Hello, this is Peter from the Wild Bunch with our latest column.
The rain has set in and the temperatures are dropping. With this comes the change in colour, then fall, of leaves from deciduous trees. You can collect them up and stuff in a dark place to form leaf mould over the next few years.
The green leaf colour comes from a chemical called chlorophyll. The leaves look green because the chlorophyll absorbs mostly blue light, and some of the red, leaving the green wavelengths to be reflected back to us. The chlorophyll uses the blue light energy to capture CO2 from the atmosphere and make glucose. The plants are then able to use the glucose, together with other nutrients they get through their roots, to build wood, leaves and more chlorophyll. The whole process produces a surplus of oxygen, which is released into the atmosphere. It allows animals like us to eat the plants, absorb the glucose (and other chemicals) and ‘burn’ them in the oxygen to give us the energy we need to run around.
As autumn sets in and the cold means less activity, trees shed their leaves to preserve the moisture in their branches and trunk. They move into a dormant state, meaning they need less energy to stay alive. The chlorophyll is taken back from the leaf into the tree and as days further shorten and temperatures cool, auxin production in leaves starts to decrease. This triggers fractures, allowing the leaf to break away from the plant. The leaf is finally blown off by the wind or falls from its own weight.
Cold nights, dry weather and sunny days provide the best autumn colours and, as with so much in nature, there is a vast range of displays from the different plants we have in our gardens and the wild. It also means that when those colourful leaves fall, we can make use of them. Some examples of this include making leaf mould, or mulch, and even composting.
If you’d like to find out more about leaf mould and composting, perfect at this time of year, why not head along to our next Wild Bunch gathering on 16th November. We will be taking a look at the wonders of compost and what we should be doing in our own gardens to maximise its potential. We will also be discovering the many benefits of leaf mulch. To sign up, visit: https://www.frometowncouncil.gov.uk/wild-bunch/