Amongst fruit-bearing cherry trees, there are two main types: Prunus avium (sweet cherries), which are the kind sold in produce sections for eating, and Prunus cerasus (sour cherries), which are the kind used in cooking and baking. Within those two types, there is a wide variety of species that all taste slightly different. However, the trees on which they grow, all being of the same family, bear many similar characteristics.
Observe the time of year in the area where you think you have spotted a cherry tree. Cherries flower early in the spring, then produce elongated clusters of pale, green, pendulous berries later on in the spring.
Observe the leaves of the tree. All cherry trees have rather large, shiny (not furry) green leaves. The bottom ones will be a medium-to-darker green, while up above, you will see the leaves start to turn a paler yellow. In fall weather, they will turn yellowish, with just a tinge of red. At all times of year, the leaves are an oblong oval shape with tiny serrations along their edges. While still on the tree, the leaves are simple and alternate along the branches. Cherries are deciduous, so they will lose their leaves once a season. If the tree is flowering, proceed to step 3. If the tree is fruiting, proceed to step 4.
Observe the flowers on the cherry tree. Rather than being purely ornamental, as with Japanese cherry trees (which do not bear fruit), these flowers have very long stamens poking out of smaller, ivory flowers. The combination is very good at attracting bees, which is a blessing to the trees because not all of them can self-pollinate. Flowers are elongated cylinders in shape.
Observe the fruit on the cherry tree. If it is late spring in your area, the fruits of a cherry tree are small, pale, green berries that hang from the tree's branches in pendulous clusters. Had you seen the flowers beforehand, you would note that the fruit is now hanging where the flowers previously were. Later in the season, heading toward late summer, you will notice the cherries getting larger and turning some shade of red. The exact shade and patterns on the skins vary by species of cherry. Consult your produce book for more information on specific species.
Observe the bark and the wildlife around the tree. Cherry tree bark is hard, dark brown, and not shaggy. The wood underneath is quite hard toward the bottom of the tree, which is why it is often used in wood crafts and building projects alike. Up toward the top, where the branches are still growing ever larger, the bark is much softer and can be damaged by weather. Cherry trees are hospitable places for a large variety of wildlife, including many insects (and pests), squirrels and birds. If the tree has begun fruiting, you may even be led to it by birds leaving evidence of their cherry-eating activities all around you.