Published April 14, 2025
Understanding MetroParks’ impact with soil science
In 2023, Five Rivers MetroParks conducted a comprehensive study on soil carbon sequestration across its diverse ecosystems, including prairies, forests and wetlands. Carbon sequestration – the process of capturing and storing CO2 – is integral in reducing the amount of greenhouse glass emissions and limiting climate change.
“As a conservation leader in our region, it’s important we understand our impacts when it comes to carbon sequestration, as we aspire to be a carbon-neutral agency,” said Five Rivers MetroParks biologist Lisa Hill. “Because there are not many soil carbon studies in the Midwest – or even the U.S. – to compare, this wasn’t something we could just research online. We had to get more comparable information.”
The goal of this study was to assess carbon sequestration of MetroParks’ natural habitats across the agency.
MetroParks’ conservation team – along with the scientists from Eco Logic – collected soil samples from 10 MetroParks at over 54 random points in 11 different habitat categories. In addition to the physical soil samples, measurements and recordings were taken of the species, sizes and canopies of the different trees in each habitat, along with what plant communities and logs were on the ground.
Soil samples were sent to a research facility in the winter of 2023. After the chemical analysis of the samples, Eco Logic sent MetroParks’ conservation team the raw data set of the soil sample assessment. Next, MetroParks staff, including Lisa Hill (biologist), Amy Forsthoefel (manager, research and analysis), Grace Dietsch (director of conservation) and Kelly Bohrer (sustainability manager), gathered to analyze the data the following spring.
With calculations from Crown et al. 2023 we estimated tree and soil carbon stock, and annual live tree sequestration rates.
Figure 1. Carbon stock density (tons of carbon per acre) of soil, standing dead trees, and live trees across Five Rivers MetroParks habitat communities in Ohio.
After, Hill mapped these habitats to calculate total acres, which established estimates of carbon storage and sequestration by habitat, by park and agency wide.
Figure 2. Estimate annual sequestration (tons of carbon) from live stems across Five Rivers MetroParks owned and leased land in Ohio.
The results tell a story of why MetroParks’ reforestation efforts are so important in the quest to mitigate climate change.
Results:
- All of MetroParks’ live trees estimate to sequester 46,500 tons of carbon per year, removing 172,223 tons of carbon dioxide. According to EPA Greenhouse Energy Calculator this is equivalent to:
- 36,079 gasoline-powered vehicles driven for one year
- 20,772 homes energy use for one year
- 46.2 wind turbines running for one year
- MetroParks’ forest, prairie, and wetland habitats estimate to store 808,369 tons of carbon in the soil – enough to fill 161 Olympic swimming pools.
- One acre of MetroParks’ forest cycles 23 tons of carbon annually, which is equivalent to the average energy use of 10.3 houses or 17.8 gasoline-powered vehicles driven for one year.
- Germantown MetroPark accounts for 20% of MetroParks’ total carbon stored and sequestered due to its extensive forest habitats.
- Invasive shrubs are much smaller than native trees, and in the long-term do not sequester as much carbon and can choke out native trees from growing to their full potential. It is important to reduce invasive species densities to promote succession of native forest communities. Learn more.
“We have found the positive effects of MetroParks’ habitats are invaluable for the environment and the public,” said Hill. “These ecosystems provide cleaner air and water, prevent erosion and are impactful in reducing the amount of CO2 in the air which is warming our planet. The findings from this study are pivotal for prioritizing restoration efforts, shaping land conservation strategies and fostering public understanding and engagement in conservation practices.”
Indeed, planting trees – especially native species – can have an impressive impact on the environment. In fact, all the turf grass in MetroParks cycles less carbon than just one acre of forest habitat.
“This could have big implications for homeowners, too,” said Hill. “People can offset their own carbon footprints by planting trees and other native plants on their properties and reimagining the standard turf lawn. Other ways to reduce your carbon footprint include reducing waste, conserving water, reducing consumption of single use items, shopping sustainably, biking or walking instead of driving when applicable.”
THE LOW DOWN ON CARBON
To understand what carbon sequestration means we need to review the role of carbon.
There are two major types of carbon: organic and inorganic. Organic carbon is primarily derived from plants through photosynthesis and found in living organisms. Inorganic carbon is not a part of living or decomposing organisms, such as carbon dioxide, carbon monoxide, and carbonate rocks.
Carbon sequestration is the removal and storage of carbon dioxide from the atmosphere. Carbon itself is not “bad,” but excessive carbon dioxide (CO2) in the atmosphere acts as a greenhouse gas that traps heat, thus high levels of atmospheric carbon accelerate climate change.
BUILD YOUR GREEN VOCAB
- CO2 is a greenhouse gas, which traps heat in the atmosphere like a blanket over the Earth, warming our planet and causing climate change.
- Carbon cycling is the natural process in which carbon moves through the atmosphere, plants, animals and more.
- Carbon is deposited in the earth when living things die and decay, such as plants and animals.
