Here is the link to a long-awaited publication! Read it now so you will be prepared to use the immense amount of data from more than 8,300 lichen plots. These data have already been used as a baseline for tracking air quality, climate in 90 different studies.
https://www.fs.usda.gov/treesearch/pubs/61432
Unfortunately, if you want to use these data, you will need to get in touch with Sarah Jovan until the FIA webpage is up and running.