The Hidden Life of Trees is full of fascinating facts about trees written in a folksy style by a German forester. Even information I’ve encountered before is given fresh meaning by the author’s enthusiasm and easy-to-grasp explanations. For example: “When trees are really thirsty, they begin to scream. . . you won’t be able to hear them, because this all takes place at ultrasonic levels.” Insects (and human survivalists) prefer to eat cambium, the "actively growing layer between the bark and the wood. . . . Cambium tastes like slightly resinous carrots, and it's very nutritious." (But only take from already downed trees to avoid harming the living). |
The reproductive success of forest trees is surprisingly abysmal. A mature beech tree can “produce a total of about 1.8 million beechnuts. From these, exactly one will develop into a full-grown tree . . . All the other hopeful nuts are either eaten by animals or broken down into humus by fungi or bacteria.” Those nuts that do grow into saplings will be guided and nurtured by older trees of the same species, primarily through a vast network of fungal threads entwined with their roots. “It appears that nutrient exchange and helping neighbors in times of need is the rule,” much like humans assisting each other in times of disaster. The author compares older trees nurturing young saplings to mothers who “pass along sugar and other nutrients. You might even say they are nursing their babies.” |
Trees toughen their trunks in response to “painful micro-tears that occur when the trees bend way over in the wind . . . Wherever it hurts, that’s where the tree must strengthen its support system. This is identical to the way humans build bone or bulk up their muscles.
Another similarity: “A tree contains almost as much liquid inside it as we do.”
And different kinds of trees are adapted to different micro-climates:
- Alders have air ducts in their roots allowing them to colonize swampy ground.
- Conifers “store essential oils in their needles and bark, which act like antifreeze [and they] cover the exterior of their needles with a thick layer of wax” so they can survive harsh winters with their needles intact.
- The leaves of quaking aspen help them grow fast in low light The leaves hang from flexible stems “and flutter in the breeze exposing first their upper and then their lower surfaces to the sun. This means both sides of the leaf can photosynthesize.”
Old growth forests are entirely different from those that have been clear-cut and replanted. One of the differences is the moss that often covers ancient trees. The “moss grows very slowly and takes decades to get established.” The algae in the moss captures nitrogen from the air in a form the tree can use. “Rain then washes this natural fertilizer down the trunks making it available to the roots.” Undisturbed old growth forests typically have very little underbrush (because of the shade cast by the ancient trees), which means they’re more resilient to forest fires than those that have been logged or otherwise disturbed by human activity, and more resistant to the effects of climate change. |
It’s much different in ancient old-growth forests: “There are more life forms in a handful of forest soil than there are people on the planet. A mere teaspoonful contains miles of fungal filaments.”