09/11/2024
Nice to know the name of each leaf, around us
You autumn know 🍂
Tree leaves are beginning to change and here's why:
Chemical pigments in the leaf determine what color a leaf displays. Green is produced by chlorophyll. Yellow, orange, and red are from carotenoids. Reddish purple colours are due to anthocyanins. Tree species have different amounts of these chemicals in their leaves, so some species become red (Red Maples or Staghorn Sumac), and some are bright yellow (ash trees or Honey Locusts). Sugar maples can display them all!
As the days get shorter, the tree slows energy production, and chlorophyll breaks down. This allows the other pigments present to emerge. Leaves in more sunlit spots may turn red, while those in shadier locations will turn orange to yellow. That's why some trees can have a gradient of fiery colours over the season.
While some trees are changing a bit early despite the official start of fall on September 22, there are many factors that can affect autumn colours including light, moisture, and temperature so that no two falls are the same.
The most vibrant color displays occur when there is moderate precipitation through the growing season and warm, sunny fall days and cool, crisp nights. Higher than normal rainfall in Toronto may contribute to earlier changes in some trees.
Image: Common trees in Toronto, including non-native species like Norway Maple, and their typical fall colours.
