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

— MOTHER SHIPS OF —
BIODIVERSITY
MOST ANIMALS THAT depend on trees don’t harm them. They just use the trunks or the crowns as
custom-built homes that offer small ecological niches, thanks to varying amounts of moisture and
light. Innumerable specialists find places to live here. Little research has been done, particularly in
the upper levels of the forest, because scientists need to use expensive cranes or scaffolds to check
them out. To keep costs down, brutal methods are sometimes employed. And so, in 2009, tree
researcher Dr. Martin Gossner sprayed the oldest (six hundred years old) and mightiest (170 feet tall
and 6 feet wide at chest height) tree in the Bavarian Forest National Park. The chemical he used,
pyrethrum, is an insecticide, which brought any number of spiders and insects tumbling down to the
forest floor—dead. The lethal results show how species-rich life is way up high. The scientist
counted 2,041 animals belonging to 257 different species.48
Tree crowns even contain specialized wetland habitats. When a trunk splits to form a fork,
rainwater collects at the point where the trunk divides. This minuscule pool is home to tiny little flies
that provide food for rare species of beetles. It’s more difficult for animals to live in trunk cavities
where water collects. The cavities are dark, and the murky, moldy brew that lurks there contains very
little oxygen. Larvae that develop in water cannot breathe in places like that—unless, of course, they
are endowed with snorkels, like the offspring of the bumblebee hoverfly. Thanks to breathing tubes
that extend like telescopes, these larvae can survive here. Bacteria are almost the only things stirring
in these waters, so they are probably the larvae’s food source.49
Not every tree is targeted by woodpeckers as a nesting site and doomed to gradual rot, and by no
means do all slowly waste away, offering many specialized species hard-to-find habitats as they do
so. Many trees die quickly. A storm might snap a mighty trunk, or bark beetles might destroy a tree’s
bark in a few short weeks, causing its leaves to wither and die. Then the ecosystem around the tree
changes suddenly. Animals and fungi that are dependent on the tree pumping a steady supply of
moisture through its veins or sugar to its crown must now leave the corpse or starve. A small world
has come to an end. Or has it just begun?
“Und wenn ich geh, dann geht nur ein Teil von mir.” “And when I go, only a part of me is gone.”
This phrase from a hit by German pop singer Peter Maffay could have been written by a tree. For the
dead trunk is as indispensable for the cycle of life in the forest as the live tree. For centuries, the tree
sucked nutrients from the ground and stored them in its wood and bark. And now it is a precious
resource for its children. But they don’t have direct access to the delicacies contained in their dead
parents. To access them, the youngsters need the help of other organisms. As soon as the snapped
trunk hits the ground, the tree and its root system become the site of a culinary relay race for
thousands of species of fungi and insects. Each is specialized for a particular stage of the
decomposition process and for a particular part of the tree. And this is why these species can never
pose a danger to a living tree—it would be much too fresh for them. Soft, woody fibers and moist,
moldy cells—these are the things they find delicious. They take their sweet time over both their meals
and their life cycles, as demonstrated by the stag beetle. The adult beetle lives for only a few weeks,
just long enough to mate. This animal spends most of its life as a larva, which slowly eats its way
through the crumbling roots of dead deciduous trees. It can take up to eight years for it to get big and
fat enough to pupate.
Bracket fungus is similarly slow. It gets its name because it sticks out from the dead trunk like a