1. Leaves can be very helpful in tree identification
Leaves can be very helpful in tree identification. Make sure you choose a leaf that is mature. Young leaves may not show all of the characteristics. Look at a range of leaves to assess the general leaf morphology of your specimen.

2. Leaves are usually green, flattened structures that are formed at a node as a lateral outgrowth of a stem. Try to find an axillary bud at the base of a leaf petiole in the node region of the stem. This area signifies the end of the entire leaf in both simple and compound leaves.
A simple leaf has only one blade or lamina associated with it. There are no leaflets.
In Singly compound leaves the leaf is sudivided into leaflets which attach to a central rachis. The rachis is continuous with the petiole which attaches to the node region of the stem, where the axillary bud will be found.
In doubly compound leaves the leaf is broken up into small leaflets which attach to a secondary rachis. This secondary rachis attaches to the central rachis. The central rachis is continuous with the petiole which attaches to the node region of the stem, where the axillary bud will be found.

3. Leaf arrangement pertains to the number of leaves attached to the node region of the twig and how these leaves are oriented relative to one another. Examine leaves at nodes located toward the base of first year twigs, where internodes are longest.

4. Presence of any of these characteristics will greatly facilitate identification.

5. The leaf blade or lamina is the flat part of the leaf
The leaf blade or lamina is the flat part of the leaf. Length is measured from where blade joins the petiole straight to the tip of the leaf (perpendicular to the width). Width is measured at the widest part of the leaf (perpendicular to the length). The petiole is the more or less round stalk that connects the leaf blade to the node region of the stem. Some species have very short petioles. Petiole length is measured from the point of attachment of the leaf blade to the node region of the stem.

6. The singly compound leaf blade is sudivided into leaflets which attach to a central rachis. The rachis is continuous with the petiole which attaches to the node region of the stem, where the axillary bud will be found. The leaflet blade or lamina is the flat part of the leaflet. Length is measured from where the leaflet blade joins the rachilla straight to the tip of the leaf (perpendicular to the width). The leaflet blade or lamina is the flat part of the leaf. Width is measured at the widest part of the leaflet (perpendicular to the length). The petiolule is the stalk extending from the base of the leaflet lamina to the rachis.

7. In the doubly compound leaf the leaflets are themselves subdivided into still smaller leaflets. The rachis is continuous with the petiole which attaches to the node region of the stem, where the axillary bud will be found. The leaflet blade or lamina is the flat part of the leaflet. Length is measured from where the leaflet blade joins the rachilla straight to the tip of the leaf (perpendicular to the width). The leaflet blade or lamina is the flat part of the leaf. Width is measured at the widest part of the leaflet (perpendicular to the length). The petiolule is the stalk extending from the base of the leaflet lamina to the rachis. In the case of doubly compound leaves use the "Mark OR" feature to set characteristics for both levels of leaflets.

8. The petiole is the more or less round stalk that connects the leaf blade to the node region of the stem. Presence of any of these characteristics can greatly facilitate identification.

9. Stipules of most tree species are present for one to two weeks in early spring, after which time the stipules abscise, leaving a stipule scar. Look for two small leaf-like structures, or two stipule scars on both sides of the leaf petiole or leaf scar at the node region of the twig. Use of a hand lens may be required to see stipule scars.

10. Venation refers to the pattern of arrangement of the veins (vascular bundles) within the leaf blade. These patterns are readily visible on the under side of leaves or if you hold them leaf up to a light or the sun.

11. The apex is the tip of the leaf blade.

12. The margin is the side of the leaf lamina.

13. The margin is the side of the leaf lamina.

14. The margin is the side of the leaf lamina.

15. The base of a leaf is the lower part of the leaf near where it attaches to the petiole.

16. Look at the top and bottom surface of the leaf lamina
Look at the top and bottom surface of the leaf lamina. Gently rub the leaf between your fingers to determine the texture of the top of the leaf lamina. Visually observe the effects that rubbing has on the color of the lamina. Observations can be facilitated by using a hand lens.