This event, as you can probably guess by the name, is all about trees. For this event, Wikipedia is highly recommended as it contains the most information, but it is also important to use other sources to gain a variety of information. It is important to know how to navigate your binder, and also to practice identification for this event because even though it is a binder event, you are limited on time and you will not get through the event without studying. Things to include in your binder are unique facts, identification photos, tree anatomy, tree-related world records, tree diseases, uses for specific trees, lifespan, etcetera. Helpful resources (besides wikipedia, as that is on the home page/easy to find) are linked below.
For this event you are allowed to bring a writing utensil, an unedited copy of the national tree list (or the state tree list if they provide a separate one), a commercially produced field guide which may be annotated and tabbed, and a 2" or smaller 3 ring binder, as measured by the diameter of the rings. The binder may have laminated sheets, sheet protectors, tabs, annotations, and material from any source, but everything must fit within the rings of the binder (no pockets unless it's the tree list!). Links for purchasing are below.