Leaf shape is the most common tool used to identify trees
Dendrology (Ancient Greek: δένδρον, dendron, "tree"; and Ancient Greek: -λογία, -logia, science of or study of) or xylology (Ancient Greek: ξύλον, ksulon, "wood") is the science and study of wooded plants (trees, shrubs, and lianas). There is no sharp boundary between plant taxonomy and dendrology. However, woody plants not only belong to many different plant families, but these families may be made up of both woody and non-woody members. Some families include only a few woody species. This severely limits the usefulness of a strictly dendrological approach. Dendrology tends to focus on economically useful woody plants, their identification and horticultural or silvicultural properties.
Dendrology is often confused with botany. However, botany is the study of all types of general plants, while dendrology studies only wooded plants. Dendrology may be considered a subcategory of botany that specializes in wooded plants.