POLK COUNTY, Fla. – On a warm morning in Polk County, heavy equipment hummed through rows of citrus as a mobile carbonizer known as a “Tigercat” converted trees and grove debris into biochar — a porous, charcoal-like material that project leaders say could help hold water and nutrients in sandy Florida soils, reduce greenhouse emissions from burning, and even filter polluted water.
The project, operated on a 35-acre pilot site donated by a local grower, is testing whether woody waste from dying citrus groves can be turned in place into a stable carbon product and then used to improve soil and storm water runoff.
“We cleared the whole thing in three days,” said Zach Farr, CEO of Biotech Applied Research, describing the first phase of work on the decommissioned Valencia orange grove.
The Tigercat, which resembles a large garbage dumpster, runs hot — operators say it reaches about 2,000 degrees and can char a tree in roughly 30 seconds — and because it is portable, crews can process debris where it stands rather than hauling it long distances.
Fans create a “curtain of air” over the top, keeping most of the emissions inside.
The burnt wood is mixed with water and comes out on a conveyor. Operators can adjust the density or size of the chips depending on their application.
Farr described biochar as a sponge and a microbial “condominium” for soil life. “One gram … has the same amount of surface area as a tennis court,” Farr said, adding that biochar holds multiple times its weight in water and creates safe habitat for microbes that help retain nutrients rather than letting them leach into aquifers.
Jason Vogel, an associate professor in the School of Forest, Fisheries and Geomatics Sciences at the University of Florida was there to see the demonstration.
Vogel said adding biochar to Florida’s sandy soils can slow nutrient loss and increase water and nutrient retention for tree roots — a potentially important benefit in regions that struggle with low-organic soils.
“The value of these systems is that you can move them to the location of your debris,” Vogel said, adding that most debris has to be brought to large incinerators miles away. “All of that costs a lot of money. It puts a lot of wear and tear on the roads and it takes a certain amount of expertise.”
Another benefit is the biochar can be used on site to enrich the soil.
“The soils in our area, once they’re put into agricultural production they lose that organic material,” Vogel said. “So this is a quick way of getting that reinjected into the system. So that’s exciting.”
Florida’s citrus industry has declined sharply over the past two decades because of hurricanes, disease and pests. Central Florida once supported hundreds of thousands of acres of citrus; today far less productive land remains.
That changed landscape has left growers with large volumes of dead or dying trees — material that is often burned or left to decompose.
Farr hopes that turning that biomass into biochar is a more sustainable alternative that can create a marketable product and reduce smoke and carbon emissions.
“If you just set this stuff on fire, it goes up into the atmosphere,” Farr said, noting a prior EPA grant submission that estimated roughly 10 tons of carbon dioxide could be released per acre when groves are burned.
The pilot is working with University of Florida researchers and local partners to test how much biochar per tree and per acre is needed, and how the product performs in real soils.
Jeff Williams, an investor and board member with Biotech Applied Research, said UF is running a study on a 20-acre block in Avon Park to measure water retention and nutritional benefits on treated trees.
The team is also testing “stormwater biochar socks” — mesh-filled cartridges that can be placed in drains, canals or flow paths to capture pollutants before they flow into lakes and streams.
Beyond environmental gains, Farr hopes to create local jobs and reduce disposal costs for growers.
“Farmers are paying to clear their groves,” Farr said.
The pilot hopes to offer a lower-cost alternative that lets farmers keep some revenue, produce a useful product, and return carbon to the soil — a circular bioeconomic approach that could add value while helping restore soil function.
The team is exploring scale-up options, including additional machines and feedstock beyond citrus such as invasive species or yard debris.
Biotech Applied Research is hoping for further grant support and additional partners to expand testing and deployment. Meanwhile, they continue to collect field data with University of Florida collaborators and to deploy small storm water filtration systems to test water-quality benefits.