Flammability thresholds of Eastern redcedar as a potential indicator for heightened wildfire danger

Flammability thresholds for Eastern redcedar (J. virginiana), an invasive native tree commonly planted throughout the Great Plains, were determined for an August 2016 study conducted in the Twin Lakes Wildlife Management Area (WMA) in Seward, County, Nebraska. This data publication includes flammability measurements for 100 Eastern redcedar twigs across a foliar moisture content gradient ranging from 0% to 180%. To limit the amount of variation in foliar fuel moisture content (FMC) among foliage samples, all samples (6 centimeters in length) were harvested from the lower third of the crown of a single adult female tree and from the tips of branches only. Using a MC320LHT thermal imaging camera, three common characteristics of flammability were measured: ignitability (time until ignition), sustainability (time-spent combusting), and combustibility (intensity of combustion). Data indicate that flammability thresholds exist for Eastern redcedar and are expressed primarily through measurements of ignitability (time until ignition). At fuel moisture content’s of approximately 80%, time to ignition rapidly decreases. Based on these findings, the flammability of Eastern redcedar and its associated wildfire risk is much higher during periods of drought and should be considered as part of wildfire danger monitoring protocols in the Great Plains region.
Data were collected to identify the tipping point at which rapid changes in flammability of Eastern redcedar occur during drought. Identifying a tipping point in flammability provides new information to wildland firefighters on the level of foliar moisture content representing when Eastern redcedar will abruptly increase in flammability - and thus represents a proxy for a rapid change in wildfire risk.