When many people buy a home, they are looking for trees on the property. Some even have an adjacent small woods like we do. We enjoy our trees in the spring. They bloom beautifully and give us shade all summer. I even enjoy the very first moments of fall when some color appears in them. But then it begins … the leaves start to fall, as they are now.
This falling action leads to a huge amount of work at our house. Almost daily for several weeks we are either blowing leaves or raking them. My husband received a gift for Christmas a few years ago that was a leaf blower that looks like a lawnmower. It has a lot more power than the hand-held type. I feel like he doesn’t always turn it up to its full potential, but it is a help in our project of clearing the yard of leaves. Just talking about this already makes me tired.
I realize there is a reason these leaves have to fall, so I decided to find out more about the process.
Some consider it to be the most incredible time of the year. For me, it just means outdoor work, sometimes in cold temperatures. I enjoy summer so much, and fall seems to be a reminder that dark, cold, winter is coming!
This whole thing starts with photosynthesis. Leaves typically produce their vivid hues of green from spring through summer into early fall through the constant creation of chlorophyll. As we all learned in 5th grade science, chlorophyll is the key component in a plant’s ability to turn sunlight into glucose, which in turn feeds the trees. Many millions of these chlorophyll cells saturate the leaves, ultimately making them appear green to the eye.
Without the presence of chlorophyll in the leaf, the bright colors – gold, red, yellow and brown – would be the natural colors seen year round.
Chlorophyll is not the only player in the fall leaf color game. Present in other leaves and trees are the compounds known as carotenoids and anthocyanins. As autumn days begin to get shorter, the production of chlorophyll slows, eventually coming to a halt and giving way to the ‘true’ color of the leaf. Now you’ve learned something, right?
Beta-carotene is one of the most common carotenoids present in most leaves. Strongly absorbing blue and green light, it reflects yellow and red light from the sun, giving leaves their orange hue.
Anthocyanin production increases dramatically with autumn. This protects the leaf, prolonging its life on the tree through the autumn season, and also provides the beautiful red color, my favorite.
We now know where the color comes from, but why do the leaves fall off in the fall?
It seems perennials, which include trees, must protect themselves in order to get through the harsh, freezing temperatures of winter. If trees do not shed their leaves, their soft vegetation would certainly freeze during winter time, damaging and no doubt killing the tree.
So, not only do we have to cope with ugly winter, but also so do the trees. In order to cope with winter temperatures, trees slowly close off the veins that carry water and nutrients to and from the leaves with a layer of new cells that form at the base of the leaf stem, protecting the limbs and body of the tree. Then water and nutrients no longer flow to and from the leaf. This enables them to die and weaken at the stem, eventually falling to the ground … which means I have to pick them up!
When leaves fall, it’s a recycling effort of sorts. They decompose back into the soil and make a rich humus, providing a source of nutrients for neighboring plants. That’s fine unless they are falling on grass. When they do, we have to remove them so the grass can live.
Some authors like Albert Camus get all romantic about fall and leaf color. He said, “Autumn is a second spring when every leaf is a flower.”
Another author said, “Autumn is number one – chilly weather, sweaters, Halloween and pumpkins, and all the bugs have returned to hell were they belong.”
My favorite may be from the author of the Maxine cartoons who said, “I love a fall breeze, especially when the leaves blow into the neighbor’s yard.”
(Melanie Behrens – firstname.lastname@example.org)
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