Friday, September 30, 2011

A Change of Latitude

After almost two weeks in the cool, scenic landscape of northern Michigan, we are back in central Missouri. It is warmer here and the autumn colors are just beginning to unfold but the terrain is hardly spectacular.

Nevertheless, it is a glorious, sunny day in the Heartland and I opted for a visit to the Eagle Bluffs Conservation Area, southwest of town; stretching along the Missouri River floodplain, it is an excellent birding area during any season and offers a pleasant mix of wetlands, fields and riparian woods, backed by the forested bluffs of the river valley. Today, hundreds of turkey vultures dominated the scene, gathering on levees to await the mid morning thermals; killdeer were also abundant and there was the usual cast of great blue herons, blue-winged teal, red-winged blackbirds, bald eagles, northern harriers and migrant shorebirds. A special treat was provided by a trio of sandhill cranes that circled across the refuge.

Following vacations to areas with magnificent scenery, many of us are dismayed to return to our familiar and seemingly mundane surroundings. But, as naturalists know, every region of this planet offers a tremendous diversity of native plants and animals; unfortunately, most people never bother to explore that natural bounty. Today's visit to Eagle Bluffs reminded me that the opportunity to enjoy the wonders of nature is always close to home.

Wednesday, September 28, 2011

Elk in Michigan

North American wapiti, more commonly known as elk, are generally associated with mountainous regions of the West. However, before white settlers arrived with their guns, axes and plows, these large herbivores inhabited much of the Continent. Nevertheless, I was surprised to see "Elk Crossing" signs in the northern part of Michigan's Lower Peninsula during our recent visit and have since learned that this is the largest free roaming elk herd east of the Mississippi.

Elk were extirpated from Michigan by the late 1800s due to a combination of over-hunting and habitat loss. Then, during the second decade of the 20th Century, efforts were made to re-establish an elk population in the Pigeon River watershed of the northeast Lower Peninsula; despite some initial success, poaching and the degradation of habitat proved to be significant problems. Finally, through the cooperation of landowners, the general public and the Department of Natural Resources, the Michigan elk population began to stabilize in the 1970s and has recently been maintained between 800-900 wintering individuals; habitat restoration and a strictly controlled hunting program have been instrumental in this effort.

While the reintroduction of a native species is, in general, a laudable project, it cannot be successful without both adequate habitat protection and a reliable means of population control. Since the State has no plans to reintroduce gray wolves and cougars in this region, population control falls to human hunters. Indeed, one wonders whether hunting and tourism proponents were the driving force behind this elk reintroduction program. The public surely enjoys the opportunity to observe these magnificent animals in the wild but, for all practical purposes, the State of Michigan has created a regional hunting preserve.

Tuesday, September 27, 2011

Falling Water

As we left the cabin this morning, on our final day in Michigan's Upper Peninsula, a light rain was falling. The Porcupine Mountains were shrouded in fog as we headed west on the Park's South Boundary Road. We stopped to take a short loop hike in the morning mist, trudging along muddy paths and weaving through the soggy vegetation; two small but scenic waterfalls, Overlooked Falls and Greenstone Falls, rewarded our perseverance.

In the westernmost section of the Park, we hiked along the magnificent Presque Isle River, stopping to view its three major waterfalls and a cluster of rock-walled potholes, scoured out by the relentless river and its cargo of abrasive sand. From there we headed further west to the Black River Valley, in the Ottawa National Forest, where a family of five bald eagles endured the chilly drizzle in the top of a dead pine; another group of spectacular cascades were spaced along this stream and a beautiful crescent beach stretched northward along Lake Superior from the Black River Harbor.

Despite the gray, damp weather, it was another enjoyable day in this land of water and rock. Heading toward Iron Mountain on Route 2, we traversed a final assault of heavy rain before the clouds pushed to our south and brilliant sunshine ignited the painted autumn forests of the Upper Peninsula. Tomorrow we'll head for Madison, Wisconsin, my wife's college hangout.

