Hemlock woolly adelgid-induced losses in riparian corridors in New York State

The loss of eastern hemlock (Tusga canadensis) due to the invasive pest hemlock woolly adelgid (Adelges tsugae; HWA) could have profound impacts to riparian forest function and provisional services. Following a request by collaborators in New York State (NYS) to identify and prioritize riparian corridors at potential risk of future hemlock losses due to HWA, we created risk maps using three riparian buffer widths (50-, 100-, and 200-ft) for NYS. We expressed projected basal area (BA) losses two ways: in ft/ac and as a percentage of total stand BA. We found that the central and southern portions of the state are at risk of greater losses of hemlock in the riparian corridor, which could influence water quantity and quality adjacent to large population centers (e.g., New York City). Because of the large size of the pixels used to represent loss (240m x 240m, 14.23 ac), we found that the width of the riparian buffer (i.e., 50-, 100-, 200-ft) did not drastically influence the projected losses. As the density of streams in NYS is high, we recommend using our sub-catchment level maps for identifying watersheds with elevated potential BA losses, and then pinpointing stream corridors within the sub-catchment for research, monitoring, or future management and restoration efforts.