Amazing Trees By Angela Rieck

I have an amazing old tree in my backyard, it is a gnarled, pitted, dying tree. Arborists dismissively describe my favorite tree as a messy, junk, boxelder tree. Its trunk tells its story, tree cankers surround it as a reminder of the storms that lashed through it, the viruses, bacteria, insects, and mold that tried to destroy it and the lichen that coats its dead branches. And while it probably started out as a junk tree, it is now a magnificent, intricate work of art. I will keep it as long as I can.

After reading Peter Wollenben’s bestseller, The Hidden Life of Trees, I developed a special admiration for trees. Richard Power’s Pulitzer Prize winning novel, The Overstory expanded my appreciation.

Wollenben was the first to make the newest research about trees available to the general reader. Recent research has discovered that trees feed each other, especially their own kind, through the fungal mycorrhizal networks that are present underground throughout the earth. The fungi are connected to the trees’ roots, and they form a symbiotic relationship. The fungi supply the trees with carbon and mineral nutrients and the trees “pay” for this by giving them up to 30% of the sugar that they photosynthesize from sunlight. The fungi use what they need and transfer the rest to other trees through their network. 

This network connects to all trees in the forest. Research has shown that mature, healthy trees feed smaller trees, especially saplings who do not get enough sunlight to manufacture their own sugars. It also feeds trees that are not healthy. The small saplings that you see in a forest can be very old, some as old as 80 years, awaiting their time in the sun, which will occur when their parent dies. In the meantime, their trunks grow strong from the food supplied to them by their parent via the mycorrhizal network.

Trees communicate in a variety of ways. They communicate using pheromones or chemicals, warning other trees of pests, fungi, and other predators. Trees also communicate via a voltage signaling system through the mycorrhizal network at a 220 Hz signal that we cannot perceive. 

Trees have methods of responding to assaults. During an assault, trees produce a chemical that makes their leaves taste bitter to some invaders. A well-known example is the giraffe vs acacia tree. The wide-crowned umbrella thorn acacia is a favorite of giraffes. When a giraffe starts chewing acacia leaves, the tree notices the injury and emits a distress signal in the form of ethylene gas. Upon detecting this gas, neighboring acacias start pumping tannins into their leaves which can sicken or even kill giraffes. 

When elms and pines come under attack by leaf-eating caterpillars, they evaluate the caterpillar saliva, and release pheromones that notify neighboring trees of an attack. These pheromones also serve to attract parasitic wasps. The wasps lay their eggs inside the caterpillars, and the wasp larvae eat the caterpillars from the inside out.

Trees appear to be cooperative, by aiding trees that are sick, notifying other trees that are dangers, and even while dying releasing nutrients to neighboring trees.

The problem is that all of the research is on forests and not the trees that we have in our yards. Most scientists believe that this does not occur in trees that are planted in residential areas and trees planted after clear-cut logging.

But already, my box elder has beaten the odds, and I am hoping that scientists have yet to learn about our residential trees. I envision that healthy neighboring trees are feeding my old box elder through their own mycorrhizal network. I am hoping that this box elder will outlast me and provide the same wonderful focal point for the next homeowner.

Angela Rieck, a Caroline County native, received her PhD in Mathematical Psychology from the University of Maryland and worked as a scientist at Bell Labs, and other high-tech companies in New Jersey before retiring as a corporate executive. Angela and her dogs divide their time between St Michaels and Key West Florida. Her daughter lives and works in New York City.