US solicits help as it defines old growth and mature forests

Assistant Fire Manager Leif Mathiesen, of the Sequoia & Kings Canyon Nation Park Fire Service, looks for an opening in the burned-out sequoias from the Redwood Mountain Grove which was devastated by the KNP Complex fires earlier in the year in the Kings Canyon National Park, Calif., on Nov. 19, 2021. Thousands of sequoias have been killed by wildfires in recent years. (AP Photo/Gary Kazanjian, File)