Archive for 2018

All About Bark

Friday, July 20th, 2018

rough and smooth bark


Anyone who regularly reads this blog knows that I am in love with trees.  They are marvelous beings in a great many ways.  And most recently, I have been musing on a particular aspect of trees–their bark.

I wonder why there are so many different types of bark.  Why do some trees, like the beech, have smooth bark?  Why do others, like oaks and hickories, have thick, furrowed bark?

Then there is color.  Why are most trees some shade of brown or grey?  And why do some trees have bark of a different color, like the white of a birch or the green of a palo verde?

Of course the overall answer is that the 60,000+ tree species in the world have all evolved to adapt to particular, local environmental conditions.

But I am curious to know more about the differences among trees’ bark, and how the bark of each species is uniquely suited to help that species thrive. So I decided to do a little research, and it turns out that bark is as incredible as the rest of the tree!

All Bark Does It

Despite its many different looks, bark serves  the same essential functions for all trees.

Bark protects a tree’s internal living systems from the outside world–from extremes in temperature, from loss of moisture, from fire and rainstorms, from disease, and from insects that could damage or even kill a tree.

Bark is more than what we see.  Just inside a tree’s outermost surface is a layer of inner bark that also plays an essential role.  Called the phloem, the inner bark circulates nourishment throughout the tree.  This ‘food’ is the product of photosynthesis–that process by which leaves take in sunlight and carbon dioxide and transform them into sugars that feed the tree.

The Smooth and Rough of Bark

All young trees have smooth bark.  And some species keep that smooth bark their entire lives.  Other species, however, develop rough, furrowed bark with age.  As a tree grows–as that thin layer called the cambium just inside the inner bark adds living wood to the tree every year (think tree rings)– pressure is exerted outward against the bark.  And it is how the bark responds to this pressure that determines whether the outer bark will remain smooth or will become rough and furrowed.

For example, beech bark responds to the internal pressure of growth by expanding.  The bark of a beech tree grows slowly to accommodate the new, growing wood inside.  At the end of a beech tree’s life, it has the very same bark it started out with, only more of it.

But rough-barked trees, like oaks and hickories, respond to pressure from the growth taking place inside by splitting into vertical pieces.  And as the outer bark splits into sections, a new layer of bark forms inside.  This process is repeated again and again as the tree continues to grow, resulting in the rough, deeply furrowed bark of older trees.

Smooth vs Rough: Different Benefits

Smooth bark can help a tree with photosynthesis.  While photosynthesis is typically the leaves’ job, smooth bark is dotted with small openings that take in carbon dioxide from the air to generate additional food for the tree.  In times of defoliation, due to disease or drought, this added photosynthesis can help a tree stay healthy.  Bark photosynthesis tends to peak in early spring and late fall, when there are no leaves shading the bark.

If you’ve ever wondered about the dark, horizontal lines on birch bark, or the diamond-shaped marks on an aspen trunk, or the raised, white dots on spicebush bark, these are all lenticels, openings that allow carbon dioxide to enter the tree.

Rough bark offers a different kind of protection.  Trees with rough bark are much better defended against fire than are trees with smooth bark. All over the world, rough-barked trees in especially fire-prone areas develop even thicker bark than they do in less fire-prone regions.  The bark of Scots pines and black oaks, for example, are extra thick in regions where fire occurs frequently.

And the ridged, furrowed bark’s greater surface area contributes to an even temperature inside the tree.  The thickness of rough, furrowed bark also provides protection against injury from outside.

Bark Color

Most bark is some shade of brown or grey, which experts say is largely because the many chemical substances in the bark, when combined, create a dark color.  Think of the brownish color that results when different colors of paint are spread over one another.

But what about trees with white or green bark?

The white bark of the birch reflects the sun’s rays.  While one might think that a tree of the cold north, like the birch, would do better to absorb, rather than reflect, the sun’s warming rays, that actually is not the case.  If birch bark were to absorb the sun’s rays on a sunny winter day, that warming, followed by the extreme cold of the northern winter night, could cause rapid fluctuations in the temperature of the birch’s cambium.  Such fluctuations between warm and very cold could result in cell death and severe injury to the tree.  So white birch bark serves a protective role.

birch bark 

And what about the greenish color of the palo verde? Unlike the bark of many smooth barked trees that plays a secondary role in photosynthesis, the bark of the palo verde is the tree’s primary source of photosynthesis.  Palo verde bark is filled with chlorophyll, which makes it green.  Photosynthesis through the palo verde’s bark accounts for two-third’s of the tree’s photosynthesis, with the leaves playing a much lesser role in the process.

palo verde


Other Protective Features of Bark 

Certain trees, smooth and rough barked-trees alike, ‘exfoliate’ or shed bark.  Consider the peeling birch.  Or the shagbark hickory with its long, vertical strips of bark that seem to hang loosely from the trunk.  Or the sycamore that sheds hunks of curled bark.


