Tuesday, March 31, 2009

Green Rising

By late February, the soil is beginning to thaw across the Heartland. Triggering metabolic activity in the roots of plants, the thaw advances slowly over the coming weeks. Lawns begin to green up by early March, followed by low deciduous shrubs and small trees as the month progresses. Since it takes awhile for this metabolic renewal to spread through plants, most larger trees do not begin to leaf out until April, with some species well ahead of others. Locusts and black walnuts are among the last trees to produce new shoots and leaves.

This progressive change in our landscape is absolutely vital to almost all species of life on earth; only deep marine organisms, able to feed on sulfides from hot smokers and volcanic vents, are independent of the solar food chain. The greening of plants, a reflection of chlorophyll production, initiates photosynthesis, whereby plants convert solar energy to starch and sugars. By doing so, they nourish their own growth and provide food for a vast array of herbivorous and omnivorous animals, from insects to elephants; in turn, these creatures are prey for carnivorous plants and animals and, eventually, all groups provide sustenance for bacteria, fungi and scavengers. Green is the color of life on Earth.

Monday, March 30, 2009

Crossing the Floodplain

Yesterday morning, I decided to rescue my wife's VW Beetle from its prolonged dormancy and take a country drive. Southwest of Columbia, I descended through the hills that border the Missouri River Valley and dropped onto the broad floodplain. After crossing Perche Creek, swollen and muddy from recent heavy rains, I entered the flat landscape of the valley floor.

Henbit, a ground hugging plant of the mint family, produced a brilliant, purple haze across the fields. Native to Africa and Eurasia, henbit is common throughout the eastern U.S., where its bloom, in March and April, is a welcome sign of early spring. Shallow pools dotted most of the fields, attracting small flocks of blue-winged teal, noisy killdeer and a few groups of shorebirds, too distant to identify. Horned larks foraged along the roadway, grackles and red-wings scoured the crop stubble and a lone red-tailed hawk circled overhead. Curving northward, the road climbed into the uplands, where sheep and cattle grazed the greening hillsides, mockingbirds flashed among the trees and turkey vultures soared in the clear, blue sky.

I suppose I could have stayed home to watch political pundits argue the fate of our economy or, perhaps, attend a church service to get a fiery dose of fear. But I prefer an escape to nature, the source of my peace and inspiration.

Sunday, March 29, 2009

Family Health

We are all aware that certain medical problems tend to run in families. Some of these are due to inherited factors and, short of genetic engineering, cannot be prevented. However, in many, if not most, cases, this familial clustering of disease is due to lifestyle traits that are learned by the children and, in turn, passed on to their offspring.

These familial behaviors include poor dietary habits, inactivity, smoking, excessive alcohol consumption, overuse of medications and illicit drug use. Children come to learn that these lifestyle choices are acceptable, if not the norm, and develop a similar pattern of behavior. Obese, inactive adults beget overweight children, adult smokers tolerate tobacco use by their offspring and parents that use medications, drugs and alcohol to deal with every problem encourage their children to do the same. Combined, these familial disorders and their medical complications account for a high percentage of overall morbidity, early mortality and health care costs.

Beyond their personal health issues, families that tolerate overindulgence and inactivity are also less likely to be supportive of conservation programs. This impairs our effort to reduce society's impact on the environment and, in the end, the health of our extended human family is placed in jeopardy as well.

Saturday, March 28, 2009

Historic Weather

Every year or two, Americans face "historic" weather events; the Yellowstone fires, Hurricane Katrina and the Great Flood of 1993 come to mind. So far this year, we have witnessed a severe, prolonged drought in south Texas and record flooding along the Red River near Fargo, North Dakota.

But the term "historic" is a bit misleading. North American weather records are, at most, a few hundred years old while the current ecosystems of our Continent have been developing for thousands, if not millions, of years. The landscape and vegetation patterns that we see today are a reflection of natural forces acting on the underlying geology; these forces include recurrent floods, droughts, storms, wildfires and freeze-thaw cycles.

