You will find a viewer-friendly PowerPoint on the growth rings and other features found in a cross-section of a tree trunk, affectionately known as a "tree cookie." A few worksheets are provided for practice counting tree rings and a short video introduces your class to the oldest living trees, the Bristlecone Pines. This is not a formal lesson write-up, but rather a collection of resources to use with your upper elementary or middle school life science curriculum.