A brief lesson in autumn leaves

By Brandie Majeau
The vibrant and colorful leaves of autumn are associated with a certain feeling, a particular
scent, and a spectacular feast for the eyes. However, they also play a crucial
role in sustaining the life of trees. Deciduous trees, characterized by their leaves
changing color in the fall, shed their foliage as part of their seasonal cycle. In contrast,
evergreen trees, with their needle-like leaves, retain their green color year-round to
carry on the process of photosynthesis even during the winter months.
During most of the year, deciduous tree leaves appear vibrant green due to
chlorophyll, a pigment that enables them to harness energy from sunlight through
photosynthesis. This energy is then transformed into sugars, which nourish the tree and
support its growth. As the seasons transition from summer to fall, the air becomes
crisper, the days grow shorter, and the tree’s vibrant green leaves transform into a
breathtaking display. The reduced sunlight triggers a breakdown of chlorophyll in the
leaves, allowing the hidden yellow and orange pigments to emerge. Certain trees
undergo a chemical change, resulting in the production of new pigments called
anthocyanins, which give rise to the stunning red hues seen in leaves as seen in oak
trees. The autumn landscape, with its unique blend of colors, is a sight to behold,
offering a sense of awe and wonder wherever it is viewed.
As the season progresses, the leaves begin to fall. Trees start to create a
protective barrier between the leaves and their branches as the weather changes. They
extract as many nutrients as possible from the leaves, but the leaves would not survive
the winter and would leave the trees vulnerable to damage if they remained. Once the
leaves are severed from the fluid in the branches, they detach and descend to the
ground.
Visiting the local library is a great place to start if one wants to learn more and
delve into the amazing science behind the natural world. Or visit local nature or natural
museums.