141
" As they photosynthesize, they produce hydrocarbons, which fuel their growth, and over the course of their lives, they store up to 22 tons of carbon dioxide in their trunks, branches, and root systems. When they die, the same exact quantity of greenhouse gases is released as fungi and bacteria break down the wood, process the carbon dioxide, and breathe it out again. The assertion that burning wood is climate neutral is based on this concept. After all, it makes no difference if it’s small organisms reducing pieces of wood to their gaseous components or if the home hearth takes on this task, right? But how a forest works is way more complicated than that. The forest is really a gigantic carbon dioxide vacuum that constantly filters out and stores this component of the air. It’s true that some of this carbon dioxide does indeed return to the atmosphere after a tree’s death, but most of it remains locked in the ecosystem forever. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
142
" Some species-like spruce-rely on timing. Male and female blossoms open a few days apart so that, most of the time, the latter will be dusted with the foreign pollen of other spruce. This is not an option for trees like bird cherries, which rely on insects. Bird cherries produce male and female sex organs int he same blossom, and they are one of the few species of true forest trees that allow themselves to be pollinated by bees. As the bees make their way through the whole crown, they cannot help but spread the tree's own pollen. But the bird cherry is alert and senses when the danger of inbreeding looms. When a pollen grain lands on a stigma, its genes are activated and it grows a delicate tube down to the ovary in search of an egg. As it is doing this, the tree tests the genetic makeup of the pollen and, if it matches its own, blocks the tube, which then dries up. Only foreign genes, that is to say, genes that promise future success, are allowed entry to form seeds and fruit. How does the bird cherry distinguish between "mine" and "yours"? We don't know exactly. What we do know is that the genes must be activated, and they must pass the tree's test. You could say, the tree can "feel" them. You might say that we, too, experience the physical act of love as more than just the secretions of neurotransmitters that activate our bodies' secrets, though what mating feels like for trees is something that will remain in the realm of speculation for a long time to come. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
143
" 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 "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
151
" It's a shame you can't transport entire beeches or oaks into the laboratory to find out more about learning. But, at least as far as water is concerned, there is research in the field that reveals more than just behavioral changes: when trees are really thirsty, they begin to scream. If you're out in the forest, you won't be able to hear them, because this all takes place at ultrasonic levels. Scientists at the Swiss Federal Institute for Forest, Snow, and Landscape Research recorded the sounds, and this is how they explain them: Vibrations occur in the trunk when the flow of water from the roots to the leaves is interrupted. This is a purely mechanical event and it probably doesn't mean anything. And yet?
We know how the sounds are produced, and if we were to look through a microscope to examine how humans produce sounds, what we would see wouldn't be that different: the passage of air down the windpipe causes our vocal cords to vibrate. When I think about the research results, in particular in conjunction with the crackling roots I mentioned earlier, it seems to me that these vibrations could indeed be much more than just vibrations-they could be cries of thirst. The trees might be screaming out a dire warning to their colleagues that water levels are running low. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
154
" Chlorophyll helps leaves process light. If trees processed light super-efficiently, there would be hardly any left over—and the forest would then look as dark during the day as it does at night. Chlorophyll, however, has one disadvantage. It has a so-called green gap, and because it cannot use this part of the color spectrum, it has to reflect it back unused. This weak spot means that we can see this photosynthetic leftover, and that’s why almost all plants look deep green to us. What we are really seeing is waste light, the rejected part that trees cannot use. Beautiful for us; useless for the trees. Nature that we find pleasing because it reflects trash? Whether trees feel the same way about this I don’t know, but one thing is for certain: hungry beeches and spruce are as happy to see blue sky as I am. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
156
" This ability to produce different compounds is another feature that helps trees fend off attack for a while. When it comes to some species of insects, trees can accurately identify which bad guys they are up against. The saliva of each species is different, and trees can match the saliva to the insect. Indeed, the match can be so precise that trees can release pheromones that summon specific beneficial predators. The beneficial predators help trees by eagerly devouring the insects that are bothering them. For example, elms and pines call on small parasitic wasps that lay their eggs inside leaf-eating caterpillars. As the wasp larvae develop, they devour the larger caterpillars bit by bit from the inside out. Not a nice way to die. The result, however, is that the trees are saved from bothersome pests and can keep growing with no further damage. The fact trees can recognize saliva is, incidentally, evidence for yet another skill they must have. For if they can identify saliva, they must also have a sense of taste. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
159
" A biologist from Leningrad, Boris Tokin, described them like this back in 1956: if you add a pinch of crushed spruce or pine needles to a drop of water that contains protozoa, in less than a second, the protozoa are dead. In the same paper, Tokin writes that the air in young pine forests is almost germfree, thanks to the phytoncides released by the needles. In essence, then, trees disinfect their surroundings. "
― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World
