Biochar as a solution to wood processing waste

By Kathryn Reis

In August 2024, I joined the Randolph County Soil and Water Conservation District in North Carolina as a full-time environmental educator. I am a person who loves to research topics and share what I have learned with others, making this position a dream job for me in many ways. My current environmental education project aligns wonderfully with the Urban Wood Network: composting. 

Not all parts of a community tree can be processed into the functional desk at which I am currently working, or any other large product for home furnishing. When I attended the 2023 Urban Wood Academy meeting in Memphis, Tennessee, Jeff Carroll of the Urban Wood Economy said, “Urban wood is an opportunity, NOT an object.” 

And what were the opportunities that the Urban Wood Academy panelists mentioned? Job creation. Community relationship building. Partnerships with solid waste departments. Regenerative ecology. And public education.

Public education is the final piece to realize all of the opportunities that are linked to urban wood. As our society has become increasingly urbanized, people across all generations are forgetting the valuable role agricultural production plays in our lives. Sure, we know what the word “agriculture” means, but how many of us know the intricate ways in which agricultural producers must (1) work the land to grow our food and fiber commodities and (2) nurture the land to ensure it remains productive year after year? How many of us even focus on the various ways in which our human lives impact nature in urban, rural, and protected areas on a daily basis? 

Which brings me back to composting, especially a specific form known as biochar. Biochar production is an excellent way to transfer all of the urban wood waste that cannot be manufactured into a lumber-based commodity into something useful for agricultural producers, natural resource managers, and environmental specialists. Just like the compost derived from our food scraps, biochar can add nutrients to soil while maximizing water retention. But biochar can also do much more.  

Presently, the USDA U.S. Forest Service, USDA Agricultural Research Service, Environmental Protection Agency and their partners are exploring the multiple ways in which biochar can address soil health challenges in agricultural, forestry, and environmental management. Examples include soil amendment and water retention, soil remediation, soil pH balancing, carbon sequestration, and entrapment of metals and chemicals in surface runoff from agricultural fields and roadways. Visit the USDA Climate Hubs website to learn more. Biochar can be used for stormwater treatment and possibly as a substrate amendment for green roofs. 

As I stated earlier, I live in North Carolina; one state hit especially hard by Tropical Storm Helene. In Buncombe County alone, the NC Forest Service reported a loss of 40 percent of all trees. “In all, nearly 822,000 acres of forestland were damaged, and in some cases flattened entirely, throughout the 17 counties in western North Carolina impacted by the most powerful storm to hit the region in 35 years.” (Source: Asheville Watchdog)

These mind-boggling observations remind me of what Ashley Kite-Rowland (Urban & Community Forest Program Coordinator for Tennessee) said about storm debris at the Memphis Urban Wood Academy. The Tennessee Solid Waste Management Department requires the creation of a storm debris management plan for the entire state. The department’s goal is to identify the most efficient and cost-effective methods for (1) removing storm debris from roadways, yards, etc., (2) reducing the amount of waste entering landfills (all landfills have a lifespan!), and (3) determining where all waste is deposited within each county. Execution of such plans requires lots of money. Thus, storm debris management planners also have to identify funding sources for implementing their plans. Does your state have a storm debris management plan? If not, click here to learn more about Tennessee’s approach.

It is not uncommon for solid waste managers to burn unusable vegetative matter in an open setting. Open burns, however, generate particulate matter and vapor that harm human health. As an alternative, solid waste managers could use air curtain burners to keep a majority of the vegetative burn residue in a concealed chamber. The resulting residue is biochar. Air burners also burn vegetative matter 40 times faster than an open burn would while creating less CO₂ emissions. Click here to learn more about air curtain burners.

In sum, when only 30 to 40 percent of a felled urban tree can be diverted to a high-quality end use product (source: Mike Larrivee, Director of Sustainable Initiatives at The Works, Inc.), UWN members must explore how the remaining 60 to 70 percent of each felled tree can be used. Biochar is one such use.