The Lake Erie Allegheny Partnership (LEAP), a local coalition of parks and natural areas, is coming to terms with how the region’s forests will look in a significantly warmer climate. Cleveland is likely to experience hotter, drier summers and warmer, shorter winters this century, a regime change that is expected to push trees that thrive in our current moderate, wet climate to their limit.
A new US Forestry Service (USFS) climate vulnerability assessment looks at how the habitat for Northeast Ohio’s iconic trees—sugar maples, pin oaks, hemlock and beech — will be pushed north, while the climate that is likely to replace it will support tree species that are commonly found in Southern Ohio and the lower Midwest such as Mockernut Hickory, Eastern Red Cedar, Chinkapin oak and other drought resistant species.
Tapping the latest data on annual temperature and precipitation and projecting a four and a half degree Fahrenheit increase will change the suitable habitat for half of Northeast Ohio’s current tree species to low adaptive capacity. Red, Sugar and Silver Maple tree populations will likely experience the greatest decline. But maples will still be present because of how abundant they are in our area. Still, 50 years from now, drives out to the country to catch the glorious fall colors will be duller, and the spring sugar maple festivals could be a thing of the past.
The latest USFS model used 40 variables like temperature, precipitation, soil type, and topography to produce a map of suitable habitat under both 4.5 degree F and 8.5 degree F climate change scenarios.
“It is a filter (for forest managers) to make their plans,” says USFS principal investigator Louis Iverson, who presented the data to LEAP.
When asked about how factors, like the structure of the ecosystem, will bear on tree adaptation, Iverson said small scale arrangements will definitely need to be applied to decisions on which trees to plant or tend.
LEAP also heard about climate adaptation strategies from Patricia Leopold of the Northern Institute of Applied Climate Science (NIACC). The lead author of Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers, Leopold discussed how to put the latest data from USFS into context. Her organization has devised three standards for climate adaptation strategies: Resistance, Resilience, and Transition.
Resistance, as the word suggests, would have a forest manager ride out climate change and hope for the best. Resilience makes small modifications to deflect and absorb climate change. “It’s going to happen," she said, "for example, gypsy moths could defoliate your forest canopy and change the conditions of the understory.” Transition is actively promoting species change by, for example, replacing species not projected to fare well.
Forest and natural areas resource managers don’t need to overreact, she said, but attenuate their strategies with goals like enhance genetic diversity and re align after disturbances like the gypsy moth example. With the dawn of climate change, comes a more sobering assessment for natural areas managers—that a hybrid, not a utopian, vision is needed to steer their actions.
“We can restore the function of an ecosystem and allow it to cope with climate change," Leopold said. "But there is no perfect state to return to. We might de emphasize sugar maples and change the species mix over time.
"One of the strengths of LEAP is coming to agreement on big strategies, to respond and connect the dots.”