Fungal Inoculation Transforms Southern US Pine Forestry
At a commercial tree nursery near Evans, western Louisiana, millions of pine seedlings are densely packed onto vast irrigation tables, each spanning the width of a football field. In September, many of these young trees received a spray resembling muddy water, but this substance was a liquid extract teeming with hundreds of species of wild soil fungi. Brad Ouseman, the nursery manager, anticipates visible results from this fungal inoculation, which is designed to improve yields and decrease dependence on artificial fertilizers.
"By the time January arrives, you'll notice a clear difference between the sprayed and non-sprayed seedlings," Ouseman explains, pointing to distinct rows of treated and untreated pines. Colin Averill, founder of the startup Funga, compares this treatment to a fecal microbiome transplant for young pine trees. Similar to medical procedures that transfer gut microbes from healthy donors to patients, Funga administers wild microbes from thriving pine forest soils to young trees.
Harnessing Soil Complexity for Enhanced Growth
"We're not isolating individual components of the soil community; we're utilizing the entire ecosystem," Averill emphasizes. "This approach captures all the complexity and interactions inherent in natural systems." The primary goal is to cultivate trees that grow rapidly, sequester more carbon dioxide, and rely less on artificial fertilizers. The Evans nursery supplies an extensive network of intensively managed pine plantations, covering over 12 million hectares across 13 southern US states, known as "the woodbasket of the world."
Loblolly pines, native to the southeastern US, depend entirely on underground fungal partners. Ectomycorrhizal (ECM) fungi integrate into pine roots, forming what Kabir Peay, a Stanford fungal ecologist, describes as a "hybrid organ"—part plant, part fungus—that functions as a trading platform for essential nutrients. These fungal networks extend into the soil, scavenging nitrogen, phosphorus, and other nutrients, which they exchange for energy-rich sugars from the tree. Peay notes that pines and ECM fungi are interdependent: "We rarely find one without the other."
Addressing Fungal Depletion in Timber Harvests
Peay's research indicates that soil fungal biodiversity is crucial for healthy trees and forests. Individual trees may associate with hundreds of fungal species, each accessing different nutrients under varying conditions. A 2018 study demonstrated that even a two-month delay in seedlings acquiring appropriate fungi can significantly hinder their growth. Across the southern pine belt, clearcut timber harvests severely deplete the fungal communities essential for young trees, leading to suboptimal growth and increased reliance on artificial fertilizers.
Funga's genomic surveys suggest that approximately 75% of ECM fungal diversity vanishes after felling, a figure consistent with studies from Scandinavian and Canadian pine forests. The company estimates recovery takes about 30 years, but trees are harvested on 15- to 25-year cycles, implying some pines may never experience fully mature ECM networks. Rachel Cook, a forestry professor at North Carolina State University, cautions that the recovery timescale for ECM fungi remains an unresolved scientific question. She acknowledges major disruption but suspects warmer southern soils may facilitate faster recovery than Funga's estimate.
Scaling Up with Promising Early Results
Funga argues that trees benefit from early exposure to productive ECM fungi. The team surveys forest soils across the southeast, identifying thriving fungal communities for use as inoculants in small trials. Promising communities are cultured using natural organic matter as substrate, essentially creating in-forest compost heaps, before extracts are applied at scale in industrial nurseries. Founded in 2022, the company inoculated about 500 acres in its first year, scaling to approximately 25,000 acres by 2025. Averill estimates that Funga treated one in 40 of all loblolly pines planted in the southeastern pine belt last year.
Early results are encouraging. "We've observed growth responses exceeding 100% in some locations," Averill reports. "Overall, we target a 30% average growth boost and believe we're close to achieving that." Cook, who co-directs the Forest Productivity Cooperative, notes that a 30% increase from fertilization is typical, suggesting Funga's biological treatment may rival gains from expensive chemical inputs. "I think this could be a significant advancement in managing southeastern forests," Cook says. "I'm cautiously optimistic, but more data is needed."
Overcoming Soil Deficiencies and Market Challenges
Soils beneath southern pine plantations often lack key nutrients, a legacy of intensive tobacco and cotton agriculture before commercial forestry began in the 1930s. Under nearly a century of continuous forest cover, these soils are slowly recovering, but nutrient shortfalls persist. Cook clarifies that pine stands, fertilized at most three times in 25 years with minimal soil disturbance, are far less intensive than agriculture. Averill hopes fungal inoculation could eventually replace chemical fertilization entirely, offering a low-cost, sustainable alternative to fossil-fuel-dependent inputs.
Previously in academia, Averill's research showed that soil fungal community composition predicts forest growth and carbon sequestration as strongly as rainfall. He founded Funga in 2022, betting on environmental markets as a financial engine to translate research into climate and biodiversity solutions. In 2025, Funga signed an 11-year, multimillion-dollar carbon removal deal with Netflix. Carbon markets face scrutiny, with a 2025 review highlighting issues like non-additionality and impermanence. Averill acknowledges greenwashing risks but argues Funga's model addresses these by basing credits on additional growth relative to control plots and requiring timber use in durable products like lumber.
Expanding Beyond Southern Pine
Because Funga's treatments are funded by carbon revenue, landowners incur no costs to participate. However, fungal inoculation must eventually prove its economic value against fertilizers for budget-conscious land managers. Funga's ambitions extend beyond southern pine, with targets including Douglas fir in the Pacific Northwest and trials in Wales involving broadleaf trees and Sitka spruce. Peay believes the real breakthrough lies in deciphering the ecology of poorly cataloged organisms. If Funga can identify optimal fungal communities and transfer them efficiently to young trees, it could mark a major advancement in forestry science.
