Dwayne Estes June 5, 2017 Check out Chris Helzer's great webinar on using fire and grazing to manage prairies. Dwayne Estes June 5, 2017 Chris Helzer (The Nature Conservancy). 1 June 2017. Using Fire and Grazing to Maintain Productive and Ecologically Resilient Grasslands. Webinar (original) available via USDA's Science & Technology Training Library Webinar Portal for Conservation of Natural Resources. 1 hr, 4 min.