Poplar Movie (video) Penn State Loading video... Caption This is a video of researchers describing their work on transgenic poplar trees to reduce lignin problems. Credit Amitabh Avasthi, Penn State Usage Restrictions Not for advertising use. 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.