Sampling a Tree (image) University of Arizona Share Print E-Mail Caption Dendrochronologists extract a small, pencil-shaped sample of wood from a tree with a tool called an increment borer. The tiny hole left in the tree's trunk quickly heals as the tree continues to grow. Credit Daniel Griffin/Laboratory of Tree-Ring Research Usage Restrictions This visual may only be used in conjunction with reporting/posting of this news release. Image/video credit must be included. Share Print E-Mail 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.