romans 2,000 years ago remain less diverse than primary forests.

Just 6.7% of Cuyahoga County’s landscape, or about one-third of its woods, are primary forests, says Flinn.

WRLC has planted saplings in many urban lots and preserved about 40,000 acres of forests“These forests are essentially irreplaceable on any human time scale,” she explains, calling for conservationists to focus on saving the forests and study how to help former farms recover.

Many local organizations are trying to reforest the region. The Western Reserve Land Conservancy (WRLC) has planted saplings in many urban lots and preserved about 40,000 acres of forests.

Pete McDonald, director of land stewardship with WRLC, says there’s great value to both efforts. “Different species need a certain size of forest and range that they can breed in and forage in,” he says.

Flinn is now planning a project with Constance Hausman, senior conservation science manager in the Natural Resources division of the Cleveland Metroparks.

The project will use Flinn’s maps to reveal the history of 400 study plots in the Metroparks and help determine conservation efforts. Hausman says the parks may also use Flinn’s maps in considering land to acquire.