Brian first became interested in big-tree hunting through American Forests, a nonprofit that had catalogued significant specimens across the United States through the national Register of Champion Trees. The register started as a short list of 77 big trees featured in the April 1941 edition of American Forests magazine. By 2021, it had grown to 562 Champion Trees across the country. Since 2023, the program has been adopted by the University of Tennessee School of Natural Resources, but the full list of Champions is accessible through the National Champion Tree Program website, which features trees by state, the year nominated, and their accessibility to the public.