by Tara Kender
As summer ends and we say goodbye to long sunny days, the beauty of fall takes center stage, bringing cooler weather and colorful leaves begin to drop.
Leaf drop is a form of self-protection as the weather becomes too cold for the leaves to function. During spring and summer leaves make food for the tree. They contain chloroplasts with green chlorophyll and yellow/orange carotenoids which ‘photosynthesize’ - a process that captures sunlight and creates carbohydrates.The leaves are green because the chlorophyll is at work.
As nights lengthen and temperatures drop, photosynthesis shuts down. With no chlorophyll, the yellow and orange pigments of leaves are revealed. Darker red leaves are the result of a chemical change: excess trapped sugar within the leaves creates red anthocyanins.
Deciduous trees form a scar between their leaves and stems to protect themselves from diseases and cold after the leaf drops. Most flowering trees form scars at different rates, in different parts of the tree, over several weeks. Each leaf falls off individually when its scar is fully formed.
Ginkgo trees in Brookdale Park
Photo credit: Tara Kender
But, a spectacular display is created by the Ginkgo biloba tree. In fall its leaves change from a deep green to a bright lemon color and then become a deep gold. And, uniquely it forms scars across all its leaves at once!
When the first hard frost of the season arrives, it finishes severing every leaf, and they fall to the ground in unison. This sometimes happens while the leaves are still green, but more typically occurs after the leaves have changed color. So don’t be surprised if you enjoy your beautiful bright golden ginkgo one day and your equally beautifully carpeted lawn the next.
Fallen Ginkgo leaves
Photo credit: Jacoba Coes
Ginkgos are amongst the oldest plants on earth, they, conifers, and cycads date back to dinosaurs. Imagine as our Brookdale Park ginkgos (located here) drop their leaves this fall, you are seeing something T Rex enjoyed as well!
Family Activity: Make Ginkgo leaf butterflies!
Click here for an easy video tutorial. Be sure to share your creations with us on Facebook or Instagram @brookdaleparkorg