What is the best way to save nature – to cordon off areas for parks and open space or to integrate conservation measures on working lands? Recent research makes a case for each of these approaches and has reignited a long-standing debate among scientists and conservationists.
I’m in a redwood forest in Santa Cruz, California, taking
dictation for the trees outside my cabin. They speak constantly, even if
quietly, communicating above- and underground using sound, scents, signals, and
vibes. They’re naturally networking, connected with everything that exists,
including you.
Biologists, ecologists, foresters, and naturalists
increasingly argue that trees speak, and that humans can learn to hear this
language.
Many people struggle with this concept because they can’t
perceive that trees are interconnected, argues biologist George David Haskell
in his 2017 book The Songs of Trees. Connection in a network, Haskell says,
necessitates communication and breeds languages; understanding that nature is a
network is the first step in hearing trees talk.
For the average global citizen, living far from the forest,
that probably seems abstract to the point of absurdity. Haskell points readers
to the Amazon rainforest in Ecuador for practical guidance. To the Waorani
people living there, nature’s networked character and the idea of communication
among all living things seems obvious. In fact, the relationships between trees
and other lifeforms are reflected in Waorani language.
In Waorani, things are described not only by their general
type, but also by the other beings surrounding them. So, for example, any one
ceibo tree isn’t a “ceibo tree” but is “the ivy-wrapped ceibo,” and another is
“the mossy ceibo with black mushrooms.” In fact, anthropologists trying to
classify and translate Waorani words into English struggle because, Haskell
writes, “when pressed by interviewers, Waorani ‘could not bring themselves’ to
give individual names for what Westerners call ‘tree species’ without
describing ecological context such as the composition of the surrounding
vegetation.”
Because they relate to the trees as live beings with
intimate ties to surrounding people and other creatures, the Waorani aren’t
alarmed by the notion that a tree might scream when cut, or surprised that
harming a tree should cause trouble for humans. The lesson city-dwellers should
take from the Waorani, Haskell says, is that “dogmas of separation fragment the
community of life; they wall humans in a lonely room. We must ask the question:
‘can we find an ethic of full earthly belonging?’”
Haskell points out that throughout literary and musical
history there are references to the songs of trees, and the way they speak:
whispering pines, falling branches, crackling leaves, the steady hum buzzing
through the forest. Human artists have always known on a fundamental level that
trees talk, even if they don’t quite say they have a “language.”
Photo by Jeffrey L. Bruce
Redefining
communication
Tree language is a totally obvious concept to ecologist
Suzanne Simard, who has spent 30 years studying forests. In June 2016, she gave
a Ted Talk (which now has nearly 2.5 million views), called “How Trees Talk to
Each Other.”
Simard grew up in the forests of British Columbia in Canada,
studied forestry, and worked in the logging industry. She felt conflicted about
cutting down trees, and decided to return to school to study the science of
tree communication. Now, Simard teaches ecology at the University of British
Columbia-Vancouver and researches “below-ground fungal networks that connect
trees and facilitate underground inter-tree communication and interaction,” she
says. As she explained to her Ted Talk audience:
I want to change the way you think about forests. You see,
underground there is this other world, a world of infinite biological pathways
that connect trees and allow them to communicate and allow the forest to behave
as though it’s a single organism. It might remind you of a sort of
intelligence.
Trees exchange chemicals with fungus, and send
seeds—essentially information packets—with wind, birds, bats, and other
visitors for delivery around the world. Simard specializes in the underground
relationships of trees. Her research shows that below the earth are vast
networks of roots working with fungi to move water, carbon, and nutrients among
trees of all species. These complex, symbiotic networks mimic human neural and
social networks. They even have mother trees at various centers, managing
information flow, and the interconnectedness helps a slew of live things fight
disease and survive together.
Simard argues that this exchange is communication, albeit in
a language alien to us. And there’s a lesson to be learned from how forests
relate, she says. There’s a lot of cooperation, rather than just competition
among and between species as was previously believed.
Peter Wohlleben came to a similar realization while working
his job managing an ancient birch forest in Germany. He told the Guardian he
started noticing trees had complex social lives after stumbling upon an old
stump still living after about 500 years, with no leaves. “Every living being
needs nutrition,” Wohlleben said. “The only explanation was that it was
supported by the neighbor trees via the roots with a sugar solution. As a
forester, I learned that trees are competitors that struggle against each
other, for light, for space, and there I saw that it’s just [the opposite].
Trees are very interested in keeping every member of this community alive.” He
believes that they, like humans, have family lives in addition to relationships
with other species. The discovery led him to write a book, The Hidden Life of
Trees.
By being aware of all living things’ inter-reliance, Simard
argues, humans can be wiser about maintaining mother trees who pass on wisdom
from one tree generation to the next. She believes it could lead to a more
sustainable commercial-wood industry: in a forest, a mother tree is connected
to hundreds of other trees, sending excess carbon through delicate networks to
seeds below ground, ensuring much greater seedling survival rates.
