Seeking Sustaining

Branching Out: More Reasons to Love Trees

Trees are poems that the earth writes upon the sky.” Kahlil Gibran

There are good reasons to be a tree hugger: they provide beauty, shade, and sometimes the bonus of fruit or flowers. More important is the miracle of a tree’s food-making process, photosynthesis, which involves absorbing carbon dioxide from the air and storing it in its wood. Trees and plants will store this carbon dioxide throughout their lives, helping to slow the buildup of this gas in our atmosphere that has been rapidly warming the planet.

Older, larger trees store a lot more carbon than younger trees, so it’s critical that in addition to planting new trees, we conserve and protect the ancient forests we still have.

Trees—from the tallest (the giant sequoia) to the dwarf willow (the smallest)– help us not just environmentally but emotionally and physically. Why? Because we move around more when we have access to parks, open spaces, and a leafy green yard. Those elms and maples and fir trees instill a sense of peace and awe in us.

There are more than three trillion trees on this planet; that’s about 422 trees per person. And talk about longevity!  A single beech tree can live for 400 years and produce 1.8 million beechnuts. Indeed, trees are so much more than inanimate lawn ornaments. A forest of trees is actually a superorganism of unique individuals; super because trees are linked to neighboring trees by an underground network of fungi resembling the neural networks in the brain. In one study, reported by The Nature Conservatory, a Douglas fir injured by insects was observed to send chemical warning signals to a ponderosa pine growing nearby.

The pine tree in turn produced defense enzymes to protect against the invaders. The trees were actually sharing “information important to the health of the whole forest,” researchers reported.  In other words, trees use their fungal network to communicate and warn other trees when danger is approaching. It’s something that the journal Nature has wryly dubbed the “wood wide web.”

But there’s more. Trees display a  collective intelligence similar to an insect colony.

In addition to warning each other of danger, trees appear to share nutrients to keep each other healthy. Trees in a forest are often linked to each other via an older tree called a “mother” or “hub” tree. Seedlings will link into the network of the old trees and benefit from that huge uptake resource capacity. The elder trees pass on carbon, nutrients, and water to the little seedlings at critical times in their evolution that help them to survive. Researchers have even studied what happens when a mother tree is being cut down. It will shuttle carbon immediately through the root systems, to its seedlings, giving them everything it has to give them a chance at survival.

Similarly, deciduous trees have been found to protect young conifer trees until they’re resilient enough to go after their own sunlight—and take their place in the sun. Another remarkable symbiotic forest relationship.

Trees are in two-way conversations, with electrical and chemical signals sent back and forth.  Edward Farmer at the University of Lausanne in Switzerland studies these electrical pulses and has identified a voltage-based signaling system bearing a striking resemblance to animal nervous systems. Although the accepted knowledge is that plants don’t have neurons or brains, it’s clear that even without nervous systems, trees on some level know what’s happening and even feel something akin to pain: when one is cut, it sends out electrical signals that initiate healing.

And trees worry about predators like animals do.

When a predator is feeding on little beech trees, for example, the tree is able to judge by the saliva on its leaves what animal it is and proceeds to pump poisonous substances into the leaves which alerts the surrounding beech trees. The animal’s saliva triggers warnings sent with electrical signals from tree-to-tree across the fungal underground network. The tree which the predator fed on warns the other nearby trees by gassing out repellant chemicals. And once a neighboring tree catches the chemical scent warning it sends out the poisonous substances to its own leaves.

More amazing, a tree can hear the frequency of water and potentially communicate that source and availability of water to another tree of the same species. According to the Uproar Foundation, trees in a forest, are always communicating with each other.

And they care about one another. Trees are not only very considerate in sharing sunlight and root systems, but when one dies, the companion tree usually dies soon afterward, because they are so dependent on each other.


Leaves are a rich source of calcium, magnesium, phosphorus, potassium, and more. The leaves of one large tree can be worth as much as $50 worth of plant food and humus. Pound for pound, leaves contain twice the mineral content of manure.  Here are three ways to honor our fallen leaves

  • Rake shredded leaves right into your garden, don’t cart them away.
  • Keep the leaves moist and let the fungi take over. After a while, the leaves will have disintegrated into a dark, sweet-smelling, soil conditioner that is high in calcium and magnesium which retains water. It serves as a great protective food for veggie and flower gardens and a great addition to potting soils.
  • Fallen leaves also provide wildlife, especially pollinators, with some winter cover. Bees, moths, butterflies, snails, spiders, and dozens of arthropods and pollinators overwinter in dead plant material for protection.

-Frances Goulart


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2 comments on “Branching Out: More Reasons to Love Trees

  1. Really well- written article! And I thought I had a reasonably solid subject knowledge! Ummm.. cheers to FG!

  2. Avatar photo

    Thanks for the nice comment. Yes, it was really interesting, right? I look at my own trees differently now.

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