The Hidden Life of Trees_ What They Feel, How They Commnicate

plants do this, not just trees. Even algae out in the oceans extract carbon dioxide from the atmosphere.
The carbon dioxide sinks into the muck when plants die, where it is stored in the form of carbon
compounds. Thanks to these remains—and the remains of animals, such as the calcium carbonate
excreted by coral, which is one of the largest repositories of carbon dioxide on earth—after hundreds
of millions of years, an enormously large amount of carbon has been removed from the atmosphere.
When the largest coal deposits were formed, in the Carboniferous period, carbon dioxide
concentrations were much higher—nine times today’s levels—before prehistoric forests, among other
factors, reduced carbon dioxide to a level that was still triple the concentration we have today.41
Where is the end of the road for our forests? Will they go on storing carbon until someday there
isn’t any left in the air? This, by the way, is no longer a question in search of an answer, thanks to our
consumer society, for we have already reversed the trend as we happily empty out the earth’s carbon
reservoirs. We are burning oil, gas, and coal as heating materials and fuel, and spewing their carbon
reserves out into the air. In terms of climate change, could it perhaps be a blessing that we are
liberating greenhouse gases from their underground prisons and setting them free once again? Ah, not
so fast. True, there has been a measurable fertilizing effect as the levels of carbon dioxide in the
atmosphere have risen. The latest forest inventories document that trees are growing more quickly
than they used to. The spreadsheets that estimate lumber production need to be adjusted now that one
third more biomass is accruing than a few decades ago. But what was that again? If you are a tree,
slow growth is the key to growing old. Growth fueled by hefty additions of excess nitrogen from
agricultural operations is unhealthy. And so the tried and tested rule holds true: less (carbon dioxide)
is more (life-span).
When I was a student of forestry, I learned that young trees are more vigorous and grow more
quickly than old ones. The doctrine holds to this day, with the result that forests are constantly being
rejuvenated. Rejuvenated? That simply means that all the old trees are felled and replaced with newly
planted little trees. Only then, according to the current pronouncements of associations of forest
owners and representatives of commercial forestry, are forests stable enough to produce adequate
amounts of timber to capture carbon dioxide out of the atmosphere and store it. Depending on what
tree you are talking about, energy for growth begins to wane from 60 to 120 years of age, and that
means it is time to roll out the harvesting machines. Has the ideal of eternal youth, which leads to
heated discussions in human society, simply been transferred to the forest? It certainly looks that way,
for at 120 years of age, a tree, considered from a human perspective, has barely outgrown its school
days.
In fact, past scientific assumptions in this area appear to have gotten ahold of the completely wrong
end of the stick, as suggested by a study undertaken by an international team of scientists. The
researchers looked at about 700,000 trees on every continent around the world. The surprising result:
the older the tree, the more quickly it grows. Trees with trunks 3 feet in diameter generated three
times as much biomass as trees that were only half as wide.42 So, in the case of trees, being old
doesn’t mean being weak, bowed, and fragile. Quite the opposite, it means being full of energy and
highly productive. This means elders are markedly more productive than young whippersnappers, and
when it comes to climate change, they are important allies for human beings. Since the publication of
this study, the exhortation to rejuvenate forests to revitalize them should at the very least be flagged as
misleading. The most that can be said is that as far as marketable lumber is concerned, trees become
less valuable after a certain age. In older trees, fungi can lead to rot inside the trunk, but this doesn’t
slow future growth one little bit. If we want to use forests as a weapon in the fight against climate
change, then we must allow them to grow old, which is exactly what large conservation groups are