Foreign language
studies
Seedling survival is important to human beings because we
need trees. “The contributions of forests to the well-being of humankind are
extraordinarily vast and far-reaching,” according to the United Nations Food
and Agriculture Organization 2016 report on world forests (pdf).
Forests are key to combating rural poverty, ensuring food
security, providing livelihoods, supplying clean air and water, maintaining
biodiversity, and mitigating climate change, the FAO says. The agency reports
that progress is being made toward better worldwide forest conservation but
more must be done, given the importance of forests to human survival.
Most scientists—and trees—would no doubt agree that
conservation is key. Haskell believes that ecologically friendly policies would
naturally become a priority for people if we’d recognize that trees are masters
of connection and communication, managing complex networks that include us. He
calls trees “biology’s philosophers,” dialoguing over the ages, and offering up
a quiet wisdom. We should listen, the biologist says, because they know what
they’re talking about. Haskell writes, “Because they are not mobile, to thrive
they must know their particular locus on the Earth far better than any
wandering animal.” https://qz.com/1116991/a-biologist-believes-that-trees-speak-a-language-we-can-learn/
The gardener has a long, touchy-feely relationship with the
soil. As every good cultivator knows, you assess the earth by holding it. Is it
dark and crumbly, is there an earthworm or beetle in there, is it moist, and
when you smell it, are you getting that pleasant earthy aroma?
All these signs are reassuring, and have been through the
ages, but they are mere indicators of something much greater and infinitely
mysterious: a hidden universe beneath our feet. This cosmos is only now revealing itself as a result of
scientific discoveries based on better microscopic imaging and DNA analysis.
There is much still to learn, but it boils down to this: Plants nurture a whole
world of creatures in the soil that in return feed and protect the plants,
including and especially trees. It is a subterranean community that includes
worms, insects, mites, other arthropods you’ve never heard of, amoebas, and
fellow protozoa. The dominant organisms are bacteria and fungi. All these
players work together, sometimes by eating one another. The awareness of this biosphere should change the way
gardeners think about cultivating plants and heighten everyone’s understanding
of the natural world. In other words, don’t ever call it “dirt” again. The sheer vitality of it is mind-bending: A teaspoon of good
loam may contain a billion bacteria, yards of fungal strands, several thousand
protozoas and a few dozen nematodes, according to Jeff Lowenfels, a garden
writer based in Anchorage and co-author of “Teaming With Microbes.” This is, basically, how it works: Plants manufacture
carbohydrates through photosynthesis, but not just for themselves. They release
some of their carbon sugars into the soil, which causes the bacteria and fungi
to show up to feed. The bacteria crowd around the root zone, and the fungi form
vast networks of interlocking strands that often link one plant to another. The
bacteria convert nitrogen and other nutrients into forms the plants can use,
often by getting devoured by other microbes. The fungal strands, the mycelium, effectively increase the
root mass of its host plant by as much as a thousand times and transport a bevy
of goodies to the host plants, including phosphorus, copper, calcium and zinc.
There is also evidence that trees use this network to send signals to one
another if, say, leaf-eating pests have arrived. In his Ted Talk, mycologist Paul Stamets referred to
mycelium as “Earth’s natural Internet.”
Although some plant (and human) diseases are caused by
soil-borne fungi and bacteria, most of these microbes are beneficial and keep
the bad ones in check. The organisms assist in other ways, by increasing the
size of soil particles, which improves the ability of the soil to hold water
and air. Even in the middle of a city, the subterranean world is
thriving.
Scientists took almost 600 soil samples from across New
York’s Central Park and discovered a surprising diversity and richness. They
identified more than 120,000 types of bacteria and more than 40,000 species of
fungi, protozoa and arthropods. Among the unexpected findings: The microbial species were
the same, more or less, as those found in parts of the world with dramatically
different flora and climates from New York’s, including Antarctic cold deserts,
tropical forests and grasslands. There was a strong association between the diverse organisms
in each sample. “Unravelling these relationships will be critical to building a
more integrated understanding of below-ground ecology,” the researchers wrote
in a paper published by the journal for the British Royal Society. “Our work
highlights that most of the diversity found in soil remains undescribed.” Enough is known, however, to create a 21st-century subset of
farming known as regenerative agriculture. The farmers have discovered that if
you foster this biosphere, you don’t need expensive fertilizers because the
microbes repay the plants with nutrients. They also, for obvious reasons, avoid
pesticides that would kill this soil life. The farmers do as little soil digging as possible because
traditional tillage destroys the fungal networks and the desirable soil
structure. Cover crops keep the soil life happy between growing seasons. Advocates of this low-impact farming say it can restore soil
carbon lost by the historic conversion of forest and prairie to farmland and
help to mitigate greenhouse gases. In the 1990s, an Agricultural Research
Service scientist in Beltsville, Sara F. Wright, discovered a sticky coating to
fungal threads named glomalin that, it turns out, is a major reservoir for
carbon. Lowenfels says it’s also time for gardeners to adopt
practices that nurture the soil biosphere. To say he thinks deeply about this
subterranean world is an understatement. In addition to “Teaming With
Microbes,” he has written “Teaming With Nutrients.” His latest title is
“Teaming With Fungi,” which dwells on the type of fungi that directly associate
with plant roots. They are known as mycorrhizal fungi, and he’s a big fan of
adding them to his plants when they are installed, either as a spray or in
powdered form available from the garden center. “It works. My tomato plants are
bigger than the control, they’ve got more fruit on them, the plants are so
healthy,” he told me. “My carrots are unbelievable this year.” Some gardeners turn to compost tea to build soil microbes.
