When the Los Angeles wildfires tore through Southern California in January 2025, they left behind 30 deaths, 150,000 evacuations, and economic losses estimated at $140 billion, the costliest wildfire disaster ever recorded. It was not an anomaly.
Between March 2024 and February 2025, wildfires scorched 3.7 million square kilometres worldwide, an area larger than India, while emitting over eight billion tonnes of CO₂. Climate change has made extreme fire weather 88 to 152% more likely across global forests compared to pre-industrial conditions. The traditional playbook, periodic tree trimming and reactive firefighting, is no longer enough.
Fiona Spruill, CEO of Overstory, is building something different.
Founded in 2018 in Amsterdam, Overstory began as a deforestation-tracking tool before pivoting to wildfire prevention after identifying a more urgent opportunity. The realisation, as Spruill described it: “We could have a huge impact from a climate standpoint, in that we could help prevent wildfires.”
Today, the company uses high-resolution satellite data and AI to assess vegetation risk tree by tree, identifying dying trees, encroaching brush, and fuel-heavy zones before they can spark a disaster. Overstory’s models are trained on ground-truth data from a team of arborists who provided on-the-ground measurements of diseased and dying trees, giving the platform an ecological depth that pure remote sensing cannot replicate. Because climate change is altering how and where trees die, Spruill notes that maintenance plans that “may have worked 10 years ago are not necessarily going to work anymore.”
For electric utilities, vegetation is the leading cause of outages and wildfires, and often their single largest operational expense. What Overstory offers is precision where there was previously guesswork: instead of blanket trimming schedules, utilities receive specific guidance on which tree to cut, which pole to clear, which asset to replace.
The platform’s latest evolution, a proprietary Fuel Detection Model launched in November 2025, goes further still, pinpointing locations across a utility’s network where fuels are highest and a spark is most likely to spread, then recommending prioritised actions.
Andy Abranches, VP of Wildfire Mitigation at PG&E, credited this kind of intelligence as the missing piece behind two devastating 2018–2019 fires, the Kincade blaze and the deadly Camp Fire, both ignited by dry brush beneath transmission towers. “Even if the equipment failed,” he said, “the sparks that it threw would have landed on bare earth. There would have been no fire.”
That precision has earned Overstory the trust of six of the ten largest utilities across the Americas and more than 50 utilities globally. In November 2025, the company closed a $43 million Series B round led by Blume Equity to accelerate its AI risk models and expand internationally. Its 80-person team spans 16 nationalities, blending machine learning engineers with arborists and wildfire specialists, a pairing that reflects the nature of the problem: part data science, part deep ecological knowledge. What Overstory represents is a broader imperative, using frontier technology not merely to respond to climate disasters, but to anticipate them.
Wildfires cost the U.S. Forest Service and Department of the Interior, an average of $2.9 billion per year in suppression costs alone over the last decade, a figure projected to rise 42% by 2050.
The intelligence to act before the spark, tree by tree across entire grids, may be one of the most consequential climate investments of this decade. As Spruill and her team scale that capability globally, the forests are no longer facing the future alone.
Sources:
- Earth System Science Data – State of Wildfires 2024–25
- Eurek Alert – ‘Climate change drove extreme wildfire seasons across the Americas, making burned areas around 30 times larger.
- Nature Communications – ‘Climate change has increased the odds of extreme regional forest fire years globally.’
- Bloomberg – ‘How AI Can Help Reduce Wildfire Risks’
- Insurance Journal – ‘Massive Wildfire Liabilities Push Utilities to Use AI to Stop Blazes’
- PRNewswire – ‘Overstory Closes $43m Series B To Scale AI-Driven Wildfire Prevention And Grid Resilience’
- ESG Today – Overstory Raises $43 Million to Help Utilities Avoid Wildfires with AI
- Center for Climate and Energy Solutions, 2026 – Wildfires and Climate Change
