Tree canopy in Brown's Woodland nature area

Linking restoration to climate change mitigation

People, organizations, and corporations across the world are increasingly aware that advancing environmental and social action, especially with regard to climate change, requires ecological restoration. The Brown’s Woods Restoration and Oak Regeneration Project demonstrates this awareness by taking a rigorous science based approach to increasing carbon sequestration and biodiversity conservation through ecological restoration.

Led by Drake University and Polk County Conservation, this project received funding from the Microsoft and SER new standards-based ecological restoration collaboration. This program provides technical and field support to implement standards-based ecological restoration projects in communities hosting Microsoft datacenters across the world. Eight other projects across the United States and beyond have been funded to date.

About Brown’s Wood

Brown’s Woods is a 486-acre native woodland located in West Des Moines, Iowa (USA). It is one of the most heavily used parks in the metro area, seeing 178,000 visitors annually. It is also a key area that sequesters and stores carbon, making it an indispensable climate change mitigation resource.

Trails in Brown's Wood, Spring 2023

However, the Brown’s Woods nature area is under extreme pressure from invasive species and fast-growing shade-tolerant trees not typical to the ecology of the area. Though the area is sequestering carbon in its current state, restoring it to its native reference ecosystem, oak woodland, means increasing the overall net carbon sequestration capacity. When compared to softer-wood species, oak trees (Quercus sp.) have a greater net carbon sequestration capacity. For example, one silver maple tree will store, on average, 0.67 metric tons of carbon dioxide over its lifetime.  An oak, in contrast, will store 5.17 metric tons over its lifetime. Thus, restoring the forest to a more natural, oak-dominated community will result in substantial increases in carbon sequestration.

Why can’t oak trees grow?

The growth of the carbon dioxide loving oak tree in the urban forest is threatened by three ecological impairments: invasive understory plant species and vines, suppression of historic burn regimes, and subsequent changes in tree species composition throughout the area. These three impairments have led to a woodland made up of a dominant oak overstory and a dense and shady understory of invasive shrubs and shade-tolerant weedy tree species like hackberry, basswood, silver maple, and black cherry.

Dead fallen oak tree in Brown's Wood

As seedlings, oak trees grow better when they are exposed to sunlight. Because of the shady understory, therefore, acorns fail to germinate and oak seedlings struggle to get adequate sunlight for growth. Furthermore, a shady-understory favors the growth of those weedy shade-tolerant trees. Ultimately, when the dominant oak overstory dies, the existing large oak trees will be replaced by invasive plants and tree species not typical of a native oak woodland.

Learn more about trees and carbon sequestration here!

Going from some carbon sequestration to more

Restorative actions made possible through the Standards-based Restoration in Action program in collaboration with Microsoft will add to the ongoing restoration of oak woodlands in southwest Polk County. More specifically, the funds will help reverse the replacement of native oak woodland with other trees and invasive species through the following restorative actions:

1. Eradication of invasive species through techniques like cutting and mulching understory trees and invasive shrub species with a forestry mower. This will open up the understory, thus creating a habitat more favorable for oak germination.
2. Removal of standing trees in some areas to further increase the amount of sunlight that gets to the forest floor for improved oak seedling survival and growth.
3.  Hosting of volunteer planting events to reintroduce native understory and mid-story trees and shrubs, including oak saplings.

Overtime, the regeneration of oak species will lead to a net increase in the carbon stored relative to the current state. To measure the increase, Drake University students will build pre- and post-oak regeneration carbon budgets for the site. This allows Polk County Conservation and Drake University to monitor carbon accrual over longer time scales.

Stewards of Brown's Woods conducting invasive species removal

What makes this project standards-based ecological restoration?

By using the SER standards for this project, Drake University and Polk County Conservation have a greater chance of meeting their project goals. Standards-based ecological restoration helps account for complex ecosystem dynamics, navigate trade-offs in land use, address challenges, and increase design and implementation effectiveness.

The Brown’s Woods Restoration and Oak Regeneration project is designed to:

1. Draw on diverse and relevant knowledge and technical capacity by relying on and contributing data, and sharing management lessons with the existing professional network of state, county, and city staff. Additionally, experts at Iowa State University and the office of the state archeologist will consult with indigenous communities within the Brown’s Woods landscape.
2. Encourage the inclusion and participation of community members through rich volunteer opportunities as well as field trips to the site with high school students. This provides the community and youth in the area with opportunities to learn about ecological restoration, basic forestry, and plant identification techniques in the woods.
3. Identify and reduce direct and indirect causes of degradation. The combination of mechanized and volunteer removal of invasive plants plus volunteer oak tree planting will help reinstate and maintain the native oak woodland canopy community that is currently in the process of shifting to weedy shade-tolerant trees. In the future, the use of fire will help address the indirect causes of oak woodland habitat degradation by reducing understory cover and eliminating invasive species.
4. Increase integrity, area, number, or viability of biodiversity: in total, combining the anticipated gains in plant and animal species diversity, Brown’s Woods has the potential to go from an area with 150–200 species to one that sustains 300 or more species, including 3 to 4 endangered bat species.
5. Achieve and sustain the greatest net gain possible for environmental benefits, human wellbeing, and social equity for the community. Climate change mitigation is a key environmental gain for this project, as the growth of oak trees over time will substantially improve carbon storage in the forest.  Additionally, engaging with community volunteers and students creates a connection between stewardship of the land and personal growth and wellbeing. Finally, this project is already serving as a learning laboratory for diverse student and community groups, as a living demonstration as a living demonstration for creating a more sustainable future.

Drake University Student measuring tree diameters to build the pre-restoration carbon model

In all, when looking at the location of this work in combination with an area already managed by Polk County Conservation, a total of 100 acres of oak forest will be restored through this funding program. This project illustrates that standards-based ecological restoration offers great opportunities for climate change mitigation through carbon sequestration.

This project is being led by a long-time SER member and, SER Midwest-Great Lakes Chapter leader, Dr. Keith Summerville. 

Microsoft is proud to collaborate with Society and Ecological Restoration to deliver standards-based ecological restoration with the Drake University and Polk County Conservation in West Des Moines, Polk County, Iowa. Learn more here.