Young pecan tree leaves often look the same as the leaves of many other types of trees, making it a challenge to identify them while the plants are immature. The leaves often resemble those from members of the hickory tree family. The long leaves from pecan trees more than one-year old feature lots of leaflets, a good sign that the leaves may come from a pecan cultivar. The leaves of pecan trees also look a bit like fern leaves, although several other nut trees also produce fern-like greenery.
Note the location of the tree. Pecan trees primarily grow in warmer climates in the south from Texas to the Atlantic Ocean.
Measure the leaves to determine if they grow from 12 to 20 inches in length, a sign that the leaves may come from a pecan tree.
Confirm that the leaves look dark green on one side and pale green on the underside -- another clue they may come from pecan cultivars.
Crush the leaves and immediately sniff them. Pecan leaves produce a strong aromatic odor.
Determine if the leaflets appear alternately on the stem rather than directly across from one another. All pecan leaves produce alternate leaflets on their leaves.
Count the number of leaflets on the leaf. Leaflets consists of the smaller leaves that make up the entire leaf. New pecan trees may only contain simple leaves during the first year, but as the plants mature, the number of leaflets increases. Most pecan trees at least a few years old feature leaves with between nine and 13 leaflets. A few pecan leaves feature as many as 17 leaflets.
Examine the shape and size of the leaflets. Pecan trees produce leaflets that appear small and lance-shaped with tips that tend to curve. Leaflets grow from 4 to 8 inches in length.
Look for serrated, sharp edges on each leaflet. Pecan leaflets have serrated margins.