This is made by aerating sugars, compost and humic acids in non-chlorinated
water and then spraying the brew on plants and soil. Others are not convinced
that this is needed, though everyone agrees that the way to foster the soil
food web is to top-dress growing beds and lawns with organic matter such as
shredded leaves or finished compost. James Nardi, a biologist at the University of Illinois in
Urbana, offers this advice: “Work with your fellow non-human gardeners. I never
use synthetic fertilizers, and I never use pesticides.” Nardi’s 2007 book,
“Life in the Soil,” remains an excellent introduction to the subject. In the fall, he mixes horse manure with fallen leaves,
shreds the mixture and applies it as a mulch to his growing beds. “In the
spring, I have this lovely, spongy soil,” he said. Lowenfels shreds autumn
leaves on his lawn and lets the biosphere use them over the winter. The organic gardener’s mantra has never seemed more
appropriate. Feed the soil, not the plant. ● Earthworms: Earthworms (and other worms) play an important
role in the hidden biosphere. Most worm species in the garden were imported by
Old World settlers, and some worms in certain regions have caused a problem by
processing organic matter too efficiently. The latest culprit is a creature
called the Japanese crazy worm (Amynthas agrestis), which multiplies like, er,
crazy and damages the soil structure through mass feeding. It is long
established in parts of the Southeast but has spread recently to Wisconsin and
Illinois, where it is causing problems. But the European earthworms familiar to most gardeners are
helpful. Worms provide critical assistance to smaller organisms by
breaking down and incorporating leaves into the soil, so all may eat. Worm
castings are rich in nutrients, including calcium, nitrogen, phosphorus and
potassium. The most famous observer of earthworms, Charles Darwin,
estimated that they could add as much as 40 tons of casts per acre annually. ● Insects: Thousands of insects (and spiders) live in a
patch of soil. Some are considered pests by humans — Japanese beetle grubs,
termites and weevils, for example — but others are beloved or at least
beguiling and include the larvae of lightning bugs and cicadas. Dung beetles
convert animal waste into humus, a service we take for granted. Ants are the
most abundant soil insect. Although some species are pests or nurture pests
such as aphids, ants with their highly organized colonies are essential members
of the soil biosphere. They assist in the conversion of litter to humus, move
and mix large quantities of soil, and spread the seed of bulbs and other
desirable plants. ● Other arthropods: The more conspicuous of these include
millipedes and centipedes, as well as woodlice. Millipedes feed on plant debris
and microbes; centipedes eat other arthropods. Woodlice, or sowbugs, are
crustaceans that like soft plant debris and make quick work of green plant
material and newly fallen leaves. One of the most abundant, but barely visible, arthropods in
the soil are springtails. They are named for a tail-like structure that allows
them to jump when threatened. As many as a billion or more can live in an acre
of soil. Depending on species, they cycle plant debris or feed on fungi, algae
or other springtails. Mites are generally regarded by gardeners as pests, and some
are — sucking sap from plants and spreading disease. But the soil houses an
immense community of non-pest species that are essential to the cycle of life.