This exfoliation may serve different functions for different trees.   The horizontal curls visible on a peeling birch prevent mosses and lichens from establishing themselves on the bark, preventing the clogging of lenticels, which would interfere with photosynthesis.

But when it comes to how the shagbark hickory and sycamore benefit from exfoliation, I could find no solid explanation, only speculation.  Tree experts believe that exfoliating may rid trees of aphids, harmful fungus, and bacteria.

Bark’s chemical composition often plays a protective role too.  Birch bark, for example, is high in volatile oils.  These oils make birch bark so waterproof and resistant to decay that tubes of old birch bark can sometimes be found on the forest floor, even after the wood inside has rotted.  And the bark of black cherry exudes a bitter almond scent which deters browsing animals that might damage the tree.  Oak bark contains tannin, an astringent substance that is toxic to insects.

Barking Up the Right Tree

Tree bark is truly incredible.  Just like trees themselves.–April Moore





An Ode to the Appalachian Trail

Monday, May 14th, 2018
photo by Robert McCaw

photo by Robert McCaw

What I wanted for my birthday in mid-April was to take a hike on the Appalachian Trail with my husband and son.  So that’s what we did.   And with most of the trees still bare, it was the wildflowers along this southern Virginia portion of the Trail that stole the show that day.   They were taking full advantage of that brief period during which it is they–not the leafy tree tops–who are getting most of the sunshine.  Soon most of the wildflowers would be in shade.  Now was their time.

The most prominent of the wildflowers we saw that day was bloodroot.  Scores of the white flowers poked out of the leaf litter along the Trail.  The many-petaled flower gets its name from its red-colored sap, that can be seen by tearing a leaf, and from its red-colored root.

As we walked, I found myself musing about how dearly I love the Appalachian Trail.  Over the last 40+ years, I have savored many day hikes on short sections of the Trail–mostly in Virginia, but also in Tennessee, Maryland, West Virginia, Pennsylvania, Vermont, and New Hampshire.  And wouldn’t I love to sometime hike the entire 2,200 miles of the AT, all the way from Springer Mountain, Georgia, to Mount Katahdin, Maine!

In fact, I vividly remember the moment I first learned of the Trail’s existence.  I was a high school junior, and one day in English class, the subject of the AT arose.  How, I don’t know, nor do I remember what was said.   But I clearly remember the thrill of suddenly knowing that such a trail exists.   Immediately, I longed to get out there in the forest, to hike on that trail for day after day after day, to live in the forest for the time it would take me to hike the 2,000 mile long trail.

Years later, I moved to Washington, DC from Florida, and  I had ample opportunity to get out onto the AT for short hikes with friends, along portions of the Trail that ran near DC–through Virginia, West Virginia, and Maryland.

My great love for the AT must come, in part, from how it feels to stride along, deep in the forest and far from cities.  My ego self recedes, freeing my spirit to merge with the natural world around me.  And when a thru-hiker–one of those individuals who is hiking the entire Trail–approaches, loaded down and grimy-looking, I feel I am in the presence of a rock star.    Sometimes I ask questions about what the hike has been like so far;  other times I’m too shy for more than pleasantries.  But as I continue on, I pretend that I too am hiking the whole Trail.  Even though it is unlikely that I ever will.

I am grateful to the many people who brought the Trail into existence and to those who and tend to its ongoing care.  ’A super trail along the mountain crests of the eastern wilderness’ was the dream of forester Benton MacKaye in 1921.  And by 1937, the Trail had been completed, all through the efforts of private citizens!

Today’s Appalachian Trail is different from the original version.   In 1937 the Trail went straight up and down mountain sides, making hiking difficult and erosion severe.  Over the decades, Appalachian Trail Club crews and volunteers have relocated and improved many miles of trail.  Changes and improvements are still being made.

The Trail is managed by the National Park Service, the US Forest Service, numerous state agencies, and by the non-profit Appalachian Trail Conservancy.  But most of the care and maintenance of the Trail is done by volunteer members of the more than 30 chapters of the Appalachian Trail Club, in communities along the Trail.

