Trees Aren’t Enough. We Need Forests.

Trees are a crucial piece of the climate crisis puzzle. They have an incredible ability to sequester and store carbon for long periods of time, so they’ve been identified as a key player in the climate fight. But to get that full effect, we need trees that live for hundreds of years because the bigger the tree, the more carbon it holds. Simply planting more trees is not going to have that same effect.

Location, Location, Location

We can set trees up for success by planting the right tree in the right place. Street trees, for example, can help cool neighborhoods and increase a street’s aesthetic value. But 50 is considered pretty old for a street tree. Some have proposed planting fast-growing species to sequester as much carbon as possible—but many fast-growing trees don’t live as long as our slow-growing oaks, which can live three or four centuries when planted in the right place.

So what’s the answer? In our region, the answer lies with our forests. Trees, it turns out, are not the solitary creatures they appear to be. In fact, the more we learn, the more we realize that a forest is more like a single complex organism than a bunch of individuals living in close proximity. In healthy forests, trees grow within a symbiotic community, supporting and watching out for one another, increasing each tree’s chance at making it to old age.

Tree Communities

Trees in a forest are connected with one another through an intricate web of fungi, which moves nutrients and information from one tree to the next via slow-moving electrical signals between roots. Even trees of different species cooperate with their neighbors, sharing limited resources and making space for one another in the canopy so that all of them can thrive. Like people, trees trade resources they have in excess for resources they lack or are unable to access.

Trees in a forest can also communicate with one another, warning neighbors of potential threats or impending danger. As an insect begins to eat the leaves of an oak tree, for instance, the tree will push chemicals into its leaves to make the taste unpleasant in an effort to limit the damage. But the tree will also use fungal pathways to warn surrounding trees of the insect’s presence, encouraging them to enact the same defense mechanism before they start getting eaten.

Forests and Climate Change

When you look around our built environments, you’re most likely to see a tree on the street, in a yard, or in a carefully manicured park. They give us shade and beauty. They shelter and feed wildlife. But it’s their cooperative habits that make trees such a powerful ally in the fight against climate change—and it’s only in forests that trees can truly live in communities, as they’ve evolved to do. This fact has important implications for trees’ ability to manage carbon.

When a tree dies, burns, or is cut down, the carbon stored within it needs to go somewhere. As a tree in a forest begins to die, it will transfer large portions of its carbon to offspring or neighboring trees, ensuring the health of its community and ensuring that the carbon remains stored. But when a tree dies alone, all the carbon it has sequestered throughout its life goes right back into the atmosphere.

This understanding of trees is incredibly important because it encourages us to think about the health of the entire forest community, not simply the growth and existence of singular trees. A fully functioning forest can sequester and store carbon long term, but a stand-alone tree will only be able to store that carbon for as long as that tree is alive. With our forests under significant threats from urbanization, invasive plants, pests, deforestation, climate change, and disease, it is more crucial than ever that we put our understanding to work in service of our forests.

Bottom line: What we need in the face of climate change is not simply more trees. We need healthy forests throughout our communities. In fact, trees are so important that supporting them is now a key part of our mission. Learn more about what the CGC and other local organizations are doing to support Cincinnati trees and how you can help.