Trees Have Social Networks, Too

“When I say, ‘Trees suckle their children,’ everyone knows immediately what I mean.” PETER WOHLLEBEN Credit Gordon Welters for The New York Times

 HÜMMEL, Germany — IN the deep stillness of a forest in winter, the sound of footsteps on a carpet of leaves died away. Peter Wohlleben had found what he was looking for: a pair of towering beeches. “These trees are friends,” he said, craning his neck to look at the leafless crowns, black against a gray sky. “You see how the thick branches point away from each other? That’s so they don’t block their buddy’s light.”

Before moving on to an elderly beech to show how trees, like people, wrinkle as they age, he added, “Sometimes, pairs like this are so interconnected at the roots that when one tree dies, the other one dies, too.”

Mr. Wohlleben, 51, is a very tall career forest ranger who, with his ramrod posture and muted green uniform, looks a little like one of the sturdy beeches in the woods he cares for. Yet he is lately something of a sensation as a writer in Germany, a place where the forest has long played an outsize role in the cultural consciousness, in places like fairy tales, 20th-century philosophy, Nazi ideology and the birth of the modern environmental movement.

Mr. Wohlleben traces his love of the forest to his early childhood, where he raised spiders and turtles. In high school, teachers painted a dire picture of the world’s ecological future, and he decided it was his mission to help. Credit Gordon Welters for The New York Times

After the publication in May of Mr. Wohlleben’s book, a surprise hit titled “The Hidden Life of Trees: What They Feel, How They Communicate — Discoveries From a Secret World,” the German forest is back in the spotlight. Since it first topped best-seller lists last year, Mr. Wohlleben has been spending more time on the media trail and less on the forest variety, making the case for a popular reimagination of trees, which, he says, contemporary society tends to look at as “organic robots” designed to produce oxygen and wood.

Presenting scientific research and his own observations in highly anthropomorphic terms, the matter-of-fact Mr. Wohlleben has delighted readers and talk-show audiences alike with the news — long known to biologists — that trees in the forest are social beings. They can count, learn and remember; nurse sick neighbors; warn each other of danger by sending electrical signals across a fungal network known as the “Wood Wide Web”; and, for reasons unknown, keep the ancient stumps of long-felled companions alive for centuries by feeding them a sugar solution through their roots.

“With his book, he changed the way I look at the forest forever,” Markus Lanz, a popular talk show host, said in an email. “Every time I walk through a beautiful woods, I think about it.”

Though duly impressed with Mr. Wohlleben’s ability to capture the public’s attention, some German biologists question his use of words, like “talk” rather than the more standard “communicate,” to describe what goes on between trees in the forest.

But this, says Mr. Wohlleben, who invites readers to imagine what a tree might feel when its bark tears (“Ouch!”), is exactly the point. “I use a very human language,” he explained. “Scientific language removes all the emotion, and people don’t understand it anymore. When I say, ‘Trees suckle their children,’ everyone knows immediately what I mean.”

Still No. 1 on the Spiegel best-seller list for nonfiction, “Hidden Life” has sold 320,000 copies and has been optioned for translation in 19 countries (Canada’s Greystone Books will publish an English version in September). “It’s one of the biggest successes of the year,” said Denis Scheck, a German literary critic who praised the humble narrative style and the book’s ability to awaken in readers an intense, childlike curiosity about the workings of the world.

The popularity of “The Hidden Life of Trees,” Mr. Scheck added, says less about Germany than it does about modern life. People who spend most of their time in front of computers want to read about nature. “Germans are reputed to have a special relationship with the forest, but it’s kind of a cliché,” Mr. Scheck said. “Yes, there’s Hansel and Gretel, and, sure, if your marriage fails, you go for a long hike in the woods. But I don’t think Germans love their forest more than Swedes or Norwegians or Finns.”

Mr. Wohlleben traces his own love of the forest to his early childhood. Growing up in the 1960s and ’70s in Bonn, then the West German capital, he raised spiders and turtles, and liked playing outside more than any of his three siblings did. In high school, a generation of young, left-leaning teachers painted a dire picture of the world’s ecological future, and he decided it was his mission to help.