Monday, September 26, 2011

The Precambrian Peninsula

The western third of Michigan's Upper Peninsula, including the Keweenaw Peninsula, does not lie within the Michigan Basin. Rather, from a geophysical point of view, it is part of the Wisconsin Dome, which also includes much of northern Wisconsin and northeast Minnesota; in this region, which blends with the Canadian Shield, Precambrian rocks outcrop at the surface since overlying, younger sediments were either scraped away by the Pleistocene glaciers or eroded away in the distant past due to the general uplift of these ancient basement rocks.

We decided to give our legs a rest today and took a road trip to Copper Harbor, stopping at various lighthouses and beaches along the way. The highlight of the trip was the view from Brockway Mountain, just outside Copper Harbor; from this summit, one enjoys a panorama of Lake Superior and the northern Keweenaw Peninsula, including the shipping lanes, the rocky shoreline, inland lakes and colorful, forested ridges. Wherever we stopped, outcrops of Precambrian rock, volcanic or continental, dominated the scene; along portions of the coast, hogbacks and shoals of ancient basalt created a fascinating and scenic topography.

As I discussed yesterday, the Porcupine Mountains are volcanic in origin, as are some other ridges and uplifts across the Wisconsin Dome. Other ranges, such as the Huron Mountains east of Keweenaw Bay, have eroded from localized Precambrian domes (similar to the formation of the Black Hills and Adirondacks). Of course, the highlands across the Wisconsin Dome are among the oldest in North America (1-3 billion years old) and, over time, have eroded into hills and relatively low ridges. Just knowing you are walking on or amidst rock that pre-dates terrestrial life is an exhilarating experience.

Sunday, September 25, 2011

The Porcupine Mountains

About twenty miles west of the Keweenaw Peninsula, the Porcupine Mountains rise above the south shore of Lake Superior. Volcanic in origin, the "Porkies" formed 1 billion years ago along the Mid-Continent Rift; long quiescent, this rift extends southwestward into the Central Plains of the U.S. where, since buried by younger sediments, it remains a potential source for deep earthquakes.

Since their Precambrian birth, the Porcupine Mountains have been assaulted by the forces of erosion, especially during the Pleistocene Epoch when glaciers scoured the region. Today, an escarpment, capped by volcanic basalt, curves along the northern edge of the Porcupines, separated from the main uplift by the Big Carp Valley and its beautiful Lake of the Clouds; hikes along the escarpment are among the most scenic in the Park. Another popular hike is a short but steady climb to the top of Summit Mountain, 1958 feet (the highest point in the Porcupines), where a lookout tower offers a magnificent panorama of the Park and its surroundings, extending to Lake Superior; on a clear day, one can see the Apostle Islands (to the northwest) and Isle Royale, 80 miles to the north.

While the Porcupine Mountains formed 600 million years before life crawled from the sea, they now host a spectacular diversity of plant and animal residents. Among these are black bear, gray wolves, fishers and, of course, porcupines; so far, our mammal encounters have been limited to deer, squirrels, chipmunks and other humans. A Visitor Center, at the east entrance to this Michigan State Park, provides an excellent introduction to the region's natural and human history and access to this scenic refuge is provided by a well-engineered network of trails and boardwalks. Visitors should be aware that a Park passport fee is charged.

Saturday, September 24, 2011

Roughing It

We'll be roughing it for the next three nights; well, not exactly. We have rented a fully furnished cabin on the south shore of Lake Superior, just a few miles east of the Porcupine Mountains. While I am an avid naturalist and enjoy outdoor exploration during any season, I'm past the age when the proposition of sleeping in a tent and cooking over a campfire is an appealing opportunity; after a day of hiking, I enjoy a hot shower and a comfortable bed. Besides, it's difficult to watch college football in a tent!

After leaving Munising enveloped in fog and drizzle, we made a brief circuit through Marquette and then headed west across another stretch of Michigan moose country; despite the highway warning signs, we did not encounter any of those large herbivores but did see plenty of white-tailed deer. Based on a recommendation in our travel guide, we headed for an isolated point between Keweenaw and Huron Bays; though our adventure required a long drive on a graveled road on this chilly, gray, blustery day, two other couples also turned up at that scenic location during our visit, a reminder that solitude is becoming a rare gift on planet Earth.

