How pleasant it feels on the senses to take a stroll in autumn. The temperatures are refreshing, the scents stimulating, and the marvellous yellow, orange, and red colours of deciduous trees and shrubs between the coniferous greens are pleasing to the eyes. But have you ever stopped to ask yourself why is it that the deciduous trees change colour before their leaves leave? The answer is that deciduous trees are one of our wild neighbours that are great at recycling.
Leaves are usually green because they contain a chemical called chlorophyll. This chlorophyll has an important job making food for the tree through the spring and summer. To build this chlorophyll the trees and shrubs need to pull in nutrients like phosphorous and nitrogen from the soils around it, which takes a lot of work. When fall arrives the daylight hours are getting shorter, and the trees are getting the signal that it is time to prepare for winter and shed their leaves. If they were to just drop their green leaves immediately all of the nutrients would go with them, and the effort the tree had put into pulling the nutrients out of the soil would be wasted. What is a tree to do?
One thing that they do is they start pulling the nutrients out of their leaves to store them in their roots and trunk instead. By storing them inside their toughened woody parts they are protecting them from the long cold winters making it possible to recycle them in spring. They also have to start breaking down the chlorophyll when they do this to ensure it stops making food. As the chlorophyll ‘leaves’ the green colour goes with it. However, the leaves don’t go clear because there are tiny amounts of other chemicals in the leaves that are other colours such as yellow, orange, red and brown. Depending on the type of tree different amounts of each of these colours will be present and the leaves will become whatever colour is in the highest quantity. There are even some leaves that turn purple. Without chlorophyll in the limelight all the other chemicals are given their own moment in the sun to be the beautiful colours we see in the fall leaves.
This whole recycling process of pulling in the nutrients before the leaves fall to the ground is called senescence. Without it trees would continuously get weaker over time. I encourage you to make like a tree this fall. Pull in the experiences from the year that have made you a better stronger person, the lessons that will serve you well in the future and store them in your core. ‘Leaf ’ all of the unnecessary bits out on a limb and watch them blow away in the wind. The good nutrients will hold you over whatever winters you will face, and come spring when you are ready, will let you blossom and ‘spring’ back into action.
Before you ‘fall’ into your next pile of leaves, take a moment to enjoy the wonderful colours that have finally been given their moment to shine through.
Laura Griffin