Unfortunately, as modern man colonized America, he paid little attention to the clues of past natural events. Building our settlements on floodplains, barrier islands and moisture-starved landscapes, we have relied on dams, levees, aqueducts and deep wells to protect and sustain our towns and cities. But, as we learn time and again, we are no match for nature's whim and fury.

Friday, March 27, 2009

Season of Hope

Long before we understood the cause for our seasons, man was surely enamored with spring. After all, he was dependent upon natural ecosystems for his daily survival; the return of the sun, the opening of rivers, the greening of the landscape, the arrival of waterfowl and the explosion of game populations must have given him hope and comfort.

Today, sustained by a global economy, modern transportation and well-stocked groceries, man welcomes spring for reasons less vital to his body than to his mind. We may know the science of spring and anticipate its arrival but, until we see, feel and smell its presence, there is impatience, doubt and a hint of fear in our souls. Subconsciously, we remember our tropical home and retain the knowledge that darkness and cold threaten our survival.

Spring is more than a time of birth, regrowth and renewal. It is our season of hope.

Thursday, March 26, 2009

Nature Walk

My daily walk to work is less than a mile in each direction. Most of the route winds through our neighborhood, with its large trees and manicured lawns, while a shorter stretch passes dorms, parking lots and Greek row; crossing Providence Road, a major artery through Columbia, is the only section that requires my full attention.

This routine provides a reasonable dose of exercise but is more vital to my mental health. Often the only outdoor activity in the course of my day, the walk recharges my soul, giving me the chance to take in the sounds, sights and fragrance of the seasons. And though little open space is found along the way, the treks occur in early morning and early evening, increasing my encounters with residential wildlife; deer, raccoons, opossums, squirrels, cottontails, bats and, of course, a wide variety of birds inhabit the area.

Those who live in rural areas may scoff at this seemingly desperate attempt to find nature in an urban setting. But naturalists know that there is much to experience and understand in even the smallest outdoor environments. Besides, on my short walks I can feel the same sun that shines on the Amazon, gaze at the same moon that hovers above the Carolina shore or inhale the cold, fresh air that, just yesterday, swept across the prairies of Canada.

Wednesday, March 25, 2009

Pleistocene Rivers

During the Pleistocene, which began 2 million years ago, continental glaciers plowed into the Northeast and Upper Midwest; four glacial advances were separated by warm, interglacial periods, during which the ice sheets melted back into Canada. In fact, many climatologists believe that the Holocene, in which we live, is just another inter-glacial hiatus and that the ice will return within 5-10 thousand years.

Looking at a topographic map of North America, one can easily observe the flattened landscape that represents glaciated terrain. Stretching through western New York, western Ohio, the northern two-thirds of Indiana, Michigan, most of Illinois, northern Missouri, Iowa, Wisconsin, Minnesota and the eastern Dakotas, this province was plowed flat as the glaciers advanced and was coated with till as the ice sheets retreated. The Missouri River outlines the southern limit of glaciation to the west while the Ohio formed when the Teays River, which drained a broad swath from Virginia to northern Illinois, was blocked by ice.

Having scooped out the Great Lake basins as it plowed southward, the last Pleistocene glacier, the Wisconsin, filled them with meltwater as it retreated, some 12,000 years ago. With northern outlets still blocked by ice, the lakes spilled southward, forming and/or widening the river channels that we find today: the Susquehanna, the Great Miami, the Kankakee, the Wabash, the Illinois, the Upper Mississippi, the Minnesota and many smaller streams. Once the last glacier melted into northern Canada, the Red River and St. Lawrence River opened outlets to Hudson Bay and the Atlantic, respectively, and, combined with an upward rebound of the land, produced the drainage pattern that we find today. Current river and stream maps should be good until future glaciation, asteroid impacts or continental collisions readjust the terrain.

Monday, March 23, 2009

Spring Storm

After dropping from the Gulf of Alaska and cutting across the Intermountain West, a potent spring storm is poised to move onto the Plains. Now centered over northeast Colorado, this storm, energized by the jet stream, is wrapped by strong, counterclockwise winds; ahead of the system, warm, moist air is streaming up from the Gulf of Mexico while, to its north, blizzard conditions are developing across the Northern Plains.

