Fall 2023 pine beetle and drought mortality in Mississippi and Louisiana
Fall is an especially challenging time of year to map forest disturbances in the east due to the senescence of deciduous forests. While pines lack this foliage decline, when they are killed it is difficult to isolate their death from the senescence of the surrounding deciduous trees, particularly outside pine plantations. In the fall of 2023, a severe drought triggered a pine beetle outbreak (largely thought to be from Ips beetles) in Mississippi and Louisiana. This caused large numbers of pine to suddenly die during November and December. This provided an opportunity to refine HiForm's mapping capabilities for scattered small outbreaks that extend over a vast area in near-real-time.
The HiForm workflow includes a combination of HiForm's standard change-over-time process and a novel masking routine that first isolates the pine using a winter/evergreen mask, then a recency mask that ensures that the pine had not been logged or otherwise lost in the months prior to the start of the Ips outbreak (i.e., just since mid September). This landscape has considerable disturbance activity from clearcut logging that was non-targeted change.