If we manage to survive the night in our not-so-rustic cabin, we plan to head to the Porcupine Mountains for a day of hiking tomorrow. Here's hoping that the central heating system wards off that chilly breeze from Lake Superior!

Friday, September 23, 2011

Pictured Rocks

The Pictured Rocks, which tower above Lake Superior east of Munising, are likely the most photographed natural feature of the Upper Peninsula of Michigan. These scenic cliffs anchor the west end of the Pictured Rocks National Lakeshore, which extends eastward to Grand Marias. Composed of Cambrian sandstone, deposited in a broad river delta about 550 million years ago, these rocks lie in the outermost band of the Michigan Basin and are some 400 million years older than the Jurassic sediments at the Basin's center.

This morning, my wife and I took a boat tour along the base of the Pictured Rocks; conducted by a private company in cooperation with the National Park Service, the tour provided a unique and up-close view of the spectacular cliffs that were exposed by Pleistocene glaciers and are now molded by the erosive forces of Lake Superior and the region's harsh northern climate. Rock falls are a common occurrence along this majestic wall, producing recessed caves, natural arches and varied rock formations that evoke images in the eyes of human visitors (hence the name of Pictured Rocks). The boat officers and an onboard Park ranger introduced us to both the natural and the human history of this region, including the story behind many of the shipwrecks that have occurred along this storm-ridden coast.

Later in the day, we hiked out to Chapel Rock, where a pine tree grows from the top of a rock pedestal, its roots dangling between the pedestal cap and the adjacent cliff; those roots formerly ran through the soil of a rock arch before the latter collapsed into the lake. On our loop hike to and from this popular site we passed through a karst landscape which included Chapel Falls and numerous sinkholes; this topography reflects the layer of Ordovician dolomite that overlies the Permian sandstone south and east of Pictured Rocks (i.e. toward the center of the Michigan Basin). Tomorrow, we'll head westward to the Keweenaw Peninsula and thence to the Porcupine Mountains.

Thursday, September 22, 2011

South of Superior

When we arrived at Whitefish Point this morning, a raw, northwest wind raised whitecaps on Lake Superior where an ore ship, similar to the Edmund Fitzgerald, was closing in on Whitefish Bay; backed by the rugged cliffs of the Ontario coast, the freighter was headed for the locks at Sault Ste. Marie. Noisy gulls cavorted in the cold, steady breeze, a flock of horned larks scurried across the barren, pebble-strewn beach and, out on the calmer bay, a lone red-throated grebe and a trio of common loons dove for their breakfast.

Once back in our warm car, we headed west, crossing the wooded bogs of Michigan's moose country. Along the way, we took side trips to the Lower and Upper Falls of the beautiful Tahquamenon River, where its pristine waters tumble over shelves of early Paleozoic sandstone and dolomite. Further west, we returned to the southern shore of Lake Superior, entering the Pictured Rocks National Lakeshore at Grand Marias; hikes to Sable Falls, the Grand Sable Dunes and the Au Sable Lighthouse rounded out our day. After a night in Munising, we'll return to the Pictured Rocks coast tomorrow morning.

It was fitting to end our day at the Au Sable Lighthouse, which commands a spectacular view of Lake Superior. Built in 1910 and restored during the past decade, the light is both a beacon of hope amidst the harsh conditions of this northern coast and a silent memorial to the many lives lost in the turbulent waters of this magnificent lake.

Wednesday, September 21, 2011

Mackinac Island

Mackinac Island is an erosional remnant, carved from Devonian limestone by the forces of ice, wind and water. It sits in the Mackinac Strait, between Lakes Michigan and Huron, and is accessed by a twenty minute boat ride from the mainland; since no motorized vehicles are allowed on the island, all land transportation is by foot, bicycle or horse power.

