But what drives ecologists to study the forest by looking up? “The morphology of a forest canopy tells us a lot about what lies beneath it,” Mina explains. Indeed, crucial processes for the very life of the forest depend on the light that manages to penetrate the trees; first and foremost: photosynthesis. It is no coincidence that beech forests, a species that is very competitive and dominant, are often devoid of undergrowth because their canopy is so closed, the shade that they create, limits photosynthesis and prevents the growth of other plants.
Conversely, when a canopy is very open, as in the case of larch forests, sunlight can filter in through the canopies and making the undergrowth lush. In other cases, however, if unshielded by trees, solar radiation can dry the soil out by increasing evaporation rates.
The amount of light that makes it through the forest canopy affects every component of the ecosystem, from bacteria to fungi, from plants to the animals that feed on them. For this reason, in reforestation or forest thinning plans, it is important to consider the morphology of the forest canopy. Otherwise, you run the risk of negatively altering the delicate balance between the different elements of these environments. For example, forest thinning operations should encourage an heterogenous environment in terms of lighting conditions, with areas of the undergrowth that are brighter and others that are darker. This would allow a wider variety of organisms to thrive in the undergrowth, from ones that prefer shade and moisture, such as some ferns, fungi and lichens, to those that prefer exposure to sunlight, such as many shrubs. “From this point of view, diversity is the key to a healthy, functioning forest ecosystem,” Mina concludes.