Half the known species of mites live in the soil, where they feed on decaying
plant litter. Nardi writes that they “set the stage for smaller decomposers
like bacteria and fungi to free most of the energy and nutrients stored in
those leaves.” Some mites are predatory and attack nematodes and other
small creatures. ● Nematodes: Nematodes are tiny wormlike creatures that have
traditionally been viewed in agriculture as serious pests that harm plants by
feeding on their roots. More recently, the view of nematodes has become more
nuanced because some species are now commonly used (and purchased) as predators
of garden pests such as slugs, vine weevils and white grubs, to name a few. In
truth, the world of nematodes is much greater and can only be imagined. Experts
believe there may be close to a million species, of which only a fraction have
been described scientifically. Some nematodes eat soil bacteria and fungi, while others
prefer to consume other soil arthropods and protozoa. Their value to the garden
is in converting nitrogen into a form that plants can use. ● Protozoa: Protozoa are microscopic creatures that live in
vast numbers in the film of water between soil particles. The most well-known
is the amoeba, but these microbes come in several forms, including species that
move with a single flagellum or with hair like cilia. They are the major predator of bacteria, and in consuming
them they release nitrogen and other nutrients to plants. Protozoa, in turn, are eaten by nematodes and other small
arthropods. ● Bacteria: Historically, bacteria have been associated with
germs. Some of the nastiest human diseases — anthrax, typhoid, tuberculosis and
syphilis, for example — are the result of bacterial infections. But we have
come to know too that our guts are full of beneficial bacteria and essential to
our health. The soil is the same way — the bad actors are outnumbered
and usually outwitted by the good ones. Healthy soil is loaded with bacteria,
and because they’re not very mobile, they tend to hang out in vast numbers on
and around the roots of plants, a zone known as the rhizosphere. There can be
as much as 100 times more bacteria around plant roots than elsewhere in the
soil, and with good reason. The plants feed them carbon sugars. The microbes
give back nitrogen.
● Fungi: Fungi break down organic matter, which is why you
will see mycelium strands in compost piles and under leaf litter. Two basic
forms of fungi form a symbiotic relationship with plants. One exists in
proximity to root tips and associates with hardwood trees and conifers. The
other penetrates the cell wall of the roots and is found in plants of the
domestic landscape — flowers, shrubs, grasses and vegetables.
The fungi grow tiny, fragile strands called hyphae. They are
a tenth the thickness of human hair, but there are so many of them that they
form a vast network, effectively extending the reach and efficiency of plant
roots. In her book “The Soil Will Save Us,” science writer Kristin Ohlson says
there can be as much as 320 miles of hyphae in a cubic foot of soil. At least
80 percent of the plants on Earth connect to these fungal partners.
“Gardeners need to know this stuff,” Lowenfels said. “A
thinking gardener is a better gardener.”
A dense carpet of woodland perennials. Thomas Rainer, a landscape architect, calls plants “social creatures” that thrive in particular networks. Credit Mark Baldwin
Thomas Rainer and
I have both been doing the botanical thing for decades; we know, and use, many
of the same plants — and even much of the same horticultural vocabulary. But
what he and I see when we look at a butterfly weed or a coneflower, or what we
mean when we say familiar words like “layering” or “ground cover,” is
surprisingly not synonymous.
It turns out I’ve
been missing what the plants were trying to tell me, failing to read botanical
body language and behavior that could help me put plants together in
combinations that would solve challenges that many of us have: beds that aren’t
quite working visually, and garden areas that don’t function without lots of
maintenance.
As we gardeners
shop the catalogs or the just-opening local garden centers with an eye to
finally “fixing” that bed out front that has never quite cooperated, I asked
Mr. Rainer, a landscape architect based in Washington, D.C., to lend us his 3-D
vision.
In his career, Mr. Rainer has
designed landscapes for the United States Capitol grounds, the Martin Luther
King Jr. Memorial and the New York Botanical Garden, as well as gardens from
Maine to Florida. He is an author with Claudia West of the 2015 book “Planting
in a Post-Wild World: Designing Plant Communities for Resilient Landscapes.”
He is a principal in the firm Rhodeside & Harwell, but will leave soon to
start a new firm with his wife, the landscape architect Melissa Rainer, and Ms.
West. He advocates an ecologically expressive aesthetic that interprets rather
than imitates nature.
Q. You visit a
lot of gardens, and probably hear from gardeners like me with beds that just
aren’t working. What’s the most common cause?
Traditional garden design often isolates plants, setting them “as individual objects in a sea of mulch,” Mr. Rainer said. “We place them in solitary confinement.” Credit Thomas Rainer
A. First, we have
to understand that plants are social creatures. Our garden plants evolved as
members of diverse social networks. Take a butterfly weed (Asclepias tuberosa,
named this year’s Perennial Plant of the Year by the industry
group the Perennial Plant Association), for example. The height of its flower
is exactly the height of the grasses it grows among. Its narrow leaves hug its
stems to efficiently emerge through a crowded mix. It has a taproot that drills
through the fibrous roots of grasses. Everything about that plant is a reaction
to its social network. And it is these social networks that make plantings so
resilient.
So if we think
about the way plants grow in the wild, it helps us understand how different our
gardens are. In the wild, every square inch of soil is covered with a mosaic of
interlocking plants, but in our gardens, we arrange plants as individual
objects in a sea of mulch. We place them in solitary confinement.
So if you want to
add butterfly weed to your garden, you might drift it in beds several feet
apart and tuck some low grasses in as companions, like prairie dropseed, blue
grama grass or buffalo grass.
Start by looking
for bare soil. It is everywhere in our gardens and landscapes. Even in beds
with shrubs in them, there are often large expanses of bare soil underneath.