He studied forestry, and began working for the state forestry administration in Rhineland-Palatinate in 1987. Later, as a young forester in charge of a 3,000-odd acre woodlot in the Eifel region, about an hour outside Cologne, he felled old trees and sprayed logs with insecticides. But he did not feel good about it: “I thought, ‘What am I doing? I’m making everything kaput.’ ”

Reading up on the behavior of trees — a topic he learned little about in forestry school — he found that, in nature, trees operate less like individuals and more as communal beings. Working together in networks and sharing resources, they increase their resistance.

By artificially spacing out trees, the plantation forests that make up most of Germany’s woods ensure that trees get more sunlight and grow faster. But, naturalists say, creating too much space between trees can disconnect them from their networks, stymieing some of their inborn resilience mechanisms.

Intrigued, Mr. Wohlleben began investigating alternate approaches to forestry. Visiting a handful of private forests in Switzerland and Germany, he was impressed. “They had really thick, old trees,” he said. “They treated their forest much more lovingly, and the wood they produced was more valuable. In one forest, they said, when they wanted to buy a car, they cut two trees. For us, at the time, two trees would buy you a pizza.”

Back in the Eifel in 2002, Mr. Wohlleben set aside a section of “burial woods,” where people could bury cremated loved ones under 200-year-old trees with a plaque bearing their names, bringing in revenue without harvesting any wood. The project was financially successful. But, Mr. Wohlleben said, his bosses were unhappy with his unorthodox activities. He wanted to go further — for example, replacing heavy logging machinery, which damages forest soil, with horses — but could not get permission.

After a decade of struggling with his higher-ups, he decided to quit. “I consulted with my family first,” said Mr. Wohlleben, who is married and has two children. Though it meant giving up the ironclad security of employment as a German civil servant, “I just thought, ‘I cannot do this the rest of my life.’” The family planned to emigrate to Sweden. But it turned out that Mr. Wohlleben had won over the forest’s municipal owners.

So, 10 years ago, the municipality took a chance. It ended its contract with the state forestry administration, and hired Mr. Wohlleben directly. He brought in horses, eliminated insecticides and began experimenting with letting the woods grow wilder. Within two years, the forest went from loss to profit, in part by eliminating expensive machinery and chemicals.

Despite his successes, in 2009 Mr. Wohlleben started having panic attacks. “I kept thinking, ‘Ah! You only have 20 years, and you still have to accomplish this, and this, and that.’” He began therapy, to treat burnout and depression. It helped. “I learned to be happy about what I’ve done so far,” he said. “With a forest, you have to think in terms of 200 or 300 years. I learned to accept that I can’t do everything. Nobody can.” He wanted to write “The Hidden Life of Trees” to show laypeople how great trees are.

Stopping to consider a tree that rose up straight then curved like a question mark, Mr. Wohlleben said, however, that it was the untrained perspective of visitors he took on forest tours years ago to which he owed much insight.

“For a forester, this tree is ugly, because it is crooked, which means you can’t get very much money for the wood,” he said. “It really surprised me, walking through the forest, when people called a tree like this one beautiful. They said, ‘My life hasn’t always run in a straight line, either.’ And I began to see things with new eyes.”

http://www.nytimes.com/2016/01/30/world/europe/german-forest-ranger-finds-that-trees-have-social-networks-too.html?_r=0 

Botanists Gear up for Second Phase of Red List Project

Not so mighty: The IUCN Red List in July reported that a third of all conifers are under threat due to logging and disease.

Museum scientists are planning the next stage of a study to reveal the global destruction of plant life. It is the second phase of a collaborative project between the Museum, The Royal Botanic Gardens, Kew and the International Union for the Conservation of Nature (IUCN), which began in 2005. The information from the study feeds into the Red List Index, an online barometer of animals, plants, insects and fish at risk of extinction, produced twice-yearly by the IUCN.

The first phase, completed in 2010, was a desk-based analysis of some of the six million plant specimens in the Museum's herbarium collection and the seven million at Kew to monitor the status of the world's plants.

The specimens have been collected over hundreds of years by thousands of botanists, including Charles Darwin, and are preserved for study in the collections. They provide data to show where certain plants have been living in the past.

