Here’s Why The Leaves Look So Lovely In The Fall
It’s a strange moment in life when one realizes there is beauty even in death, and the vibrant colors of autumn leaves as they fall from their source of nourishment is just one great example.
Leaves remain green most of the year due to chlorophyll, which absorbs the green and yellow wavelengths from the sunlight, reflecting back the green. It turns carbon dioxide and water into sugars that feed the tree.
As autumn progresses, trees photosynthesize less and begin to steal nutrients from their leaves in the process.
Eventually the trees cease making chlorophyll altogether, leaving the other colored pigments in the leaves – yellow flavonols and xanthophyll and orange carotenoids – visible to the naked eye once again.
Certain species of tree produce anthocyanins in the autumn, which produce red and purple hues, and protects the leaves from sunlight as well.
The tree re-absorbs the chlorophyll from the leaves before they fall, meaning that come spring, it won’t be starting from scratch.
Trees also produce a hormone called auxin year round, which keeps the leaves attached to their branches. But as autumn marches on the auxin production falls, trigging cells to form an abscission layer for form between where the leaf stalk joins the stem. There, it seals off the base of the leaf, meaning it can no longer absorb water or shed chemical waste products.
The leaf slowly dies, changing color as it loses the last of its chlorophyll, and is blown free by the wind or its own weight.
Weather patterns and soil nutrient levels can influence the color, as well as how long they remain on the tree or how quickly they drop.
They still contain nutrients once they’re on your lawn, so think about leaving them (if you don’t have a ton) or using them as mulch come spring instead of sending them to the dump.