Expanding Our Understanding of Forest Structural Restoration Needs in the Pacific Northwest

Ecological departure, or how much landscapes have changed from a natural range of variation (NRV), has become a key metric in forest planning and restoration efforts. In this study we define forest restoration need as the specific change in structural stage abundance necessary to move landscapes into the NRV. While most restoration projects in the forested ecosystems of the Pacific Northwest, USA (Oregon and Washington) have embraced this paradigm, our understanding of what treatments to apply where, when, and at what magnitude is evolving and continues to be refined. We build on a body of existing LANDFIRE/Fire Regime Condition Class (FRCC) work on ecological departure to assess the ecological departure of all forested landscapes in the region. Moreover, we assess departure in moister forests west of the Cascade crest, and compare them with fire-dependent forests east of the crest and in southwest Oregon. These “moister Westside” forests have received relatively less attention in a fire ecology context, and we hypothesize restoration needs there are quite different. We show a substantial need for disturbance-related treatments in the drier fire-dependent portion of this region (east of the Cascade crest plus southwest Oregon), with over half of this treatment type falling on Federally-administered land. On the Westside the need for succession is more pronounced. The lack of pronounced disturbance need west of the Cascade crest suggests restoration there may require strategies more nuanced than in the fire-dependent zone.