Layers of ice and tree rings are similar in that they can both record or store data from past environmental conditions. The study of tree rings is known as dendrochronology and it involves counting and studying individual rings in the tree. Each ring represents a year or specific growing period. If the ring is smaller it means there might have been a drought or nutrients were low. A larger than average ring would represent an unusually favourable growing season. Layers of ice in an ice sheet trap information that can tell about past conditions such as climate. Just like the tree rings specific sections represent a specific period of time. Air bubbles trapped in ice provides information on past climates.