Astronomical Wisdom From the Forest: Where Does the Green Go?

Astronomical Wisdom From the Forest: Where Does the Green Go?

Have you ever wondered how the trees know that summer is drawing to and end? Here we are in mid-September and the daily highs are still climbing well over 80 degrees. It still feels like summer to you and me, yet the wise old trees know what is coming. The trees don’t rely as heavily on temperature to cue them in as much as we humans do, and their green leaves are already beginning to fade to yellow and flutter to the ground despite the muggy days.

So how DO they know? Think of these forest inhabitants as each having its own chemical atomic clock. They know the month of the year, the day of the month, the hour of the day and the second of the hour. The trees know because they keep very close records of how many milliseconds of sunlight fall on their leaves each day. It is this remarkable time keeping that signals to beautiful deciduous trees to shed their leaves, in preparation for hibernation. This is not a sudden or frivolous act, it is a strategic undertaking, crucial for survival.

The beautiful green leaves we so admire are repositories for chlorophyll, the substance plants produce to convert sunlight to food. As the chlorophyll does its job, it degrades and must constantly be replaced. All spring and summer long the trees keep busy producing a seemingly endless supply of chlorophyll and pumping it into their canopies but as the days grow slightly shorter and the sun trades in some of its shimmering brilliance for a softer amber glow the trees, magnificent beings that they are, make ready to conserve their resources.

By Jean-Pol GRANDMONT [GFDL or CC BY 3.0 ], from Wikimedia Commons

At the appropriate time they begin stowing away the ingredients that were formerly used to make the chlorophyll and that endless supply suddenly slows to a trickle. When this happens, the gorgeous green leaves fade to yellow, orange or red and finally the trees gently push them off the twigs. You see, it is much more than cold weather that triggers the changing of the leaves. The position of our planet on its trip around the sun is a key player in the dance of the seasons and signals to those tall beings of great astronomical wisdom we call trees that the cold weather is soon to arrive.

Here in Georgia the Tulip Poplar – properly called Tulipifera- is an iconic fall leaf and one of the first species to start turning each year. In honor of this annual event and as a thank you to our readers we have created a few special pairs of Tulipifera earrings in exotic Amaranth (purpleheart) wood. This small batch of earrings are available here until they are gone.

Henry Wischusen