INVASIVE EUCALYPTUS AND WILDFIRE RISK
Understory + Eucortex
THE IMBALANCE
Eucalyptus was brought to California in the 1850s and took hold too well, now feeding wildfires that put the Bay Area at growing risk. Removing it costs municipalities millions each year, and most of what comes down gets chipped and sent to the dump, releasing all the carbon it sequestered. What a waste of untapped potential.
THE PROBLEM IN CONTEXT
During my research, I came across another species whose range is expanding under climate change: the Western black-legged tick, a carrier of Lyme disease. Ticks favor dense undergrowth and heavy leaf litter, precisely the conditions found in a eucalyptus grove, which puts forestry workers and land stewards at elevated risk of exposure. But eucalyptus oil is also known to repel and kill ticks. The relationship struck me as worth pursuing: removing eucalyptus to prevent wildfire creates a secondary exposure to ticks, yet the eucalyptus itself carries the means to address that exposure. I began to wonder whether the protective gear worn during eucalyptus remediation could be made from the very material that brought workers into the grove in the first place.
THE INTERVENTION
Eucalyptus-based bioleather gaiters that protect the wearer from ticks carrying Lyme disease.
Eucortex is a non-woven textile made from eucalyptus bark fiber, transforming biomass that would otherwise be treated as waste. It became the foundation for Understory, functional workwear built for those who move through the hazardous, overgrown terrain where eucalyptus is being removed: ecologists, restoration crews, land stewards, the people doing the work of wildfire prevention and native ecosystem recovery.
For Understory's first garment, and to test Eucortex's suitability as workwear, I designed a pair of gaiters, since the lower leg is where ticks most often make contact. Cotton thread and minimal fasteners keep the garment easy to take apart at the end of its life, so it can be returned to the same forest it came from. Gaiters serve as the proof of concept for what could become a much larger line.
PROTOTYPING AND ITERATION
Eucortex starts as a thick, viscous liquid; the bark fiber is mixed into a solution of carboxymethyl cellulose, microcrystalline cellulose, water, and glycerin. The water is evaporated out in an oven, leaving the film behind. The only real limit on the material's size is how large an oven is available. I went through many, many prototypes trying to get the balance right: dry, but not dried out; flexible, but not falling apart; thin enough for apparel, but thick enough for workwear.
I gathered bark, leaves, and seed pods from the hills and examined each component's properties: the leaves resiny and plasticky, the bark fibrous, the pods full of oil. A weak solution of sodium hydroxide broke down the lignin between bark fibers, which could then be mechanically separated into fluffy strands with a rich rust hue. Harvesting the fibers efficiently, without machinery or complex tools, was its own challenge; carding, working the material against a barbed board with a hooked paddle, turned out to be the low-tech solution that worked.
HOW IT WORKS
The result is a bio-leather that's flexible and durable, though as a non-woven textile it's vulnerable to shearing. I solved that by reinforcing the sheets with a layer of lightweight muslin, fused in during the baking process. Eucortex resists mold and shows no sign of breaking down under normal wear. As a leather-like textile it keeps carbon sequestered for longer, and at the end of its life it can be buried, extending that storage before it eventually decomposes and returns nutrients to the soil. It's flexible enough to withstand regular use as well as more demanding handling, and it can be cut and sewn much like traditional leather. Its porosity completes the tick-protection loop: the material absorbs and holds eucalyptus oil, giving the finished garment the same repellent property as the tree of origin.
CURRENT STATUS AND REFLECTIONS