Local News Controlled Burn At DBG March 7, 2013 / 12:26 PM MST / CBS News (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: Denver Botanic Gardens) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: Denver Botanic Gardens) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: Denver Botanic Gardens) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: Denver Botanic Gardens) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: CBS) A controlled burn took place at Denver Botanic Gardens on March 7 to "replicate the natural processes that help to maintain grassland ecosystems." (credit: Denver Botanic Gardens)