California statewide wildfire burn regime projections (2020-2100)

At the intersection of climate change and rural development, wildfire has
emerged as a threat to agriculture in the western United States. This
nexus is particularly problematic for the rapidly developing cannabis
industry in California, which includes farms located outside of
traditional agricultural zones and within landscapes potentially more
prone to wildfire. With the goal of determining whether cannabis is
uniquely vulnerable to direct wildfire impacts (in terms of crop loss to
burning), we integrated fire hazard severity zone data, wildfire
perimeters, and future burn regime projections in relation to the location
and cultivated area of cannabis farming. We then applied descriptive
statistics and generalized additive models (GAM) to compare the location
of licensed cannabis farms to other agricultural types in California,
including grapes, pasture, and all other general crops combined. We found
cannabis farming was located more often in high and very high fire hazard
severity zones and closer to wildfire perimeters than any other
agricultural type. GAM estimates of likelihood of occurrence in high and
very high severity zones were highest for cannabis, even after accounting
for spatial clustering of farm types, although there was no reliable
difference in predicted distances to wildfire. Cannabis more often
occurred in projected (from 2020-2100) wildfire hotspots than all other
agricultural types, with GAM estimates affirming a reliably higher
likelihood of cannabis in future hotspots than pasture or general crops.
Our findings highlight cannabis’ particular vulnerability to wildfire in
California, and may in fact underestimate wildfire risks given the
potential indirect impacts of smoke to crops and farmworkers, which were
not evaluated in this study. In light of the sector’s growing economic
importance in the state, these vulnerabilities should be considered in
future cannabis and rural development policies.