If you’ve ever wondered about the science behind those colourful deciduous trees every autumn, here’s your answer. Deciduous trees [leafy trees] shed in preparation for winter, but before losing their leaves, we see a colourful array of autumn tones replacing the vibrant greens of spring and summer. What makes this happen?
In the spring, when the snow melts and temperatures warm up, deciduous trees start to bud in preparation for renewal. With new growth, their green leaves fan out like solar plates, where chlorophyll [the chemical that makes leaves green] absorbs UV from sunlight to produce food. This tree food – carbohydrates like sugar and starch – sustains the tree through growth and can be stored. Trees need this stored food to break dormancy in the spring and carry on normal functions.
In the fall though, when our days get shorter and sunlight dims, environmental changes trigger a new process within the tree. Chlorophyll starts to break down and the leaves stop producing starch and sugars. As this cycle progresses, the green colour in the leaves disappears and the yellow, orange and red colours become visible. These tones were always there in the leaves – we just couldn’t see them under the green. At this time of year, some trees turn brilliant red like ornamental maples and sugar maples.
A few species of coniferous (needle bearing) trees also turn colour in autumn, including the stately Tamarack tree commonly found in the Kootenay region of BC. It is natural for most coniferous trees to shed their oldest needles this time of year. Usually needles closest to the trunk change from green to tones of copper, gold and red then drop off.
Whether you favour deciduous or coniferous trees, fall is the perfect time of year for leaf peeping – day tripping to view and photograph fall foliage. Our province has a lot of natural beauty and our wild and tame forests treat us this time of year with spectacular vistas. Take a walk in your local park and enjoy the view.
If you need tree services, or general seasonal landscaping maintenance, call the team at Pine Valley Tree Services and Landscaping. We have three offices in Kamloops, Chilliwack and Abbotsford to serve tree loving customers throughout Southwest BC.