and the gains in participati that we've seen in the last couple of years are really hard won.esult of good work being done on the state and local level to keep more families engaged with the program. and we don't want to see folks turn away from the program because we know that once they fall off, it's really hard to get them back. congress needs to sustain these investments so that wic is reaching all of the families who would benefit from its vital nutrition services. >> nell menefee libbey with the national wicker association, thank you so much for your time. >> thanks for having me, ali. john: next saturday is the autumnal equinox, the beginning of astronomical fall in the northern hemisphere. for some, though, fall doesn't really begin until leaves change color. but scientists say climate change is affecting both the timing and intensity of fall foliage. earlier i spoke with bill keeton, a professor of forest ecology and forestry at the university of vermont. i asked him to explain why leaves change color in the fall. >> it's really a delicate dance between many factors t