Monday, September 25, 2017

What Trees Feel, How They Communicate...

Excerpts from a great book...

When you know that trees experience pain and have memories and that tree parents live together with their children, then you can no longer just chop them down and disrupt their lives with large machines.

Forests are superorganisms with interconnections much like ant colonies…

Together, many trees create an ecosystem that moderates extremes of heat and cold, stores a great deal of water, and generates a great deal of humidity. And in this protected environment, trees can live to be very old.

Every tree, therefore, is valuable to the community and worth keeping around for as long as possible. And that is why even sick individuals are supported and nourished until they recover.

In the symbiotic community of the forest, not only trees but also shrubs and grasses—and possibly all plant species—exchange information this way.

When trees grow together, nutrients and water can be optimally divided among them all so that each tree can grow into the best tree it can be.

A tree can be only as strong as the forest that surrounds it.

“A chain is only as strong as its weakest link.”

Scientists have determined that slow growth when the tree is young is a prerequisite if a tree is to live to a ripe old age.

There are more life forms in a handful of forest soil than there are people on the planet. A mere teaspoonful contains many miles of fungal filaments. All these work the soil, transform it, and make it so valuable for the trees.

While we are on the subject of erosion: it is one of the forest’s most dangerous natural enemies. Soil is lost whenever there are extreme weather events, usually following particularly heavy downpours. If the forest soil cannot absorb all the water right away, the excess runs over the soil surface, taking small particles of soil with it.

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.

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).

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 asking us to do.

Coniferous forests in the Northern Hemisphere influence climate and manage water in other ways, too. Conifers give off terpenes, substances originally intended as a defense against illness and pests.

Given this reciprocal relationship between trees and weather, forest ecosystems probably play an important role in slowing down climate change.

For ecosystems in Central Europe, regular rainfall is extremely important because water and forests share an almost unbreakable bond. Streams, ponds—even the forest itself—all these ecosystems depend on providing their inhabitants with as much stability as they can.

The forest floor acts as a huge sponge that diligently collects all the rainfall. The trees make sure that the raindrops don’t land heavily on the ground but drip gently from their branches. The loosely packed soil absorbs all the water, so instead of the raindrops joining together to form small streams that rush away in the blink of an eye, they remain trapped in the soil. Once the soil is saturated and the reservoir for the trees is full, excess moisture is released slowly and over the course of many years, deeper and deeper into the layers below the surface. It can take decades before the moisture once again sees the light of day.

In total, a fifth of all animal and plant species—that’s about six thousand of the species we know about—depend on dead wood.50 As I have explained, dead wood is useful because of its role as a nutrient recycler.

Sometimes dead wood is directly beneficial to trees, for example, when a downed trunk serves as a cradle for its own young. Young spruce sprout particularly well in the dead bodies of their parents. This is known as “nurse-log reproduction” in English and, somewhat gruesomely, as Kadaververjüngung, or “cadaver rejuvenation,” in German.

How often have we experienced warm spells in January or February without the oaks and beeches greening up? How do they know that it isn’t yet time to start growing again? We’ve begun to solve the puzzle with fruit trees, at least. It seems the trees can count! They wait until a certain number of warm days have passed, and only then do they trust that all is well and classify the warm phase as spring.

Beeches, for example, don’t start growing until it is light for at least thirteen hours a day. That in itself is astounding because to do this, trees must have some kind of ability to see.

The anticipated trajectory of a tree’s life can change at any time for any number of reasons. Its health depends on the stability of the forest ecosystem. It’s better if temperature, moisture, and light conditions don’t change abruptly because trees react extremely slowly. But even when all the external conditions are optimal, insects, fungi, bacteria, and viruses are always lurking, waiting for the chance to strike. That usually happens only when a tree gets out of balance.

The air in young pine forests is almost germfree, thanks to the phytoncides released by the needles. In essence, then, trees disinfect their surroundings.

Many of the companions that look after trees’ well-being in the forest (such as the microorganisms that make humus) are missing. Mycorrhizal fungi that help collect water and food are present only in low numbers. Urban trees, therefore, have to go it alone under the harshest conditions.