Darwin meets Google Earth

The team then used satellite imagery, including from Google Earth, to compare the historic data with what can be seen living on the ground and used to illustrate which habitats have been reduced or destroyed altogether. Assessments of different areas then allowed them to create a map of hotspots of plant diversity and threatened species.

The researchers concluded in 2010 that more than 20 per cent of the world's plants, or one in five, are threatened with extinction, with a further 10 per cent classified as near threatened.

Truth on the Ground

The second phase of the project, for which funds are being sought, involves going out into the field, or ground-truthing, to measure the desktop assessment with the situation on the ground, to plot decline and target certain areas for conservation. Some plants on the Red List haven't been seen for 150 years.

Other species have never been seen on the ground and are only known from the scientific paper where they are first described. There have even been cases of plants newly discovered in a collection that have already gone extinct in the wild.

Loss of Habitat

The overwhelming threat to natural habitat is anthropogenic (caused by human activity), through habitat conversion to agriculture, for development or mining, or through the introduction of invasive species.

'A good example of this is the volcanic island of St Helena in the south Atlantic, where several species of a shrub, Trochetiopsis, were indigenous', said Museum botanist Neil Brummitt, who has worked on the project from the beginning.

'Local deforestation for fuel and ship-building, as well as for agriculture, disturbed the habitat, which was then put under further pressure by the introduction of goats by the Royal Navy to feed sailors stationed on the island. The goats fed on the endemic species, causing havoc to the island's ecosystem. '

Biodiversity Jigsaw

The latest Red List, published last month, assessed 71,576 species of animals, plants, insects and fish and reported that 21,286 are under threat.

'If you can't preserve everything, it becomes a value judgement deciding what to preserve,' Brummitt said. 'We're losing a large proportion of the world's biodiversity without knowing what the knock-on effect will be on other species, such as birds and insects. We're losing pieces of a biodiversity puzzle.'

Eighty per cent of calories consumed by people around the world come from just 12 species of plants.

'Plants provide the foundation for the entire world's ecosystems,' Brummitt said. 'Biodiversity is important because it's essential not to rely on a handful of species to provide the ecosystem services most developed countries still depend on, for food, shelter and clean water.'

Bees Hop Between Green Roofs

Green roofs aren’t just isolated islands of nature. They’re also stepping stones for flying insects such as bees, scientists have found.

While it’s clear that green roofs can boost biodiversity in cities, scientists didn’t know whether these patches could act as connected habitat. So a team studied 40 green roofs in Zurich, Switzerland, with plants ranging from succulents to meadow species. From May to September 2010, the researchers caught 48,084 ground beetles, spiders, weevils, and bees from nearly 500 species on the green roofs and at corresponding green spaces on the ground.

The team then looked for links between the arthropod communities and factors such as the size of the roof, the amount of flowers, and distance to the nearest green roof or other habitat. For ground beetles and spiders, the local environment had a big influence on the species present. But for flying bugs such as bees and weevils, “connectivity was by far the most important variable,” the authors write in Ecology.

These roof-hopping insects may help pollinate plants, the team notes. And connected populations are more likely to bounce back from disturbances.

Source: Braaker, S. et al. 2013. Habitat connectivity shapes urban arthropod communities: The key role of green roofs. Ecology doi: 10.1890/13-0705.1.

http://conservationmagazine.org/2013/09/bees-hop-between-green-roofs/

Daylighting Takes Off as Cities Expose Long-Buried Rivers

There's likely an underground stream in your city, but it may soon be seeing the light.

Uncovering buried streams has had huge impacts in places as diverse as Seattle, Washington, Kalamazoo, Michigan, and even Seoul, Korea—improving local water quality, providing habitat for fish and birds, and turning neglected parking lots and roads into public parks that boost neighbors' property values and can revitalize entire cities. And city planners everywhere are starting to take note.

In Yonkers, the fourth largest city in New York State, officials are a third done with a "daylighting" project—a term for the opening up of underground streams (see "11 Rivers Forced Underground"). In addition to exposing a waterway that had long been covered, the effort has already sparked plans for a new minor-league ballpark and new housing.