Here in Missouri, the leading edge of the warm air has ignited a line of showers and thunderstorms; rather tame, they are moving off to the northeast and strong, southerly winds will follow as the cold front approaches from the west. Primed with warm, humid air, our region can expect more potent storms and heavy rains tonight and tomorrow. Fortunately, since the system is moving north of our State, we should not receive any significant snowfall or severe cold this time around.

Such Pacific storms are common through the spring, providing vital rains that nourish the varied ecosystems of America's Heartland. Of course, they also bring floods, tornadoes and blizzards.

Sunday, March 22, 2009

Color Returns

After months of a drab, winter landscape, pockets of color have appeared across central Missouri. The red maples, in bloom for two weeks, are now joined by flowering magnolias and plums. Bright, yellow forsythias dot the fence rows and swaths of daffodils, hyacinths and early tulips adorn the yards.

The greening lawns, now speckled with violets and dandelions, attract cottontails, robins and grackles while borders of honeysuckle, lilac and azalea are taking on the verdant look of spring. With heavy rain forecast over the next few days, this transition to fragrance and color will intensify and winter's grip will fade. Within a few weeks, the roar of lawnmowers will echo across our suburbs, insects will reclaim the land and the birds of summer will return from the south. Long live spring!

Saturday, March 21, 2009

Cancer, Survival and Luck

The diagnosis of cancer is certainly one of the most dreaded of human experiences and we all admire the courage of those who must face this malady. Unfortunately, the focus on cancer survivors, a fund-raising and marketing tool for a number of companies and organizations, can be misleading.

Cancer encompasses a wide spectrum of diseases, some of which are far more responsive to current therapies than are others; even specific types of cancer vary widely in their prognosis, depending upon their stage, their aggressiveness and their susceptibility to surgery, drugs and radiation. Furthermore, access to certain treatments may be affected by a number of variables, including financial, social and medical factors.

Cancer survivors are fortunate to have had responsive tumors and the means to treat them. We must not imply that individuals who fail to recover are less courageous, less motivated or somehow less deserving of a cure. Despite our efforts toward the prevention and early diagnosis of cancer, luck continues to play a significant role in its treatment; hopefully, ongoing research and a commitment to universal health care will eventually eliminate this variable and all cancer victims will become survivors.

Friday, March 20, 2009

The Astronomical Spring

As I write this blog, the spring equinox is occurring across the Northern Hemisphere, the half way point between the winter solstice and summer solstice; the latter two events occur when, due to the tilt of the Earth's axis, our Hemisphere leans most away from or most toward the sun, respectively. By definition, spring stretches from the spring equinox to the summer solstice, making this the first day of that beloved season.

Falling on or about March 21, the spring equinox provides no guarantee that winter is over in our Hemisphere. While periods of warm weather usually precede the equinox, periods of cold weather are just as likely to follow it; indeed, the last freeze across most of North America's Temperate Zone generally occurs well into April.

But, after a long winter, it's always reassuring to know that we're now on the warmer side of nature's cycle and that the days will continue to lengthen for the next three months. We are, after all, tropical creatures.

Wednesday, March 18, 2009

The Pope, Sex and Suffering

Pope Benedict, the anointed leader of the Catholic Church, is visiting Africa this week. Among his declarations upon arriving in that land of famine, genocide and political corruption: condoms should not be used to prevent HIV transmission. "Just say no," is the papal solution to the scourge of AIDS.

Governed by an army of "celibate" priests, bishops and nuns, the Church has always been squeamish about human sexuality. And its stance against birth control has contributed to a vast array of human suffering: hunger, abused children, unsafe abortions, venereal disease and childhood AIDS, to name a few.

But then the Catholic Church has always been enamored with suffering, the express route to eternal bliss.

Tuesday, March 17, 2009

Spring Vigil

It's that time of year when Midwesterners, enticed outdoors by mild, bright evenings, scour their yards for signs of spring. I am one of those who take part in this annual vigil.

Last evening, with the temperature at 64 F, I discovered many hopeful signs. The lilacs, honeysuckle, elderberries and wild cherries are all beginning to leaf out and the latter plants, transplanted from our Colorado farm, have blossoms for the first time. The magnolias are about to pop, the crocuses are reaching their peak, the grass is greening and, as discussed yesterday, clumps of wild green onion adorn the lawn.

