KVI's Kirby Wilbur, substituting for John Carlson, interviews UW Atmospheric Sciences professor, Cliff Mass, about the recent health concerns in New York City and the Northeastern seaboard over Canadian wildfire smoke. Mass just wrote an explanation about the Canadian wildfire smoke problems for the Wall Street Journal. He says some tree species can't reproduce without fire, how forests grew dense over the last 100 years leading to pronounced forest fire problems, a brief history on forest management dating back to indigenous tribes, how logging and timber harvesting reduced forest fires.