By Mina Kim and Lisa Pickoff-White

California's awe-inspiring, ancient redwood trees are increasingly the target of timber thieves. The practice of burl poaching has increased so significantly that, on March 1, Redwood National and State Parks began closing the scenic road through the park every night. The park is also increasing patrols.

A burl is the knobby growth often at the base of trees, which is filled with unsprouted bud tissue. If the redwood falls, the burl can sprout another redwood tree. So, although one redwood tree can live up to 2,000 years, one burl can hold the DNA of trees that have been growing for 20,000 years, according to Jeff Bomke, sector manager for California State Parks of the Redwood Coast. Cutting burls essentially ends the genetic life of a line of trees.

Burls are often used to make souvenirs or ornamental furniture that can command a high price. Bomke said there has been a dramatic increase in the number of trees poached during the last two to three years. About 15 trees were cut in February.

"What's most concerning now is that the thieves have resorted to felling standing old-growth trees to reach burls that are on the stem above the ground," Bomke said.