Silver birch bark has another surprise in store. The white color is because of the active ingredient betulin, its primary component. White reflects sunlight and protects the trunk from sunscald. It also guards the trunk against heating up in the warming rays of the winter sun, which could cause unprotected trees to burst. As birches are pioneer trees that often grow all alone in wide-open spaces without any neighbors to shade them, such a feature makes sense. Betulin also has antiviral and antibacterial properties and is an ingredient in medicines and in many skin care products.60 What’s really surprising is how much betulin there is in birch bark. A tree that makes its bark primarily out of defensive compounds is a tree that is constantly on the alert. In such a tree there is no carefully calibrated balance between growth and healing compounds. Instead, defensive armoring is being thrown up at a breakneck pace everywhere. Why doesn’t every species of tree do that? Wouldn’t it make sense to be so thoroughly prepared against attack that potential aggressors would breathe their last the moment they took the first bite?

Species that live in social groups don’t entertain this option because every individual belongs to a community that will look after it in times of need, warn it of impending dangers, and feed it when it is sick or in distress. Cutting back on defense saves energy, which the tree can then invest in producing wood, leaves, and fruit. Not so with the birches, which must be completely self-reliant if they are to survive. But they, too, grow wood—and indeed, they do so a lot faster—and they, too, want to, and do, reproduce. Where does all their energy come from? Can this species somehow photosynthesize more efficiently than others? No. The secret, it turns out, lies in wildly overtaxing their resources. Birches rush through life, live beyond their means, and eventually wear themselves out.

In the past few centuries, hunting has come to European forests as well, which, paradoxically, considerably increased the numbers of deer and wild boar. Thanks to massive feeding programs by hunters, who are mostly interested in increasing the number of antler-bearing stags, the population grew until today it is up to five times its natural level. German-speaking regions have one of the highest concentrations of herbivores in the world, so small beeches are finding it harder than ever to survive. And forestry is restricting their spread, as well.

Slowly but surely, fungi and insects are making their way across the Atlantic or the Pacific in imported lumber and establishing themselves in Europe.

The Asian long-horned beetle >> a threat. It probably traveled to Europe and other parts of the world from China in packing crates.

Habitats are defined by their features (water, terrain, topography) and by the local climate.

Trees act as huge air filters. Their leaves and needles hang in a steady breeze, catching large and small particles as they float by. Per year and square mile this can amount to 20,000 tons of material.

Trees trap so much because their canopy presents such a large surface area. In comparison with a meadow of a similar size, the surface area of the forest is hundreds of times larger, mostly because of the size difference between trees and grass. The filtered particles contain not only pollutants such as soot but also pollen and dust blown up from the ground. It is the filtered particles from human activity, however, that are particularly harmful. Acids, toxic hydrocarbons, and nitrogen compounds accumulate in the trees like fat in the filter of an exhaust fan above a kitchen stove. But not only do trees filter materials out of the air, they also pump substances into it. They exchange scent-mails and, of course, pump out phytoncides, both of which I have already mentioned.

Walkers who visit one of the ancient deciduous preserves in the forest I manage always report that their heart feels lighter and they feel right at home. If they walk instead through coniferous forests, which in Central Europe are mostly planted and are, therefore, more fragile, artificial places, they don’t experience such feelings. Possibly it’s because in ancient beech forests, fewer “alarm calls” go out, and therefore, most messages exchanged between trees are contented ones, and these messages reach our brains as well, via our noses. I am convinced that we intuitively register the forest’s health. Why don’t you give it a try?

Tree roots can breathe as well. If they didn’t, deciduous trees would die in winter when they discard their aboveground lungs. But the trees keep ticking over and their roots even grow a little, so energy must be produced with the help of the trees’ reserves, and for this the trees need oxygen. And that is why it is so awful for a tree if the soil around its trunk has been so compacted that the small air pockets in the soil have been crushed. The tree’s roots suffocate, or at least have difficulty breathing, with the result that the tree gets sick.

In 1981, the German journal Gartenamt reported that 4 percent of oak deaths in one American city happened because the trees were subjected to light every night.

Therefore, the color of organisms and objects is dictated by the color of the reflected light. And in the case of leaves on trees, this color is green.