The chorus of birdsong, past the robin-cardinal stage, is now more varied and intense, with the homesick tune of white-throated sparrows ringing through the neighborhood. Within another week, the tide of spring will bring fragrance and color back to the landscape, as violets, dandelions, daffodils, magnolias and hyacinths make their appearance. Winter may throw a few more jabs but spring has won the battle.

Monday, March 16, 2009

Lawn Onions

Among the most reliable signs of early spring are the clumps of wild green onion that appear across our lawns. Members of the lily family, they are in the Allium genus, which includes chives, leeks, garlics, shallots and onions; numerous subspecies of wild onion are found throughout the Northern Hemisphere.

Sprouting in late February or March, the long-leafed clumps will, if uncut, eventually support a tall flower stalk; depending upon the species, this stalk yields papery white-pink flowers or a cluster of tiny bulbs. As the summer heat builds, the lawn onions die back until their leaf clumps reappear in September. Over time, this prolific plant can take over much of a suburbanite's precious turf, triggering a long war to control this perennial. For those of us who refuse to spread herbicides across our property, keeping the plants cut back before flowering is probably the best solution.

On the positive side, once cleaned, all portions of the wild green onion are edible and have long been used by native human cultures. The bulbs of this plant, resembling those of day lilies, are much smaller than those of cultivated onions but their pungent odor attests to their close family ties.

Sunday, March 15, 2009

Living in the Present

Wild creatures live exclusively in the present. They do not anticipate the future nor dwell on the past. Since their lives are governed by instinct and learned behavior, they have no worries and no regrets.

Humans, on the other hand, are often consumed by their past and their future. Young persons can't wait to be older and the elderly mourn the loss of their youth. Those of us in the middle mull over past decisions and worry about future challenges; the past usually seems better than it was and the prospect of aging and dependence weigh heavy on our minds.

In my experience, it is our inability to live in the present that usually leads to unhappiness. The grass was and might be greener. But, while it's good to learn from past mistakes and to plan for the future, the past cannot be changed and the future may end tomorrow. It is best to enjoy your health, your passions, your family and your friends while you can. A commitment to live in the present is a gift to yourself.

Saturday, March 14, 2009

Red Maples

Despite a coolish start to March, the red maples have been blooming in Columbia this week. Native to eastern North America, these trees, often called swamp maples, prefer moist, lowland soils and are often found in the company of sycamores, river birch, boxelder, silver maple, green ash and cottonwoods. Due to their early spring flowers, fast growth and scarlet fall foliage, red maples are also widely planted as ornamentals.

The red male and female flowers, which appear along the bare terminal stems, occur on the same tree; by late spring, the paired, winged seeds develop. Adult trees may grow to 80 feet and their soft wood (they are also called soft maples) has long been used for furniture, gun stocks, tools, flooring and firewood. But it is their early flowering that makes these trees most valuable to many humans, offering a sign that spring is about to take control.

Friday, March 13, 2009


Mention "desert" and most Americans will likely think of saguaros. These tall, branched cacti are an indicator species of the Sonoran Desert, which extends across southern Arizona, through a sliver of southeastern California and into northwestern Mexico.

Favoring elevations between 2000 and 3500 feet, the saguaro is one of the slowest growing and longest lived plants in North America; reaching a height of 3 feet in its first 30 years, the main trunk begins to branch by age 65 and a healthy adult plant may live to be 200 years old. Its thick frame is supported by woody ribs while its pulp, coated with a thick, waxy skin and rows of 2-inch needles, expands and contracts with the seasons. Despite its meager, shallow root system, this cactus absorbs massive amounts of water during the monsoons of summer and is able to tolerate prolonged periods of drought. Some saguaros mature with a distorted, fan like (montrose) growth pattern; this may represent a genetic variant or result from an acquired condition (frost or insect damage).

