Trees take life into the sky! Deciduous forests, like the one in which we are building our homes,
exhibit stratification or vertical layering of trees and other plants at different heights. Each layer is
characterized by particular types of plants and the organisms that utilize or interact with them; the
ecological conditions they create and the functions they perform. The uppermost layer is the
canopy, with the crowns, or tops, of trees being the interface between the land and the
atmosphere. The canopy layer receives the most sunlight and the most exposure to heat, winds,
and precipitation. The crowns of the tallest trees typically grow and close in toward one another,
with the amount of light that reaches the forest’s lower layers during spring and summer
depending on their density.
The canopy layer influences the forest and its environment in the following ways:
● Maximizes photosynthesis at the top of the canopy, with tree leaves taking in and sequestering
carbon and releasing oxygen in the process. This also helps to mitigate climate change.
● Buffers the effects of wind and precipitation, catching and slowing down rainfall, allowing it to
infiltrate into the soil, and helping to prevent erosion.
● Offers habitat that supports a great diversity of animals and other organisms. Branches, leaves,
and tree cavities provide shelter and food for birds (including predatory birds like the red-
tailed hawks we’ve seen regularly), mammals, insects, and reptiles. They also support the
growth of other plants and fungi.
● Shades and cools the forest below (maybe keeping us more comfortable on hot days!), and
maintains humidity and soil moisture for the lower levels of the forest. According to the US
Department of Energy, shading and transpiration (releasing of water vapor from leaves to the
atmosphere) can decrease general air temperatures by 6° F. or more. Temperatures nearest
the ground can be as much as 25° F. cooler than those above paved surfaces.
● Drops tree leaves in the fall, creating layers of leaf litter and humus, thus recycling nutrients,
and allowing light to reach the forest floor in springtime for plants in the levels below.
Indeed, the upper canopy has much to contribute to the beauty and ecological health of our
forested location.
Watch for the next installments in this series about forest layers, as winter ebbs and spring
approaches.