It’s incredibly high-maintenance. It requires multiple applications of bark
mulch a year, pre-emergent herbicides and lots and lots of weeding.
The alternative
to mulch is green mulch — that is, plants. This includes a wide range of
herbaceous plants that cover soil, like clump-forming sedges, rhizomatous
strawberries or golden groundsel, and self-seeding columbine or woodland
poppies.
Intermingling plants can also foster more flowering plants in a smaller space.Credit Thomas Rainer
Q. If I want
to try to do it more as nature does, what am I aiming for? Where do I take my
cues?
A. The big shift
in horticulture in the next decade will be a shift from thinking about plants
as individual objects to communities of interrelated species. We think it’s
possible to create designed plant communities: stylized versions of naturally
occurring ones, adapted to work in our gardens and landscapes. This is not
ecological restoration, it’s a hybrid of ecology and horticulture. We take
inspiration from the layered structure in the wild, but combine it with the
legibility and design of horticulture. It is the best of both worlds: the
functionality and biodiversity of an ecological approach, but also the focus on
beauty, order and color that horticulture has given us. It’s possible to
balance diversity with legibility, ecology with aesthetics.
And it is a shift
in how we take care of our gardens: a focus on management, not maintenance.
When you plant in communities, you manage the entire plantings, not each
individual plant. This is a pretty radical shift. It’s O.K. if a plant
self-seeds around a bit, or if one plant becomes more dominant. As long as it
fits the aesthetic and functional goals. We can do much less and get more.
Q. Sort of
gives new meaning to the phrase “community garden,” doesn’t it?
A. Yes. And
plants each also have particular behavior — whether it wants to hang out with
other plants of its own species or not. So many gardening mistakes are a result
of not paying attention to this.
Q. You make
them sound like social animals, which makes me think I’ve been shallow,
objectifying plants — choosing among them for just another pretty face, instead
of reading their body language to get at their true nature.
A. One of the
most useful ideas that came out of our research was this German idea
of sociability, developed by Richard Hansen and Friedrich Stahl. They rank
a plant’s predilection to spread on a scale of 1 to 5. A low-sociability plant
is one that in the wild is almost always found by itself (Panicum virgatum, for
example, is almost always found by itself in a meadow). A high-sociability
plant is one that spreads into large colonies (Epimedium or Tiarella cordifolia
are Level 4 plants; Carex pensylvanica and Packera aurea are Level 5). You
arrange plants according to their sociability level: Plants of lower levels (1
and 2) are set individually or in small clusters. Plants of higher levels (3 to
5) are set in groups of 10 to 20-plus, arranged loosely around the others.
A meadow-like display of greenery on an urban deck designed by the HM White landscaping firm. Credit Aaron Booher
It sounds geeky,
ranking plants on a scale, but it’s useful because it informs which you should
mass, and which you should mingle. It’s why a mass of 50 echinacea (Level 2)
tends to flop. They’re just not meant to cover ground. But if you scatter a
handful of echinacea in a mass of prairie dropseed or sideoats grama, it will
look great.
For years, I
would pack together large grasses like switchgrass, or flowers like garden phlox
(both Level 1 plants) and wonder why they got rust or powdery mildew. But if
you find phlox in the wild, it will never have mildew. It’s growing out of a
lot of lower plants, so it gets good air circulation. This idea changed the way
I look at plants and pay attention to how they behave.
Q. I know that
nature doesn’t plop a 50-foot tree in a mowed lawn (or mow its lawn at all,
actually), so that’s not the winning design tactic. I also know that more
diverse layered designs are richer ecologically — and now you are saying they
are easier to manage, too. But how do I figure out how to fit the right plants
together?
A. We need to
start thinking about how, not what. So many garden books focus on what to
plant, but so few focus on how to arrange plants to fit together in ecological
combinations. When we fit our plants together like a tight jigsaw puzzle, the
maintenance goes way, way down. They start becoming resilient systems rather
than random objects.
To do this, we
need to pay attention to a plant’s shape. Its shape is often an indication of
where it grows in the vertical strata of a plant community. Upright plants with
low or minimal basal foliage like Joe Pye weed (Eutrochium) or spiky upright
plants like beargrass (Nolina bigelovii) have adapted to growing through other
plants. Horizontally spreading rhizomatous plants like Pennsylvania sedge
(Carex pensylvanica) or beach strawberry (Fragaria chiloensis) have adapted to
grow underneath others. You almost have to look at a plant from the vantage
point of a chipmunk to see its shape.
A grouping of plants by sociability: Foamflower (a very sociable Level 5) dominates, followed by wild ginger and trillium (Levels 2 to 3) and just a few ferns (more independent at Level 1). Credit John Roger Palmour
What I love about
this layering idea is that it gives gardeners flexibility. Those lower layers
should be very biodiverse: lots of different plants covering the ground and
providing stability. But diversity in this layer does not really look messy,
because most of these plants are growing underneath our taller ones, so you
don’t really see them.