Clusters of tubular, white flowers develop at the tips of the trunk and branches in May and June; opening at night, they are pollinated by bats, doves and a number of insects. The red fruits of the saguaro, pulpy and sweet, are consumed by a wide variety of wildlife and were a staple food source for Native Americans. The abundant seeds are spread across the desert via bird and animal droppings where a small minority, protected beneath shrubs, will germinate and begin their slow, steady growth. As adult plants, the large cacti may fall victim to winds storms and may become home to a host of creatures; gila woodpeckers and gilded flickers open nest cavities in many of the saguaros, later used by elf owls, ferruginous pygmy owls and a variety of small mammals.

Thursday, March 12, 2009

Earth's Largest Wilderness

Though continually threatened by human population growth, there are still many vast wilderness areas across this planet, including tropical rain forests, deserts, grasslands, boreal forests and polar habitats. But the largest and least explored of these ecosystems is the deep, dark ocean.

Oceans cover 70% of Earth's surface and have an average depth of 12,000 feet. Sunlight only penetrates to a depth of 450 feet, leaving an extensive realm of dark, marine habitat, of which little is known. Unlike space exploration, which has benefited from a significant amount of federal funding, the study of our deep oceans has been left primarily to privately financed groups. This is counter intuitive, considering our close, personal relationship with the sea and the various ways in which the deep ocean environment affects our climate, our atmosphere and our food chain (to name just a few critical items).

The exploration of our largest wilderness will likely lead to many unexpected discoveries, give us further insight into the ongoing evolution of our planet and provide a vital barometer of human impact on the health of our oceans. After all, they were the cradle of life on Earth and their welfare is closely linked to our own.

Wednesday, March 11, 2009

Winter Rewind

The change to daylight savings time, combined with a new Arctic blast, made it feel like January as I walked to work this morning. Darkness, lit only by a brilliant full moon in the western sky, and a temperature near 20F were in sharp contrast to the mild, sunny mornings of last week.

This return to winter will last a few days as a broad trough encompasses much of the eastern U.S. Near record lows are developing across the Upper Midwest and daily highs have dropped more than 30 degrees through much of the South. On the positive side, this low dip in the jet stream is forecast to bring significant rainfall to Texas, which has endured a prolonged drought.

Winter's temporary victory should yield to spring by this weekend and our faith in nature's cycle will be restored. Patience, not a common human trait, is often tested in March.

Tuesday, March 10, 2009

The Nature of Morality

As the subject of stem cell research re-enters the public discourse and the residue of corporate greed penetrates our daily existence, an attempt to define morality and its place in human life seems to be appropriate. In doing so, one must first consider whether humans are naturally equipped with a moral compass or whether it is instilled by others.

Man has long debated whether or not humans are endowed with inherent goodness. This debate is generally intertwined with spiritual and religious philosophies, leading many to conclude that one must be religious to be moral. In fact, history argues against this point of view; the Holocaust and Inquisition were conducted by religious zealots and most modern terrorist groups espouse fundamental religious convictions.

Morality, in my opinion, is the impulse to do what is right, a trait that promotes the common good. While humans may be born with moral tendencies, they must be nurtured to endure. The tenets of morality are principles, not beliefs, and they cannot be imposed or legislated. To be a moral person is to shun selfishness, greed and intolerance; to do so, one must continually resist the political, social and religious forces that strive to divide us.

Monday, March 9, 2009

A Supercharged Low

Two low pressure zones have merged over the Central Plains, attached to a steep dip in the jet stream. This potent low, energized by the jet, is pulling up warm, humid air from the Gulf of Mexico, priming the Midwest for a violent clash of air masses.

Behind the advancing front, Arctic air will spill into the northern Plains and Upper Midwest, producing a marked contrast with the summer like soup ahead of the storm. Like a giant mixer, the central low will provide "lift," sweeping spring above winter (to its north) and winter below spring (to its south). Near its course, west and southeast winds will collide, triggering rotation in some of the thunderstorms as they slide northeastward ahead of the front.

Such conditions are expected to develop from Arkansas to Ohio by tomorrow, producing heavy rain, severe thunderstorms and tornadoes along and ahead of the front; northwest of the storm, across the Upper Midwest and Great Lakes region, a blizzard of heavy snow and high winds is forecast. Nature's battlegrounds are often violent and seldom boring.

