My nature notes remind me that I can expect the “best” fall foliage palette between Oct. 15-20. That can vary a bit each year, and since I lived in lower Carbon County, I based my observations on that. The elevation of the Pocono Plateau may see the peak foliage a few days earlier. I thought I would use this beautiful time of the year to explain a bit about leaves.

Our vascular plants (those with water carrying structures) rely on leaves to survive. Leaves contain chlorophyll (green pigment) that allows them to capture the sun’s energy. This process is called photosynthesis. Leaves’ main job is to make food for the plant to grow. Leaves capture sunlight and through their stomata (tiny holes in the leaf) they take in carbon dioxide from the atmosphere. With the energy captured from the sun, the carbon dioxide is combined with water to form sugars providing the leaf, stem, and roots food. We also know that leaves, as a by product of photosynthesis, release oxygen back into the atmosphere through the same stomata. This oxygen is needed for all animal and plant life on earth to survive.

A leaf is usually a blade (Lamina) attached to a stem/branch. The stalk-like part of the leaf is called the petiole. In autumn, cells form at the junction of the petiole and branch resulting in lack of water to the leaf and leaf color change. We are most familiar with tree leaves (maples, etc.) but cacti have adapted with green trunks and leaves that are modified into spines for protection from moisture seeking animals. Conifer leaves are modified into needles. They have less surface area and thus can remain on the branch over winter.

Leaves have an epidermis to protect them from the elements, much like our epidermis does. Leaves also have different edge margins that aid in identification. Some are toothed and some smooth or rounded. Maples or oaks have simple leaves (one leaf on a petiole) while sumac, hickories, or walnuts have compound leaves. Those leaves have multiple leaflets on a petiole.

As we approach my second favorite season of the year, autumn, our area is blessed with a wide array of leaf colors drawing many visitors to this region to enjoy the brief nature display. These fall leaf colors are attributed to the slow death of chlorophyll and when the green slowly disappears, the other pigments “show off.” The yellows of sweet birch are from carotenoids (yellow and oranges) while the reds of sumac or red maples are from the anthocyanins.

Get out there in the next few weeks to observe the gradual change in colors and the eventual shedding of leaves as the trees prepare for the harsher winter conditions. Enjoy what the Times News region has to offer us. We are fortunate.

Test Your Outdoor Knowledge: True/False: A white pine’s needles are held for 2 years before they are “shed.”

Last Week’s Trivia Answer: The majority of peregrine falcon nests are now on tall building ledges or under major bridges spanning large rivers/bays.