In my garden, I
have a corner with dry shade where I have a handful of shrubs that screens a
busy road. Lately I’ve been adding white wood aster (Eurybia divaricata),
Appalachian barren strawberry (Geum fragarioides) and Pennsylvania sedge and
watching them fill the gaps. Upper layers, on the other hand, are the ones I
consider the “design” layers because they shape your impression of the
planting. You can arrange them naturalistically, or in neat clumps — whatever
style you like. That’s the flexibility: The order and legibility of the upper
layers combines with the diversity and functionality of the lower ones.
The really cool
thing is you can combine this layering idea with the sociability idea. Those
Level 1 and 2 sociability plants tend to be those taller upright plants you use
in the top layers of your garden because they like to grow through others. The
Level 3 to 5 plants tend to be your lower spreading ground-hugging species.
Q. So I am not
shopping for plants solely as decorative objects, but for plants with a purpose
— for instance, as a living mulch or a good companion to others. Of course none
of that, neither the “sociability” nor the plant’s layer, is on the plant
labels. A tag might say “for containers or landscapes” or that the plant is
“trailing” or “upright” or “mounding,” but that’s about it. What should the
label say to help me put plants together successfully?
A. My dream label
would describe things that are actually useful to understanding how it grows.
It would describe its shape, its root system (taprooted, deep fibrous roots,
shallow horizontal roots); its life span (a short-lived pioneer like columbine,
or a long-lasting lavender); its sociability level; its adaptation to stress
(quick-establishing, but short-lived ruderal species like Gaura lindheimeri or
Nassella tenuissima; a thuggish, fast-spreading competitor like Monarda didyma;
or a slow but steady stress-tolerator like Hosta or Calamintha). These are
really the factors that explain how it will grow in our gardens.
A. The Mt. Cuba Center, the Lady Bird Johnson Wildflower Center
and the California Native Plant Society
websites all have excellent information about how a plant grows in the wild and
what it grows with. But mostly, I think gardeners can get to know their plants
by going outside and getting reacquainted. Take a look at their shape, how they
spread and see what they are trying to show you. You can learn a lot.
“When I say, ‘Trees suckle their children,’ everyone knows immediately what I mean.” PETER WOHLLEBENCredit
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.”
Hurricane Sandy has changed the national conversation on
climate change. Unlike Hurricane Katrina, which much of the country was happy
to pin the blame for on New Orleans itself (“they shouldn’t have built there in
the first place!”), Sandy revealed climate change to be a growing threat to
nearly all coastal settlements. Formerly abstract warnings of growing
inundation risk, stemming from rising sea levels and increasing storm
frequency, suddenly became concrete and impossible to ignore. A new found sense
of vulnerability descended on coastal cities. In this light, urban design
cannot be dismissed as merely a luxury or an aesthetic consideration. The
discipline has taken on a new relevance and sense of urgency: cities,
particularly in coastal settings, must reconsider their built form in order to
adapt to radically altered environmental conditions. Three new books by Island
Press approach these issues with renewed sense of the value of the urban
design.
Entertaining and attractively designed, Alexandros
Washburn’s The Nature of Urban Design: A New York Perspective on Resilience
provides a fantastic introduction to the discipline of urban design for
non-designers. Washburn, the chief urban designer for New York City, uses that
city as case studies to explain what exactly urban designers do and why it
matters. He broadly defines urban design as “the art of changing cities,
guiding growth to follow new patterns that better meet our challenges while
improving our quality of life.” Of course, perhaps the biggest challenge facing
cities today is climate change, and The Nature of Urban Design uses Hurricane
Sandy to illustrate the need for adaptation, and how urban design can act as an
agent of change.
Washburn includes the suburbs in his definition of the city,
stating that the suburbs simply represent low-density cities, thus breaking
down the false city/suburb dichotomy. Washburn’s inclusion of the suburbs is
important because it allows him to expand the purview of urban design beyond
the city center to the entire metropolitan area. Urban design isn’t about
recreating a single notion of what the city is, but instead about adaptation
and improving living conditions, regardless of location within the metropolitan
region. Instead of seeking a rigid urban design toolkit, Washburn asks, “Is
there a form of the city that can survive new extremes of weather, that can
accommodate millions more citizens in dignity and prosperity, that can avoid
contributing more to climate change, and still be worth living in?”
He methodically walks us through why urban design matters,
how urban designers work, how urban design can be a catalyst for transformation
(using the High Line as a case study), and how it can lead to resilience in the
face of climate change. He discusses two strategies for resilience: mitigation
and adaptation. Mitigation means reducing greenhouse gases in order to prevent
adverse climate change, while adaptation involves reducing vulnerability to
projected climate change. With a certain degree of environmental change now
inevitable and a dramatic, global reduction in greenhouse gas production
seeming less and less likely, Washburn’s approach to resiliency is both
idealistic and practical.