Sunday, March 8, 2009

Stormy Day at Swan Lake

Despite dire warnings from the Weather Channel, I was determined to visit the Swan Lake National Wildlife Refuge, in north-central Missouri, as planned. The first squall line hit just east of Brunswick and several more followed over the next two hours; but between these torrential downpours, warm, sunny conditions enticed numerous birds and mammals onto the flooded fields and marsh-lands. Finally, by mid morning, the front had pushed through and cool, cloudy weather prevailed.

Established in 1937 to protect habitat for wintering and migrant waterfowl, the Refuge is a mosaic of cropfields, lakes, wetlands and riparian woodlands. Today's residents included large flocks of snow geese, smaller (but no less noisy) flocks of Canada geese and a wide variety of ducks. At least 100 American white pelicans settled on Swan Lake during my visit and I saw eight bald eagles through the morning. Other common birds included meadowlarks, red-winged blackbirds, killdeer, American kestrels, ring-billed gulls, red-headed woodpeckers and horned larks. Mammals were also stirred by the heavy rains, including small herds of white tailed deer that splashed across the fields and a handful of coyotes. An unexpected finding was a flock of tree swallows, cruising above a roadside slough; this is the earliest that I have ever seen this species in Missouri, no doubt a reflection of our recent strong, southerly winds.

Swan Lake NWR is just northwest of Mendon, Missouri, with access off routes CC (from the east) and 114 (from the north); route RA, south of Sumner, is the most direct route to the Visitor Center. As is evident from the above narrative, March is an excellent time to visit the refuge.

Saturday, March 7, 2009

The Orphaned Planet

Discovered in 1930, Pluto was classified as the ninth and most distant planet in our solar system until the discovery of Eris, in 2006. The latter planetoid, actually larger than Pluto and also possessing a moon (Pluto has three), triggered a major controversy in astro-nomical circles, leading to the reclassification of Pluto as just another large object in the Kuiper Belt; this Belt is a broad swath of asteroids that circle the sun beyond the orbit of Neptune.

Smaller than our moon, Pluto orbits the sun every 248 years; its elliptical orbit, with a radius ranging from 2 to 3.4 billion miles, actually takes Pluto closer to the sun than Neptune during part of its orbit. Furthermore, during its "closer" approach, Pluto develops a thin atmosphere as some of the frozen methane, nitrogen and carbon dioxide on its surface is vaporized.

Regardless of its scientific classification, Pluto will remain a distant, dark world of rock and ice. Humans, fueled by theoretical arguments and emotional sentiment, will likely continue the debate, hoping to reclaim this orphan as one of our own. But humans are like that.

Friday, March 6, 2009

Glacial Lakes

The great majority of natural lakes on our planet are found in glaciated regions. And, since lakes are among the more transient features of our landscape, most of these formed during the last glacial period of the Pleistocene (the Wisconsin Glaciation), which stretched from 70,000 to 10,000 years ago.

Glaciers produce lakes in three ways: scooping out lake basins, damming streams or calving ice chunks as they retreat. The Great Lakes of North America and the Finger Lakes of New York State are examples of the first mechanism; they occupy basins or deep gorges that were carved from the bedrock by advancing ice sheets. In alpine areas, mountain glaciers have produced smaller lakes in a similar fashion; these now occupy cirques and basins within glacial valleys.

Glacial deposits and the ice sheets themselves often blocked major streams and rivers, producing broad, shallow lakes; the classic example is Lake Agassiz, which formed when the Red River was dammed by a lobe of the Glacier. At its peak, this lake was four times the area of Lake Superior, covering much of south-central Canada and the adjacent parts of North Dakota and Minnesota; the dam melted away 8000 years ago and much of Lake Agassiz drained into Hudson Bay, leaving Lake of the Woods and Lake Winnipeg as remnants.

Finally, numerous kettle lakes dot the vast glaciated plain of Canada, New England and the Upper Midwest. Described more thoroughly in an earlier blog, these lakes formed as chunks of ice broke from beneath retreating ice sheets; embedded in the glacial till, they melted as the climate warmed, leaving depressions that refilled as drainage patterns developed. When viewed from the air, these kettles are aligned in sweeping curves, documenting the path of glacial retreat.

