Advanced Training – TSS Domain – Winter Tree Identification Module

Course Description

The Winter Tree Identification module will provide an in-depth study of several significant tree species found in Illinois. Identification based on bud, stem, bark and fruit/seed characteristics will be the primary focus for each tree species studied. We will also cover other features important for winter ID, such as tree branching patterns, overall form, even taste and smell. Keen observation skills are necessary for plant ID during the dormant period. Once accomplished attendees will realize that the dormant period provides a more accurate and reliable season to identify tree species. Classes will consist of an indoor study session and an outdoor observation period where specific examples of trees studied in the classroom will be examined. Over 75 different tree species (deciduous and evergreen) will be studied during the course. A 20-question multiple choice quiz will be given at the end of class.

Recommended Reading

Fruit Key and Twig Key to Trees and Shrubs, William M. Harlow, 1946
Woody Plants in Winter, Earl L. Core & Nelle P. Ammons, West Virginia University, 1958

Provided Equipment

Pocket knife, 10-15X hand lens, hand pruners, pruning saws and pole pruners.

Day One

During the morning session, we will review plant taxonomy, nomenclature and morphology. We will also discuss approximately 35 tree species via a PowerPoint presentation. Matching live samples will also be available to help ID the different species. The afternoon session will consist of “hands-on” field trip to put your ID skills into practice.

Day Two

The morning classroom session will review an additional 40 tree species via PowerPoint presentation, along with live samples. The afternoon session will consist of another “hands-on” field trip to ID the remaining species.


The arborist will become proficient in recognizing various plant features that will greatly improve their ID skills, especially during the dormant period.