A scientist who studies trees is called a dendrologist. Dendrology is the branch of botany or forestry that focuses on the identification, classification, and study of trees and woody plants. Dendrologists often investigate various aspects of trees, including their taxonomy, physiology, ecology, distribution, growth patterns, and interactions with other organisms and the environment. They may work in various settings, including research institutions, universities, government agencies, and conservation organizations, contributing to our understanding of tree biology and the role of trees in ecosystems.