There are an estimated 6.3 billion dead trees currently across western U.S. forests, a legacy from increasing frequency or severity of beetle infestations, wildfires, and droughts against a backdrop of regional warming. A critical question remains: have forests recovered from these disturbances over the last 36 years? Leveraging three core forest sites in the Southern Rockies, Northern Rockies, and Pacific Northwest that are part of the National Ecological Observatory Network (NEON), this work will explore:

1. What combinations and sizes of disturbances create abrupt and persistent forest changes?
2. How does forest resilience vary as a function of forest type, drought, and regional warming?

This effort will explore these questions by integrating data from individual trees to entire ecoregions to advance understanding of western forest recovery. A novel, core scientific community, the NEON Resilience Network, will be enabled for data-intensive exploration of resilience using an open-source NEON toolkit that contains data, code, methods, and three software packages. In addition, sustained touchpoints will be made with regional and federal land managers developing best-practices for how to resist, adapt, or facilitate ecological transformation. This connection offers a critical co-production pathway, directly connecting NEON-enabled scientific discovery and public lands management decisions.

This project will advance theoretical understanding of how resilience varies as a function of compound, large disturbances, within and among ecoregions, and with decadal-scale regional warming. These are essential macrosystems ecological questions to address for western U.S. forests. This research will apply deep-learning techniques to identify individual plant species from NEON’s airborne data collections of hyperspectral, LiDAR (light detection and ranging), and red-green-blue imagery, helping to advance a research frontier. Coupled with extended sampling via unmanned aerial systems (UAS), the research will develop vegetation class spectral signatures to derive annually-resolved plant functional type maps (coniferous forest, deciduous forest, woody shrub, grass/herb, and bare ground) from the Landsat satellite record (1984-present), providing an unprecedented temporal reconstruction of western U.S. forest dynamics. The NEON Resilience Network will also scale core resilience questions across the continental U.S., asking: are there predictable combinations, sequences, or sizes of disturbances that lead to more persistent state changes across vegetation types? This research will help unlock the power of the Landsat record to explore forest resilience in the western U.S., setting an important historical baseline as NEON embarks on monitoring continental-scale forest ecology over the next 30 years.

Funding for this project was provided by NSF Award #DEB 2017889.