It was not until 1968 when Congress passed the National Trails System Act that the AT received federal protection from development.  The Act established the Appalachian Trail and the Pacific Crest Trail (a newer, 2,650 mile trail from California’s southern border to Washington’s northern border) as the nation’s first National Scenic Trails and paved the way for the establishment of more National Scenic Trails within the National Parks and National Forests system.

The majority of land through which the AT passes is forest or wild lands, although portions traverse farms, towns, and roads.  And 14 states are host to a piece of the Trail: Georgia, North Carolina, Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, New Jersey, New York, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine.  The longest stretch is in Virginia, about 550 miles of trail.

Every year, three to four million people hike some portion of the AT.  About 12,000 individuals are believed to have hiked the entire Trail.  Most of them do so in one stretch, which typically takes 5-7 months.  Others, called section hikers, complete the Trail, section by section, perhaps over a course of years, according to the time hikers have available.

I know the Appalachian Trail is cherished by many.  I gather, from what I have read and heard, that hiking the entire Trail can be life-changing, that it can help in healing after a major life loss, that it can be an inspiring and confidence-building way to move from one phase of life to another.

With gratitude, I look forward to my next day hike on the Appalachian Trail, probably a summer hike in the Shenandoah National Park.–April Moore

ap map






Flamingos Are Returning to Florida!

Tuesday, March 27th, 2018

flock of flamingos


It make me so happy that flamingos are returning to my beloved Florida!

During the decade that I lived there, 1964-1974, I never saw a single flamingo in the wild.  While the image of the giant pink wading bird was everywhere–motel signs, beach towels, T-shirts, and post cards–no real flamingos could be seen anywhere in nature.  In fact, during those growing up years in Florida, I don’t think I even thought of flamingos as actual animals who had once lived in Florida, in large colonies.  To me, and probably most other Floridians, flamingos were little more than a kitschy symbol of the Sunshine State.

So a few weeks ago, when I happened to hear on National Public Radio that  flamingos are returning to their native Everglades and other south Florida locations where they once thrived, I could have wept for joy.  I had to learn more.

You see, when it comes to the well-being of other species with whom we humans share the planet, I am always ready to believe the worst.  I am sickened, but never surprised, to learn that yet another species is struggling because of us humans.  So when I hear good news, of a species making a comeback, I am thrilled to have my habitual negativity challenged.

Wild flamingos disappeared from Florida well over a century ago.  They were a victim of the fashion industry, a casualty of the demand for large colorful feathers to adorn women’s hats.  By 1902 Florida’s wild flamingos had been hunted so relentlessly that all the wild flocks were gone.

But over the last 40 years or so, flamingos have been spotted in south Florida with increasing frequency and in growing numbers.  Until very recently, however, scientists did not know whether these flamingos were wild birds returning to recolonize their native habitat, or whether they were escapees from a captive flock at the Hialeah Race Track Park in south Florida.

In 2014, scientists and birders were astonished when more than 140 flamingos were sighted in a central Florida stormwater treatment area!  This 9,000 acre, manmade wetland, which filters nutrients from water flowing into the Everglades, turned out to be a haven for flamingos.

So to find out whether these flamingos were wild birds or merely escaped captives, scientists from Audubon Florida’s Everglades Science Center teamed up with scientists from the National Park Service and others.  They studied the historic record to determine the Florida locations where wild flocks had lived before 1900.  And satellite transmitters attached to some birds showed that they had come to Florida from Mexico and the Bahamas, not from the captive population at the racetrack park. Besides, the birds were showing up in such large numbers  in the Everglades,  in the Big Cypress National Park, and other south Florida wildlife refuges, that they couldn’t all have been escaped individuals from Hialeah.

So it’s now official.  According to the Audubon Society, the large numbers of flamingos being spotted in Florida are not escaped captives; they are heralds of a species in recovery!  And now that they are officially deemed ‘native,’ flamingos can benefit from greater management attention than they already receive under the federal Migratory Bird Treaty Act.

So the question is why flamingos are returning to their native Florida after more than a century.  The answer is that Florida has become more flamingo-friendly.  ”Many habitats we believe critical to the success of the species are already protected,” explains Dr. Jerry Lorenz, state director of research for Audubon Florida.  ”Everglades National Park, along with southern Florida’s complex of National Wildlife Refuges are the primary areas that supported flamingos in the past,” he says.  Lorenz calls for an ongoing state and federal partnership “to get the water right for all of Florida’s iconic wading birds.”  That will “translate into a bright future for the American Flamingo in Florida.”