Like Washburn’s book, The Hidden Potential of Sustainable
Neighborhoods: Lessons from Low-Carbon Communities, by Harrison Fraker, uses
global climate change to frame the new importance of urban design. Unlike
Washburn’s broad overview of the profession, however, Fraker’s is more narrowly
focused, using four European case studies to dig into the specifics of several
low-carbon urban design projects. Fraker describes how sustainability issues
such as energy efficiency have historically only been considered on the
building scale. The neighborhood scale, however, represents new opportunities
for carbon reduction. Fraker argues that the neighborhood scale has the
“potential to integrate the design of transportation, buildings, and
infrastructure while engaging the design of the public realm as part of the
system.” He refers to this as a “whole-systems approach,” where all urban
systems are considered together, greatly expanding the potential for
resiliency.
The Hidden Potential
of Sustainable Neighborhoods is about mitigation, citing examples of low-carbon
urban design projects. This does not mean, however, that Fraker is merely
presenting a series of utopian designs. Each of the examples in the book is
actually built, and Fraker looks back at commonalities between each project’s
implementation and subsequent performance. Furthermore, he applies the lessons
learned from the four European examples to sprawling, patchwork American
urbanism, describing the potential for infill opportunities. Fraker could have
spent more time addressing how to retrofit existing development rather than
concentrating on new development. Still, as he states, new models can catalyze
paradigm shifts, and we should appreciate his effort to translate European
lessons to messy American cities.
If The Nature of Urban Design is a layperson’s introduction
to urban design, and The Hidden Potential of Sustainable Neighborhoods is a
case-study resource for urban designers, The Guide to Greening Cities, by Sadhu
Aufochs Johnston, Steven S. Nicholas, and Julia Parzen, is probably of most
interest to urban planners. Like the other two books, The Guide to Greening
Cities lays out the challenge of designing cities in the face of climate
change. Johnston and his co-authors also refer to Hurricane Sandy, as well as
other climactic events, to establish the new urgency of resilient city design.
Instead of studying
the design of resilient cities, however, Greening Cities explores how city
leaders can implement new sustainability projects. Johnston and team state that
the book is “written from the perspective of green city leaders and champions
who are working inside city governments in North America and who have succeeded
in pushing forward innovative green projects.” Rather than emphasizing the
design of sustainability, Greening Cities walks through how city leaders can
make a case for, fund, implement, and subsequently monitor green projects. In
this way, The Guide to Greening Cities is a useful book for urban planners
wishing to increase the resiliency of their communities.
Cities are now faced with the task of both adapting to
inevitably changing environmental conditions and minimizing their contributions
to future climate change. The political, economic, environmental, and
technological challenges associated with this task are bewilderingly complex.
However, recent events such as Hurricane Sandy have shown inaction to be an
increasingly tragic prospect.
The complexity of designing for urban resilience requires a
broad cultural shift across many different disciplines. These three books
address the same problem of designing in the face of global climate change, but
do so for different audiences – the general public, urban designers, and urban
planners. With the consequences of global warming no longer abstract, hopefully
the sense of urgency that inspired these books will not abate.
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.
Biodiversity Hotspots The biodiversity hotspots hold especially high numbers of endemic species, yet their combined area of remaining habitat covers only 2.3 percent of the Earth's land surface. Each hotspot faces extreme threats and has already lost at least 70 percent of its original natural vegetation. Over 50 percent of the world's plant species and 42 percent of all terrestrial vertebrate species are endemic to the 34 biodiversity hotspots.
With proper planning and management, cities can retain substantial components of native biodiversity
Despite what is often commonly believed, fact is that many cities have high species richness. Several are even located within globally recognized "biodiversity hotspots"—areas with exceptionally high biodiversity (at least 1,500 endemic plant species) that have lost at least 70% of their original habitat area.
Some notable examples of cities with rich biodiversity are found on nearly all continents and latitudes - Berlin, Chicago, Curitiba, Kolkata, Mexico City, Montreal, Nagoya, New York City, São Paulo, and Singapore, to name but a few.
Many cities also contain protected areas within or just outside their borders that provide important contributions to biodiversity. In Cape Town, Table Mountain National Park, an iconic landmark extraordinarily rich in endemic plants and animals, is entirely surrounded by the municipality. In Mumbai, Sanjay Gandhi National Park—known for its dense semi-evergreen forests, 280-plus species of birds, 150 species of butterflies, and 40 species of mammals, including a small population of leopards—protects 104 square kilometers entirely within a megacity. In Stockholm, the National Urban Park comprises 2,700 hectares with high biodiversity, right in the city center.
Global Species Richness Centers of richness for mammals, amphibians and birds listed with the International Union for the Conservation of Nature.
