What is a dichotomous key?
“Dichotomous” means “two-way”, or a fork-in-road. A dichotomous key is a tool designed to distinguish the differences among a set of objects, in this case, a group of trees. The key separates trees into various categories, based on physical characteristics, until there are only two species remaining. It’s sort of like a process of elimination. The use of keys requires careful observation and usually involves the learning of some basic terminology. Patience is often needed, especially the first few times working through the key. These are excellent decision-support opportunities. During the process, students learn quite a bit about trees, or whatever taxonomic group a key is designed for. It is the beginning of a better understanding of trees, forests, and natural resources.
