Hi, I'm Meghan Field, an air quality specialist in California with a background in forestry and natural resources. I'm here today for About.com to answer the question: What are pinnately compound leaves on trees?Pinnately compound leaves refer to a leaf that is comprised of two or more leaflets on a common stalk or axis. Additionally, the veins within the leaf's lobes arise from several places along the central vein. You'll most often find these leaves on ash trees, walnut trees, pecan trees, and hickory trees. Let's take a closer look at pinnately compound leaves.This is a really good example of a pinnately compound leaf. It's compound because there are more than two leaflets coming off of the main stalk; and it's pinnate because they're coming off of either side of the main axis. Another feature of pinnately compound leaves are their pinnately veined leaflets, which have numerous veins coming off the main vein of the leaflet.Thanks for watching. To learn more, visit us on the web at About.com.