Lost and found: how police search and rescue tactics helped track down a rare oak

The last Quercus tardifolia was thought to have died in 2011 - until a team of researchers fanned out and combed through Big Bend national park in Texas

It was like when folks go searching for a lost child in the woods," says Michael Eason, associate director of conservation and collections at San Antonio Botanical Garden. Our team would spread out in a line, spaced about 30 metres apart, and comb through an area."

Rather than a scene from a TV crime series, this search and rescue team of nine botanical researchers was scouring Big Bend national park in Texas this May looking for Quercus tardifolia, also known as the Chisos Mountains oak or lateleaf oak. The tree was first described in the 1930s, but the last living specimen was believed to have perished in 2011.