Most trees can be identified by studying their fruit or fruit seeds. Not all fruits on trees are edible to humans, but many fruits are food for animals. Pine and maple trees actually grow fruit; the pine cone is a fruit, as is the wing-like seeds that fall from maple trees. Learning to classify trees by their fruit is a process of research and practice. To start discovering the identity of trees, just a few tools are needed.
Borrow or buy books on tree identification. Purchase a tree identification field guide book from a garden center. Drop by the local Forest Service or Department of Natural Resources offices for pamphlets and inquire about where to find certain trees in your local area.
Take a walk on a nature trail or somewhere you will encounter a variety of trees. Visit a state park that has an abundance of trees. Tour a nursery to practice identifying trees. Stop by a fruit farm and ask questions about the different types of fruit and their trees.
Observe the trees fruit from all angles. Write down the color, size, texture and grouping of the fruit in the notebook. Notice if the fruit is soft and fleshy or enclosed by a hard shell. Take several photos of the fruit to help record its details.
Compare the notes on fruit characteristics with descriptions in books. Look at the field guide and match up the photos to the guide's illustrations. Narrow down the possibilities to a couple of trees. Study the fine details of the fruit and determine the tree's name.