White Oak Foliage

Arnold Arboretum Tree Spotters

Arnold Arboretum of Harvard University

  • March 1–November 30

This is an ongoing Citizen Science Experience. Contact the sponsoring organization to join in.



High Adventure





Arnold Arboretum Tree Spotters Logo

With nearly 4,000 different kinds of plants represented in the Arnold Arboretum’s living collections, every day presents rich opportunities to see something new. If you enjoy learning about plants and their unique characteristics, you can contribute to science as a participant in our Tree Spotters program, based at the Arnold Arboretum of Harvard University in Boston, MA. This citizen science project opens a window into the Arboretum’s phenology: the timing of natural events, such as the leafing out and flowering of trees in the spring and changing foliage colors in the fall. Your observations will assist Arboretum scientists in their studies of the effects of a changing climate on plants. All levels of experience are welcome.

Program Information and Training Sessions

Free training for all participants. All levels of experience are welcome.

Once trained, Tree Spotters participate in the program by visiting the Arboretum two or more times a month from March through November for a 1- to 2-hour tree-spotting session. You can go Tree Spotting on your own, with friends or family, or with other volunteers. Tree Spotters offers a selection of 57 trees and 15 shrubs that you can follow. You get to decide which ones you will observe. You will enter your observations into your Nature’s Notebook Observation Deck (an online database created and supported by the USA National Phenology Network) that allows you to see patterns across the seasons and across the years.

Tree Spotters Website

Youth Instructions

Youth are welcome to participate.