Ever wonder why the leaves change colours every fall?
- It does not occur because of frost. But, frost can disrupt the speed at which the leaves turn and halt colour transformation. Frost call kill the leaf and turn it brown.
Photo thanks to www.cottageblog.caSpring & Summer: trees are growing and turning green.
Fall: growth slows because of moisture levels, temperature, amount of stored energy in the roots, genetics. Systems begin to shut down as the tree prepares for winter dormancy
September 23rd (autumnal equinox): Days and nights are of equal length and thereafter the days are shorter and shorter. The sun's rays also become less direct and the air is cooler.
Autumn colour is a phenomenon that takes place within the leaves of a tree. Here's what happens:
- The lifelines between the leaves and the tree become blocked and the production of chlorophyll stops. The existing chlorophyll in the leaves slowly disappears as it is destroyed by sunlight.
- Throughout the summer, the green chlorophyll has been dormant, blocking out the other pigments, thus giving the leaves their green colour. Once the production of chlorophyll is halted, the leaves begin to show their true colours.
- As chlorophyll production ceases, other pigments become more dominant. Carotin helps with the orange colours and xanthrophyll is the yellow pigment.
- The leaves continue to change colour and reach their peak until the time just before the leaves fall. At the location where the leaf stem joins the branch of the tree, there is a separation layer. This is a layer of cells which gradually weaken, eventually causing the leaf to break off and fall.
Quick facts of leaf change:
- Colour change occurs on broad-leaved trees such as maple, oak, ash, and birch.
- These trees are also called "hardwoods" because most of them have wood which is quite hard, and "deciduous" because their leaves are shed each autumn.
- Trees that stay green all winter are "evergreen" or "coniferous" trees such as pine, spruce, hemlock, balsam, and cedar.
- Shedding their leaves actually protects the tree during winter. The leaves don't give off water (or transpire) when they are not on the tree, thus saving the tree from having the replace that water to keep the leaf alive.
Where in Muskoka is your favourite display of colour this year?
Cast your vote on the right or leave a comment!