I am hopeful there will be a time when, once again, Florida will be home to hundreds of thousands of flamingos, living in flocks ranging from hundreds to thousands of birds.  I can well imagine feeling just as John J. Audubon did, when he observed hundreds of flamingos in the wild in Florida 1832.  ”Ah!,” he wrote.  ”Reader, could you but know the emotions that then agitated my breast!”

And there is more good news!  Florida’s increasingly flamingo-friendly environment benefits other wading birds as well.  Wood storks, ibises, and roseate spoonbills are also increasing in number.  And wading birds, including flamingos, are growing in number all around the Caribbean–Mexico, Venezuela, the Galapagos, and Caribbean islands.

I dearly love thinking about these tall, extravagantly colored birds, foraging for food, mating, raising their young, living wild and free in Florida’s beautiful marshlands.

As I researched this article, I learned such fascinating facts about flamingos that I would like to share them:

  • The flamingo species that inhabits Florida and the Caribbean is the American Flamingo.  But there are five other flamingo species living in Africa, South America, and southwestern Asia.
  • The flamingo’s eating habits are unusual.  The bird walks slowly about in salty, shallow water, stirring up the muddy bottom. Then the bird leans its long neck down and puts its head in the water–upside down!  The bird scoops up a mouthful of water and then closes its beak.  The flamingo uses its tongue to force the water out through comb-like extensions on the beak that allow the water to escape but keeps the food inside.  amazing beak
  • Flamingos are not picky eaters.  They eat crustaceans, worms, algae, insects, organic debris, plants, and fish.
  • It is the carotenoids in the crustaceans and algae in flamingos’ diet that color the birds’ feathers pink.  Flamingos that are pale or white are malnourished.
  • Flamingos are mostly monogamous.  Once a pair has mated, they work together to build their nest out of mud, stones, sticks, even feathers.  Once the nest is complete, the female lays a single egg.  Parents take turns incubating the egg until it hatches 27-31 days later.  The flamingo chick, which has white or grey feathers, remains in the nest for its first week, and is fed dark red ‘crop milk’ by mother and father alike.  ’Crop milk’ comes from the parents’ upper digestive system and is rich in the fat and protein the chick needs.  After the  chick’s first week, the young bird joins the larger colony and is cared for by many adults, who teach flamingo life skills to the growing chick.
  • Flamingos do not migrate, but are known to fly long distances in response to changing conditions in their shallow water habitat.
  • A flamingo’s lifespan in the wild is 20-30 years.  The birds reach sexual maturity at about age 6.
  • The joint in the middle of the flamingo’s long legs may seem to us comparable to human knees.  But, in fact, a flamingo’s ‘knee’ is much higher on the leg, hidden by the body’s feathers.  The joint that we think of as a knee is actually equivalent to an ankle!  This means the lower half of a flamingo leg is actually a long foot, with the webbing at the bottom equivalent to toes.  Please see the photo below.–April Moore

flamingo chick



Night-Night Birdie

Thursday, March 1st, 2018


     Where do the birds go at night?  Late on winter afternoons, when all the juncoes, chickadees, and titmice I’ve watched flitting about during the day are nowhere to be seen, I wonder where they’ve gone.

I remind myself of Holden Caulfield, the teen-aged narrator of the 1950s classic novel CATCHER IN THE RYE.  Holden worried mightily about the ducks who disappeared from the pond in New York’s Central Park when winter set in.  Where did they go?

Although a worry wart by nature, I don’t exactly worry about our local birds during winter nights.  I am confident that, even if I don’t know what the birds are doing at night, they do.  Despite my late afternoon wonderings, the birds generally show up the next day.

But I am curious.  So I did a little investigating to find out what our avian neighbors do on winter nights.  It turns out, no surprise, that birds who spend the winter here have a number of strategies for staying warm on cold nights.

Many birds roost for the night in the cavities of trees.  One such bird, our perennial neighbor the chickadee, finds–or excavates– a roosting cavity in a dead tree.   And unlike nuthatches and titmice, who crowd into a tree cavity with their fellows, chickadees invariably spend their nights alone, even when temperatures plunge.  I got a thrill one morning when I walked up the hill below our house and suddenly noticed right in front of me a chickadee popping out from a hole in a small dead tree.

