How Much Carbon Can 170 Acres of Trees in Ohio Store?

Written by Bill Stanley on . Posted in Act, Learn

I recently heard about a really cool story from the Ohio town of Avon Lake, a small Lake Erie town west of Cleveland, where folks were able to save about 170 acres of woods (maples and oaks) from being cut down and developed. It was a grassroots citizen-led campaign they called “Save the Woods.” The group then donated the land to the local parks system.

One of the individuals who participated in that effort wrote to us with a simple enough question about the potential benefits the trees would have in terms of carbon dioxide emissions: “I wonder what the small efforts of saving trees mean? Can anyone estimate the effect of keeping 170 acres of trees?”

So, as the conservation director of The Nature Conservancy in Ohio, a forest scientist and a guy who’s studied (and hugged) his fair share of trees (come on, what’s not to love?), I put myself on the job of providing an answer.

I wanted to share my response so that other communities can learn from Avon Lake’s great example.

This was my response*:

Hey, thanks for asking! I think all of us learned at some point that plants do this wonderful thing called photosynthesis. Trees absorb carbon dioxide and convert it into solid carbon in the form of leaves, bark, wood and roots, as the trees grow. Unfortunately, once a tree is cut down and burned or left to decay, this solid carbon is broken down and released into the atmosphere as carbon dioxide gas. In fact, about 15 percent of annual global greenhouse gas emissions are from deforestation. That’s more carbon pollution per year than all the planes, trains and automobiles combined.

So, to get to your question, 170 acres of woods can capture and store a surprisingly large amount of carbon. How much depends quite a bit on the composition, age and quality of the forest.

First, I will assume that the forest is around 55 years of age (probably a decent guess for your area) and well stocked (meaning not a lot of harvesting has occurred). Since the answer will also vary depending on whether Oak or Maple is the dominant species, I will give you an estimate for both.

At 55 years, 170 acres of well-stocked Oak/Hickory forest in your region contains about 41 thousand metric tons of carbon dioxide, while a similar Maple/Beech forest would contain about 28 thousand metric tons of carbon dioxide. So, a middle of the road estimate may be around 35 thousand metric tons of carbon dioxide. For context, on average, cars emit around 5 tons of carbon dioxide per year. So your 170-acre tract has pulled in the emissions of almost 130 cars per year, over the last 55 years. Not bad.

To do this quick estimate I had to make some other fair assumptions. For example, I didn’t even consider the likelihood that the amount of carbon preserved in the soil increased over time, which would have made the carbon savings even higher. On the other hand, I also assumed the forest would have been completely developed (e.g. into a strip mall rather than a development where some trees are left standing), and that no wood was harvested and made into long-term wood products (e.g. furniture) where the carbon would have remained out of the air for a long time. Even so, taking whatever your situation might be into account, we would still find that your work to protect the forest has helped quite a bit.

Another positive thing to remember is that a forest left standing continues to grow, while an area converted to development doesn’t. As such, in another 30 years, the forest would have grown and captured something like 9,000 metric tons more of carbon dioxide. While your forest will grow more slowly as it ages, it will still be doing its thing for the planet.

You might also be interested to know that The Nature Conservancy has been working on a forest conservation project of roughly twice the size of your town’s example, down in the Lower Mississippi Valley in Louisiana. It’s called the Tensas River Climate Action Project and you can read about it, and our full online carbon footprint offset program, here.

*Calculations based on “Evaluation Tool for Reforestation- and Afforestation-based Carbon Sequestration Projects in the United States,” developed in 2006 by The Nature Conservancy and WestWater Research, LLC, and funded by a generous grant from the Department of Energy.

Bill Stanley is the conservation director of The Nature Conservancy in Ohio.

Photo by: Ian Adams (Ohio woods)

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