To cite package ‘FIAstemmap’ in publications use:

  Toney C, Shaw JD, Nelson MD (2009). “A stem-map model for predicting
  tree canopy cover of Forest Inventory and Analysis (FIA) plots.” In
  McWilliams W, Moisen G, Czaplewski R (eds.), _Forest Inventory and
  Analysis (FIA) Symposium 2008_, number RMRS-P-56CD. USDA Forest
  Service, Rocky Mountain Research Station, Park City, UT.
  <https://research.fs.usda.gov/treesearch/33381>.

A BibTeX entry for LaTeX users is

  @InProceedings{,
    title = {A stem-map model for predicting tree canopy cover of Forest Inventory and Analysis (FIA) plots},
    author = {Chris Toney and John D. Shaw and Mark D. Nelson},
    year = {2009},
    booktitle = {Forest Inventory and Analysis (FIA) Symposium 2008},
    editor = {Will McWilliams and Gretchen Moisen and Ray Czaplewski},
    month = {October 21-23, 2008},
    address = {Park City, UT},
    number = {RMRS-P-56CD},
    organization = {USDA Forest Service, Rocky Mountain Research Station},
    publisher = {USDA Forest Service, Rocky Mountain Research Station},
    url = {https://research.fs.usda.gov/treesearch/33381},
  }