And woodpeckers, who made many of those tree cavities in the first place, can always excavate a new one if they don’t find an existing cavity that suits them.  Wrens also roost for the night in tree cavities. Or they may spend the night in a tangle of vines, in a stump, or even in some human creation like a planter or a  garage.

Other bird species will never enter a tree cavity, no matter how low the temperature.  But many of them do spend their nights in trees.   Goldfinches and cardinals, for example, burrow deep into conifers, gathering with their fellows, to seek protection from wind and predators.  A stand of evergreens is more popular with these birds than a single conifer in the open.  The density of multiple conifers offers greater protection.

Many birds roost for the night on a high branch, up against the trunk, which holds more of the day’s warmth than do the branches.  And roosting up next to the trunk makes it easier for a bird to detect the vibrations caused by a predator climbing up the trunk.

I think the most dramatic tree roosting habits are those of crows.  While we see and hear many crows where we live, I only occasionally see them late in the day.  However, I do remember seeing them in other places, late on a winter day, swooping in noisily from all directions into a single tree or into two or more neighboring trees.   With a great deal of commotion, hundreds of crows flutter among the branches, settling in for the night.

And some birds do not spend their winter nights in trees at all, but roost closer to the ground.  Cardinals, finches, and blue jays retire on winter nights to dense thickets of vegetation.  Tangles of briars, grape vines, and brambles seem to be enough to make them feel protected.

Juncoes also roost near the ground, in shrubs and other low plants.  I read that they like steep hillsides.  Why this would be true I don’t know, but my own observation suggests it may be true.  Early and late on winter days I often notice juncoes flitting about the steep hillside by our house, in and around the forsythia or a euonymous bush and among dry leaves and weeds.   Juncoes may also roost in open buildings and sheds in stormy weather.

Clearly, the birds I see all winter where I live are well-adapted to cold nights.  I am always happy to learn more about the habits and strategies of these gorgeous creatures I love and admire so much.–April Moore



How Pain Can Be Turned to Joy

Monday, February 5th, 2018
photo by Ira Shorr

photo by Ira Shorr

Just over a week ago I joined with about 150 people for a bracing plunge into the Potomac River near Washington, DC!

No, we were not insane.  At least not mostly.  We were raising money for the organization international climate leader Bill McKibben calls “the best regional climate organization in the world,’  the Chesapeake Climate Action Network (CCAN).

All of us ‘plungers’ had reached out to family and friends, asking them to support our plunge by making a donation to CCAN.   And collectively, we raised more than $125,000, enough to make a difference.

Fortifying ourselves and each other with whoops and hollers, we all charged out into the frigid river.  And it was our willingness to discomfit ourselves by plunging into the cold water that inspired our friends and family to make their own sacrifice (in financial form), in the service of a cause we all believe in. 

What a joyful day that was for me!  And a great gift to me to be able to experience such happiness, especially in relation to climate change, which is one of my greatest pains.

Grief about what we’re doing to the earth is my all-too-frequent companion.  I anguish over the fact that we are in the process of condemning our children and those who come after them to a life that is much harder than ours because the planet on which they live has become destabilized.  It breaks my heart to know that we are in the middle of a huge wave of extinctions, caused, in part, by global warming.  And then there is the deep frustration I feel because Donald Trump has made our country the only one on earth that is not part of the Paris climate accord.

All those sources of pain!  But the earth is my beloved, so I feel duty-bound to do what I can to protect this incredibly wonderful home of ours.

And here is the small miracle, the grace in this dilemma.  By acting with others to protect my beloved, the earth, I gain relief from the pain.  That’s the meaning of the joy I felt in our Polar Bear Plunge.

I have learned that I feel great when I join with others to do something about that which is causing us all so much pain.  Our shared pain is the motivator that brings us together.  And then we share the joy of being part of a team, a team that takes effective action to safeguard the planet we love.

However much of that happiness comes from making a contribution toward winning the battle for our climate, and how much comes from our camaraderie, this I know:  at least for me, joining with people to do something constructive changes the whole experience of confronting what is so painful for me to see.

And this emotional alchemy–turning pain into joy–can be a gift for many who, in these days, are feeling pain at what they see happening now in America, with Donald Trump as President.

These are indeed difficult times, when so much on which our climate, and also our democracy, depend is getting battered and may even be up for grabs.  So I  encourage anyone who is feeling that kind of pain to use it to become a force for good.  Joining with others in effective action will not only move the world in a good direction, but it will also lift your spirits.–April Moore

I would like to acknowledge my husband Andy Sschmookler, for contributing valuable insights that helped shape this piece.



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