It’s a beautiful time of year to go for a walk in the park, but do you know why?
Unlike you, trees don’t change colour in the fall for fashion’s sake — though they do look splendid with such command of the fall colour palette. What actually happens is they lose their green chlorophyll molecules, and the yellow and orange pigments beneath become visible. You knew that, though, or, maybe you did in grade six. But why does the chlorophyll disappear in the first place?
It maybe shouldn’t come as a surprise that it’s an efficiency thing—nature is nothing if not efficient. Rather than dropping the nutrient-dense green leaves they worked so hard to nurture, sucking the required nourishment up through the soil all summer (laborious work, to be sure), the trees recycle the energy. They “go green,” only in reverse.
Basically, they disassemble the photosynthesis machine from the inside out and store the useful bits (phosphorous and nitrogen) in twigs and branches for next spring. But during the disassembly, chlorophyll’s system is interrupted and it starts spitting out oxygen molecules that harm the recycling process. So, to minimize the damage and maximize the recovery of phosphorous and nitrogen to help grow next year’s leaves, the tree breaks down the chlorophyll, too, rendering it yellow or translucent.
And that’s why we wear yellow and orange turtlenecks in the fall…but what about those trees that turn red or purple?
Some trees, as if showing off, are able to recycle even more by putting up darker pigmented blockers that shade chlorophyll from the and prevent its wasteful behaviour during the recoup process; these trees can appear dark red or purple, and account for all the merlot-coloured elements in your fall wardrobe. Now you know.
For more, check out the video, below.