June 24, 2019

Do Trees Harbor a Hidden Life?

Trees have some capabilities you might find surprising – some that could even be considered surprisingly human. Examples of these are revealed in a recent book written by German Forester Peter Wohlleben, The Hidden Life of Trees. Read more to find out how trees “talk” to other trees, “help” other trees, and even exhibit forms of “courtesy”!

With all of the vast amount of knowledge that has been accumulated about science and our world over the past 200 years or more, we still have surprisingly little understanding of the processes and function of trees and other plants. According to Wohlleben, the greatest barrier to our comprehension of trees is the difference between the human and arboreal conception of time. Two of the photos accompanying this blog show some very old trees: The Big Oak in Thomasville, Georgia is documented at 338 years old. The photo above is of some Bristlecone Pine trees in the Colorado Rocky Mountains – 900 years old! It is not uncommon for undisturbed trees anywhere on Earth to live 500 years or more. Trees, therefore, have a “sense” of time that is far different from the 60 to 90-year human experience. We tend to equate the life of a tree to our own lifespan when the tree may live 3 to 10 times longer! Though they respond to the seasons just as we do, their processes are slower. A forest tree seedling may languish under the canopy of its parents for 50-100 years, waiting for the canopy to open up as an adjacent mature tree dies, allowing sunlight to flood into the space occupied by the seedling and allowing it to grow rapidly for the first time. So, the adolescence of a tree could span the entire life of a human! Think of “tree time” in terms of centuries, perhaps even millennia, and you have come much closer to understanding them.

Conversely, trees exhibit some hauntingly “human” traits:

  • Courtesy. If you have any doubts that trees are considerate of the space occupied by other trees, just take a look at the photo below, which also appears on the landing page of our website. Even with casual observation, one can easily see that each of the 4 Bald Cypress trees in the photo seeks out as much area as it possibly can to absorb energy from the sun, yet leaving a slight space between its canopy and that of the next tree in consideration of the space occupied by its neighbors. This phenomenon is not only true of similar species in a forest, but can also be seen in diverse forests as well.
  • Helpfulness. This trait, as that of courtesy, certainly goes counter to the preconceived notions we may have had about trees and plants in ruthless competition with each other, the Darwinian principle of “survival of the fittest”. On the contrary, recent research has shown the there is an intricate network in the soil composed of tree roots, fungal organisms, other microorganisms, and molecules that allow trees to communicate and exchange nutrients with microorganisms and even with other trees and plants. This web facilitates chemical and electrical pathways that allow a transfer of nutrition from a point of surplus to a point of need and an overall increase in efficiency for all of the participating players. One of the critical organisms in this network is a number of species of Mycorrhizal fungi: there can be miles of linked strands of these single-celled organisms in a single teaspoon of soil!
  • Communication and Self Defense. Many trees and plants have built in defense mechanisms. When a pest (insect or other animal) starts chewing on the leaf of a tree, the response may take one or more forms. For example, if a Giraffe chews on an Acacia tree on the plains of Africa, the leaves release aromatic compounds that travel downwind to other Acacia trees, allowing them to release compounds into their leaves that make them taste bad. Of course, the Acacia trees that are upwind don’t get this message, and their leaves are still tasty to the animals. The Giraffes know this from experience, and often actually browse upwind! In other cases, if an insect attacks a tree, a series of electrical impulses are sent through the plant so that defensive compounds can be produced. Remember, however, that the sense of time for a tree is slower – it’s not like we humans swatting a mosquito that is biting us. This electrical signal travels slowly, only about 1/3 of an inch per minute. It may therefore take an hour or more for the defensive compound to reach the site of the injury.

Sex is another great example for understanding the difference between tree time and human time. In his book, Wohlleben speaks of the sex life of the European Beech. See how this tree timetable stacks up with ours as humans:

  • The European Beech becomes sexually mature at 80-150 years of age.
  • Seed proliferation varies from year to year, but a single tree can put out 30,000 Beech Nuts every five years.
  • A mature tree will produce 1.8 million Beech Nuts in its 400-year lifespan.
  • Of these, exactly ONE will develop into a full-grown Beech Tree, and this is considered a high rate of success!

What does all of this say about the way that Downey Trees approaches Tree Care?

  1. We understand “Tree Time” and can quickly recognize the stress-causing factors that can shorten the normal life of a tree.
  2. Trees that are forced into the urban landscape either by removal of the surrounding forest during construction, or newly planted trees installed in soils devoid of living microorganisms, cannot function as part of a forest community and lack the mutual benefits of courtesy, helpfulness, communication, and self-defense discussed in The Hidden Life of Trees.
  3. Trees isolated in this way need the human touch to minimize stresses and compensate for the lack of a tree community. Examples of the human touch provided by Downey Trees include:
    • Proper pruning.
    • Pest and disease identification and management.
    • Restoration and maintenance of a “living soil” condition through Plant Health Care.
    • Monitoring of changing conditions so that tree care is provided as directed by the particular site, prevailing climate, and needs revealed by the tree itself.
    • Leaving the tree alone as much as possible so that it can develop on its own timeline.

Let us help you maintain your piece of the urban forest on “tree time”!

June 24, 2019