Connecting fragmented ecosystems is also likely to increase ecological functionality as a whole and therefore to maximize the ecosystem services offered. There are diverse and innovative ways to connect natural ecosystems. Planting trees with overarching canopies can help small mammals, birds, and insects cross roads and highways. Roadside planting that mimics the multilayering of forests—for example, composite of tall trees, medium-sized trees, shrubs, and understory vegetation—can cater to a diversity of animal users. Ecolinks such as underground tunnels and vegetated overhead bridges can help connect natural areas. All of these efforts can complement the important roles played by protected areas in cities.
Many tools exist to help cities manage their biodiversity. One such tool is the City Biodiversity Index (or CBI, also known as the Singapore Index). This and many other initiatives can help cities conserve and manage their biodiversity.
AICHI TARGET 5: By 2020, the rate of loss of all natural habitats, including forests, is at least halved and where feasible brought close to zero, and degradation and fragmentation is significantly reduced.
Cities can help preserve forests and wetlands of critical biodiversity by ensuring the connectivity of existing and future protected areas. Managing footprints (best done at the provincial, state, or regional level) can also make a difference.
AICHI TARGET 12: By 2020 the extinction of known threatened species has been prevented and their conservation status, particularly of those most in decline, has been improved and sustained.
Campaigns by scientific institutions, zoos, museums, and aquaria— where city and regional authorities often have a managing interest—can raise critical attention and funds and provide technical assistance for the conservation of threatened species, even across the globe.
World Protected Areas Protected areas or natural parks are locations which receive protection because of their recognized natural, ecological and/or cultural values.
Cape Town
With a population of just under 3.7 million people and a land area of 2,500 square kilometers (0.2 percent of South Africa's total land area), Cape Town supports 50 percent of South Africa's critically endangered vegetation types and about 3,000 indigenous vascular plant species. Cape Town falls within the globally recognized biodiversity hotspot known as the Cape Floristic Region; of the 18 vegetation types in the city, 11 are critically endangered and 3 are endangered. Although this statistic in part reflects severe land-use pressure, it also disproves the common assumption that cities cannot have high levels of biodiversity. What's more, many of the plant species found in metropolitan Cape Town are endemic—found nowhere else on Earth.
São Paulo
São Paulo, Brazil, is the most populous city in the Southern Hemisphere and the third largest city in the world, with more than 11 million inhabitants. This megacity contains biodiversity from the Brazilian Atlantic Rainforest, a globally recognized biodiversity hotspot. Twenty-one percent of the city is covered by dense forest in various stages of ecological succession, but these remnants are under severe threat from the unrestrained occupation of both low-income housing and luxury condominiums. An impressive 1,909 plant species and 435 animal species have been recorded in the city, with 73 of the animal species endemic to the Brazilian Atlantic Rainforest. The city's Green Belt Biosphere Reserve, part of UNESCO's Mata Atlantic Biosphere Reserve, protects remnants of this rainforest as well as associated ecosystems.
City Biodiversity Index
The City Biodiversity Index, or CBI, also known as the Singapore Index on Cities' Biodiversity, is a self-assessment tool that encourages cities to monitor and evaluate their progress in conserving and enhancing biodiversity. More than 50 cities around the world are in various stages of testing the CBI and providing data for it. It currently comprises 23 indicators in three components: native biodiversity, ecosystem services provided by biodiversity, and governance and management of biodiversity. Stakeholders such as universities and civil society can assist in providing data. A platform for cities to share their experiences in applying the index has been particularly useful to cities considering using the CBI.
Other applications for the CBI have also surfaced. For example, information from it can be used in the decision-making and master planning of cities; it can assist policy- and decision-makers in allocating resources and prioritizing projects; good practices can be made into case studies for sustainable development; and some of the indicators can form the basis for calculating the economic value of biodiversity and ecosystem services. The CBI is also a useful public communication tool for city authorities. With ongoing refinement and improvement, it is continually becoming more valuable.
Singapore
By virtue of its geographical location, Singapore has a rich natural heritage. More than 10 ecosystems are found in this highly urbanized city— state of 5 million people. Although much of its biodiversity disappeared during the British colonization, Singapore still has a wealth of flora and fauna. Among the native species recorded are 2,145 vascular plants, 52 mammals, 364 birds, 301 butterflies, 127 dragonflies, 103 reptiles, 400 spiders, 66 freshwater fishes, and 255 hard corals. Between 2000 and 2010, intensive surveys found more than 500 species of plants and animals new to Singapore, of which more than 100 were new to science. Nestled in the heart of Singapore and not more than 15 kilometers from the busiest shopping areas are the Central Catchment Nature Reserve and Bukit Timah Nature Reserve. A network of parks and park connectors permeate the island, allowing easy access to varied habitats rich in plant and animal life.
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."