Thursday, March 5, 2009

Frog Season

In the Midwest, frog season begins by early March and lasts into the fall. Spring peepers and chorus frogs are the first to emerge, often calling from icy waters as winter and spring dance through the month. By the end of March, they are joined by leopard and cricket frogs; the trills of American toads mellow the chorus by mid April but, ironically, the larger green and bullfrogs are often quiet until May.

Regardless of the species, frogs tend to favor seasonal ponds and shallow wetlands, where their abundant eggs will not be consumed by fish. After the breeding season, they lounge about, feasting on the numerous insects and other invertebrates that inhabit our swamps and marshlands; bullfrogs are known to consume a wide variety creatures, including small birds and mice. The frogs and their tadpoles are, in turn, the quarry of snakes, snapping turtles, raccoons, mink, wading birds and humans.

By mid autumn, most of these amphibians have settled into their winter retreats, buried in mud or leaf litter. But it is in late winter, when the calls of the early tree frogs echo across our wetlands, that we most appreciate these water-loving neighbors. Theirs is the voice of spring.

Wednesday, March 4, 2009

Water Gaps

As humans spread across the globe, we often encountered rivers that had cut canyons directly through a mountain ridge. Prior to our understanding of geologic processes and plate tectonics, these gorges were attributed to the power of the river which, apparently, had drilled its way directly through the mountain; in some cases, this assumption was conflicted by the fact that the stream could have easily flowed around the edge of the ridge.

Today, we know that these "water gaps" developed as the river (or its predecessor), entrenched in deposits above the ridge, sliced through the mountain as the river cut downward and/or the ridge was uplifted. This phenomenon is especially widespread across the Ridge & Valley Province of the eastern U.S.; prime examples include the Delaware Water Gap (on the border of Pennsylvania and New Jersey) and the Potomac Water Gap at Harper's Ferry, West Virginia. Out west, Split Mountain, in Dinosaur National Monument, was bisected by the Green River as it rose and the river cut downward; initially encased in Tertiary sediments, the Carboniferous rock is now a free-standing ridge, split by the stream.

Once again, our interpretation of the landscape, like our assumptions about the Universe, are based on our current knowledge and perspective. What was accepted as fact yesterday may prove to be folly tomorrow. Understanding water gaps required the closure of our own knowledge gap.

Monday, March 2, 2009

Coastal Snowstorm

A broad dip in the jet stream has allowed cold, Canadian air to drop across the eastern U.S. over the past few days. In concert, a center of low pressure, riding the southern edge of this trough, has brought snow to the lower Mississippi Valley, the Gulf Coast region and the Southeast. Last evening, the storm turned to the northeast and will move up the coast, from Virginia to Maine.

Sweeping Atlantic moisture over the entrenched cold air, this late winter storm is forecast to produce heavy snow across the urban corridor, impacting over 40 million Americans and delaying many more who travel through the region. Though March is usually lumped with the "spring months," such snowstorms are not unusual during this month as an erratic jet stream triggers a clash between warm and cold air masses.

Fortunately, the frigid air and heavy, wet snows don't last long. A higher sun, longer days and a rapid rebound in temperatures quickly convert the beautiful white blanket to slush, mud and swollen streams. Such is the nature of March.

Sunday, March 1, 2009

March toward Spring

March is a well named month. It is, after all, a journey from winter to spring and, in contrast to a pleasant stroll, it can be a rugged, sloppy trip. There will be wet snows, cold rains and icy winds. We will cross muddy fields, swollen streams and slippery hillsides.

It is, indeed, the most fickle of Midwestern months, encompassing the peak of the winter-spring battle. But, for the naturalist, March has plenty to offer. Waterfowl migrations surge through the month, lovesick mammals wander the landscape, wetlands come alive with the call of tree frogs, wildflowers spread through the woodlands and, by the end of the month, the first summer birds begin to arrive.

And, of course, our journey will bring us to those mild, fragrant days of April, when winter has lost its grip and renewal begins in earnest. Until then, we'll slog our way through March.