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?

The color is the result of a metabolic disorder. Young developing leaves on normal trees are often tinged red thanks to a kind of sun block in their delicate tissue. This is anthocyanin, which blocks ultraviolet rays to protect the little leaves. As the leaves grow, the anthocyanin is broken down with the help of an enzyme. A few beeches or maples deviate from the norm because they lack this enzyme. They cannot get rid of the red color, and they retain it even in their mature leaves. Therefore, their leaves strongly reflect red light and waste a considerable portion of the light’s energy. Of course, they still have the blue tones in the spectrum for photosynthesis, but they are not achieving the same levels of photosynthesis as their green-leaved relatives. These red trees keep appearing in Nature, but they never get established and always disappear again. Humans, however, love anything that is different, and so we seek out red varieties and propagate them. One man’s trash is another man’s treasure is one way to describe this behavior, which might stop if people knew more about the trees’ circumstances.

The main reason we misunderstand trees, however, is that they are so incredibly slow. Their childhood and youth last ten times as long as ours. Their complete life-span is at least five times as long as ours.

It takes five hundred years from the time a national park is established to get to this point. Had large areas of an old deciduous forest that had seen only modest commercial use been put under protection, it would take only two hundred years to reach this stage.

There’s a common misconception about the appearance of old-growth forests in Europe, should they come to pass. Laypeople often assume that shrubby growth will take over the landscape and forests will become impenetrable. Where today the forests that predominate are at least partially accessible, tomorrow chaos will rule. Forest preserves untouched by foresters for more than a hundred years prove the opposite. Because of the deep shade, wild flowers and shrubs don’t have a chance, so the color brown (from old leaves) predominates on the natural forest floor. The small trees grow extremely slowly and very straight, and their side branches are short and narrow. The old mother trees dominate, and their flawless trunks stretch to the sky like the columns in a cathedral. In contrast to this, there is much more light in managed forests, because trees are constantly being removed. Grass and bushes grow in the gaps, and tangles of brambles prevent detours off the beaten path. When trees are felled and their crowns are left lying on the ground, the debris creates further obstacles. The whole forest presents a troubled and downright messy picture. Old-growth forests, however, are basically very accessible. There are just a few thick dead trunks lying on the ground here and there, which offer natural resting spots. Because the trees grow to be so old, few dead trees fall. Other than that, nothing much happens. Few changes are noticeable in a person’s lifetime. Preserves where managed forests are allowed to develop into old-growth forests have a calming effect on Nature and offer better experiences for people seeking rest and relaxation.

We are now discovering that animals share many human emotions. And not just mammals, which are closely related to us, but even insects such as fruit flies. Researchers in California have discovered that even these tiny creatures might dream. Sympathy for flies?

Not to put too fine a point on it, we use living things killed for our purposes. Does that make our behavior reprehensible? Not necessarily. After all, we are also part of Nature, and we are made in such a way that we can survive only with the help of organic substances from other species. We share this necessity with all other animals. The real question is whether we help ourselves only to what we need from the forest ecosystem, and—analogous to our treatment of animals—whether we spare the trees unnecessary suffering when we do this.

That means it is okay to use wood as long as trees are allowed to live in a way that is appropriate to their species. And that means that they should be allowed to fulfill their social needs, to grow in a true forest environment on undisturbed ground, and to pass their knowledge on to the next generation. And at least some of them should be allowed to grow old with dignity and finally die a natural death.

I, for one, welcome breaking down the moral barriers between animals and plants. When the capabilities of vegetative beings become known, and their emotional lives and needs are recognized, then the way we treat plants will gradually change, as well.

This is what this ecosystem achieves: the fullness of life with tens of thousands of species interwoven and interdependent.

Katsuhiko Matsunaga, a marine chemist at the Hokkaido University, discovered that leaves falling into streams and rivers leach acids into the ocean that stimulate the growth of plankton, the first and most important building block in the food chain. More fish because of the forest? The researcher encouraged the planting of more trees in coastal areas, which did, in fact, lead to higher yields for fisheries and oyster growers.

Ref: The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World by Peter Wohlleben

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