Wren | Preventing wildfires while sequestering carbon with biochar

Just the gist

Short on time? Here’s what you need to know for this update.

Reducing wildfire risk with biochar

Rising global temperatures contribute to drier and hotter conditions, leading to more flammable forests. Research shows climate change has doubled the number of extreme-fire-weather days in the United States over the past 40 years. In Northern California’s forests, excess woody debris and dead material build up, creating dangerous fuel loads that can turn small fires into catastrophic events.

Biochar carbon removal reduces fire risk by collecting excess biomass—like dead trees, branches, and vegetation—from forest floors. This material is then heated in a low-oxygen environment, converting it into biochar: a stable, charcoal-like substance that can store carbon for centuries. The resulting biochar is primarily applied to nearby agricultural land, improving crop yields, water conservation, and fertilizer efficiency.

For example, the ongoing Oasis Vineyard Field Trial used our partner’s biochar made from high fire hazard forest residue. Over the past six harvests, biochar-treated plots had significant yield increases while using the same water and fertilizer as control plots. The benefits were most pronounced during challenging growing seasons, suggesting biochar helps vineyards become more resilient. The treatments proved profitable by the second harvest and showed dramatic returns by the sixth harvest, with potential benefits lasting throughout the vineyard's lifetime.

Josiah Hunt, CEO and founder of Pacific Biochar, will host a webinar on how vineyards can use biochar to improve soil health and resilience. Join the session on July 15th.

Reducing fire risk while enhancing agricultural productivity is a key opportunity for the state’s forest management. If scaled, our partner's modeling exercise found that using excess biomass in California for biochar production and applying it wisely could achieve a carbon drawdown of 9,165,021 tonnes annually, while improving crop yields, water conservation, and fertilizer efficiency.

Exploring how biochar works with clean energy

Earlier this year, the Wren team visited Shasta Sustainable Resource Management (SRM), a key facility in northern California for safely managing forest residue and reducing forest fire risk. Our partner, Pacific Biochar, offers consulting services for Shasta SRM, helping them optimize biomass production methods and develop quality control protocols.

The Shasta SRM facility processes around 1,250 tonnes of forest waste daily. We learned that 80% of biomass comes from high hazard forest zones, which are areas identified as having an elevated risk of wildfire, particularly dead or dying trees. This helps with fuel reduction and post-wildfire restoration. They process what would otherwise be hazardous fuel into clean energy capable of powering thousands of local homes and businesses, including their own.

During our visit, we observed their innovative processing systems and learned how they carefully monitor temperature and moisture levels to generate clean energy, with biochar as a climate-friendly byproduct. Looking ahead to 2032, Shasta SRM plans to expand their biochar production capabilities, working closely with Pacific Biochar along the way.

Biomass energy generation integrated with biochar production can provide renewable energy and carbon sequestration. During pyrolysis, plant biomass is thermally decomposed in limited oxygen, producing both energy and biochar. The integration of biochar with biomass energy aligns with Bioenergy with Carbon Capture and Storage, a climate solution recognized by the IPCC.

Facilities like Shasta SRM demonstrate how integrated biomass and biochar operations can address multiple environmental challenges. As more facilities adopt similar models, the potential for scaling biochar production while maintaining rigorous quality standards becomes increasingly achievable across California and beyond.

We’d like to thank Bryan and Mike from Shasta SRM for showing us around, as well as Josiah from Pacific Biochar for joining us and offering a partner perspective!

Issuing trusted, high-quality biochar credits

When you support projects through Wren, you can be confident that they meet rigorous standards for climate impact. One of the ways we ensure quality is through third-party oversight for carbon removal claims. This chain of custody helps scale solutions responsibly and efficiently.

Our partner, Pacific Biochar, is now working with Isometric under their Biochar Production and Storage protocol. The Isometric Science Team is larger than that of any other carbon registry and offers a public registry that makes the data behind every credit traceable from issuance to retirement—supported with documentation at every step.

This ensures verifiable proof that real climate benefit is carefully calculated, not just estimated or assumed. For example, the protocol determines how emissions are measured, what gets counted, and how long the biochar will remain stable in soil.

Biochar is one of the most promising carbon removal methods because it locks up carbon for centuries to millennia using existing biomass waste. It must be measured and verified properly in order to scale responsibly. By using the Isometric Standard, Biochar carbon removal commits to meeting one of the most rigorous, transparent, and science-backed frameworks for carbon removal.

Looking forward

Pacific Biochar is making steady progress behind the scenes. There are a few exciting developments on the horizon, including two new facilities coming online in California. These facilities will significantly increase biochar production capacity and help meet growing demand. We'll keep you updated as they develop and begin operations.

"Mitigating climate change has a collective action dilemma. Only when a critical mass of humanity is resolved to solve the problem will we be able to truly solve it, and it’s not clear if we’re there yet. We have most of the technical solutions we need to solve it, but on the whole we have not yet decisively chosen to use those solutions at the scale needed. Money likes certainty, and this sort of uncertainty in future demand of the core product we’re providing, a climate mitigation service, tends to be a point of tension with traditional financing options. That’s where solidarity comes in to save the day. Wren’s investment in Pacific Biochar helped fill the gap left by traditional financing options, and came at a critical time to help us continue scaling our mission to sequester carbon and leave a legacy of fertile soil." — Josiah Hunt, CEO and founder of Pacific Biochar

Beyond expansion and carbon credits, our partner is also developing an eco-friendly alternative to perlite, a common gardening material whose production typically relies on fossil fuels. This new product will offer commercial suppliers a more sustainable option for their horticultural products.

That's all for this update! As always, thank you for your support.

— the Wren team 🧡