Tree species worldwide (IMAGE) Purdue University Caption The number of tree species and individuals per continent in the GFBI database. Credit Purdue University image/courtesy of Jingjing Liang Usage Restrictions No restrictions. License Public Domain 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.