Ash Trees (IMAGE) Penn State Caption Researchers began measuring the decline of ash trees in the Penn State plantation in 2012, shortly after emerald ash borers arrived there, and they measured it every year through 2017. The effect of the insect was devastating. Credit Kim Steiner, 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.