Infra Red Forest Fire (IMAGE) Penn State Caption This infrared image shows that long-duration heating was most prominent where accumulated forest floor duff was deepest, particularly at the base of mature pines in long-unburned sites. Temperatures potentially lethal to plant tissues were sustained for several hours as deep as 4 inches near pines, and sustained temperatures high enough to impact soil nutrients were observed for up to 35 minutes at soil surfaces. Credit Jesse Kreye, Penn State Usage Restrictions non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.