The Forest and Rangelands Renewable Resources Planning Act (RPA) of 1974 requires the Forest Service to prepare an assessment of renewable natural resources on all the nation’s forests and rangelands. The RPA Assessment, updated every five years, provides a snapshot of current U.S. forest and rangeland conditions and trends on all ownerships; identifies economic, social, and biophysical drivers of change; and projects conditions 50 years into the future. Resources covered include forests, rangelands, urban forests, forest products, carbon, wildlife and fish, biodiversity, outdoor recreation, wilderness, water, and the effects of socioeconomic and climate change on these resources.  

A chapter focused on disturbances to forests and rangelands is being included for the first time in the 2020 RPA Assessment (anticipated publication early 2022). The chapter will focus on fire, drought, invasive species, and outbreaks of insects and diseases. Air quality as an ecological stressor will be included in the chapter as a sidebar with the goal of creating a platform from which future RPA work can explore current and projected impacts of air quality under different future scenarios.

Within the sidebar, EPA’s Critical Loads Mapper is used to provide an illustrative example of how to understand air quality issues such as deposition and their impacts through critical loads. The advances in deposition and mapping critical loads allow us to demonstrate one way to make projections of future impacts and analyze future trends, demonstrating the relevance of addressing air quality in future RPA Assessments. The work of NADP and in particular CLAD is foundational to allowing us to make this demonstration and incorporate deposition and critical loads into the 2020 RPA Assessment.