"I credit the city and the people who ... figured that having a nice river in a downtown was something that was, economically, really good," said Ann-Marie Mitroff, director of river programs for Groundwork Hudson Valley, an environmental justice nonprofit.

But why are all these streams covered at all? Flash back more than a hundred years. In many urban areas around the world, small streams were just getting in the way. You couldn't build on top of them, and the rapidly growing populations in many cities were throwing all their sewage into open water.

Often, engineers found that the simplest solution was to bury the streams, routing the water into pipes and paving over the top. In Yonkers, "the Army Corps of Engineers put a parking lot on top of it, which everybody thought was progress," Mitroff said. [Editor's note: A spokesperson for the U.S. Army Corps of Engineers says there are no records of the agency covering streams in Yonkers, and said the Corps would not have had jurisdiction to do so. They pointed to local authorities as most likely responsible; National Geographic has been unable to confirm that.]

In some cities, more than 70 percent of streams have been paved over. In many cases, city residents don't even know that there are buried waterways under their feet.

Now, new research and a desire to revitalize urban cores is leading to a host of daylighting projects. Uncovering buried streams has been proposed in San Francisco, Baltimore, and Detroit, as well as in smaller urban areas nationwide.

Uncovering streams can help reduce flooding. When it rains in a "natural" watershed, soil and plants absorb the water. When it rains onto a parking lot that drains into an underground pipe, the potential for flooding is much larger.

According to a new report from advocacy nonprofit American Rivers, released July 17, urbanization increases the likelihood of floods getting worse. One study found that paving over 25 percent of a watershed could turn a formerly rare severe flood into a twice-a-decade event. When more than 65 percent of a watershed is paved over, those so-called "hundred-year-floods" could hit every year.

Watch the Money Flow

Early daylighting projects, like Arcadia Creek in Kalamazoo, focused on the economic benefits of bringing streams back to the surface. Turning a parking lot into a 3/4-mile-long (1.2-kilometer-long) strip of Arcadia Creek in downtown Kalamazoo created a park that hosts five annual festivals and generates $12 million in annual tourism dollars.

But Arcadia Creek isn't really a creek. According to a report from the Virginia Tech Water Resources Research Center, the Arcadia Creek project and similar ones do "not resemble streams per se, but rather canals with surrounding parkland ... [the streams] are very controlled water channels [with] concrete-lined basins."

In Seoul, a $384 million project daylighted three miles (five kilometers) of stream that has most of its water pumped in from a river seven miles (11 kilometers) away. Both parks have been successful in boosting the economic value of the surrounding land and bringing locals a little closer to nature.

Digging up a stream isn't cheap. In Hutchinson, a town in rural Kansas, daylighting just three city blocks of Cow Creek cost more than $4 million, including relocating four buildings out of the new floodplain. But compared to the cost of unearthing, replacing, and reburying the city's aging pipes, building a new downtown park was an easy choice.

Not all daylighting projects need to be the centerpiece of an urban revitalization project. In Washington, D.C., the District Department of the Environment (DDOE) is undertaking small daylighting projects of a few hundred feet (around a hundred meters) in upper Northwest D.C., which is more suburban than urban, despite its location within the nation's capital.

Each project will create a small amenity for immediate neighbors, but they are mostly intended to mitigate local flooding and improve water quality. "Water in a pipe is not exposed to biological processes that break down pollution," said Steve Saari, watershed protection specialist with DDOE.

A recent EPA study found that streams exposed to sunlight are up to 23 times more efficient at processing nitrogen, which left unprocessed can cause dead zones where fish cannot survive.

Return of a "Living Stream"

In Yonkers, the uncovered stream is "a living stream," Mitroff says. The first reopened part of the stream (which opened in 2012) is already filled with fish and "fairly good-size" American eels, up to 18 inches (46 centimeters) long. "It's remarkable," Mitroff said.

In D.C., only months after daylighting a tributary to Rock Creek, "we've seen a lot more birds, and a lot more unusual birds," said Saari. And, he added, "we had frogs. It was incredible."

http://news.nationalgeographic.com/news/2013/07/130730-daylighting-exposing-underground-rivers-water-urban-renewal/