Like all tourist resorts, Mackinac Island has its share of luxury hotels, brew-pubs, T-shirt shops and fudge kitchens. But most of the action and secondary tourist congestion is limited to the main downtown area and those with the energy and interest to bike or walk to other parts of the island are rewarded with broad shoreline vistas, woodland trails, peaceful lanes and a host of historic sites, including an 18th Century British Fort. Wave action and stream erosion along the coast has also produced a number of rock formations, including the famous Arch Rock.

Though it is a cloudy, damp day in northern Michigan, we enjoyed an 8.5 mile bike ride around the edge of the Island, taking in views of the Mackinac Bridge, Lake Huron and of the Island's scenic coast; among the birdlife were ring-billed and herring gulls, Canada geese, cormorants, red-breasted mergansers, a few common loons and an apparent flock of scoters, too distant to identify. Once the rain stops, we plan another journey through the center of Mackinac Island; by mid morning, we'll return to the mainland and head for the Upper Peninsula.

Tuesday, September 20, 2011

Sleeping Bear Dunes

Stretching along the northwest coast of Michigan's lower peninsula, massive sand dunes rise above Lake Michigan. Protected as a National Lakeshore since 1970, these dunes attest to both the erosive force of the Pleistocene glaciers and the powerful storms that have regularly lashed the region since those ice sheets retreated. While lakeshore "beach dunes" are modest in size, those atop the cliffs, known as "perched dunes" and composed of glacial sand, tower up to 450 feet above the waters of Lake Michigan and encompass a broad swath of shifting landscape. Bordered by a rich beech-maple forest, the dunes are temporarily stabilized by beach grasses, wildflowers, sand-tolerant shrubs and groves of cottonwood but, over time, are sculpted and advanced by the relentless wind, swallowing tracts of forest that lie in their path.

A Visitor Center, located in Empire, offers an introduction to the natural history of this fascinating ecosystem and provides an overview of the plants and animals that inhabit the dunes and adjacent forest. In addition, an auto tour road provides access to a host of overlooks, several of which yield spectacular views of the dunes, Lake Michigan and offshore islands. Those with the time and ability to do so are encouraged to hike at least one of the trails that lead into this beautiful yet harsh environment; trudging through the sand, especially when accompanied by intense sunshine and a strong wind, makes one appreciate the true nature of this unforgiving landscape.

Sleeping Bear Dunes National Lakeshore is located about 28 miles west of Traverse City, Michigan and is best reached via Michigan Highway 72. Its name is derived from a prominent dune that, topped by a clump of shrubs, resembled a sleeping bear in the eyes of Native American residents. While modern visitors might not appreciate that visual interpretation, they are sure to agree that this scenic coastline is one of the most spectacular sites in North America.

Monday, September 19, 2011

North by Northeast

It was a mild but overcast day as we drove northeast across the till plains of the American Midwest. Despite the low clouds, intermittent fog and pockets of drizzle, the golden hues of late summer adorned the landscape and brightened our journey.

We entered the Michigan Basin in northern Illinois, where the Kankakee Arch, a deeply buried ridge of ancient, Precambrian rock, divides the Michigan Basin, to its northeast, from the Illinois Basin, to its southwest. Of course, the Pleistocene ice sheets flattened this region and buried the underlying bedrock with a thick layer of glacial till; as a result, there is no surface topography that reflects the deep divide and surface streams cross freely from one geologic basin to the other.

In southwest Michigan, we traveled northward, paralleling the shore of Lake Michigan and passing inland dunes, remnants of the Lake's larger, post-glacial predecessor. Past Holland, we turned eastward to Grand Rapids and then continued northward, entering the scenic, wooded hills that cover the heart of the Michigan Basin; with every mile, the colors of autumn became more intense and the percentage of conifers, relative to their colorful, broadleaf neighbors, continued to increase. Finally, having booked a hotel room in Traverse City, we took an evening stroll along West Traverse Bay, a welcome bit of exercise after a ten hour drive. Tomorrow, we plan a morning visit to Sleeping Bear Dunes and then we're off to Mackinac Island.

Saturday, September 17, 2011

The Michigan Basin

If we could scrape away the Paleozoic, Mesozoic and Cenozoic deposits from the Continents, we would find that the ancient, Precambrian basement rock has a topography of ridges, valleys, plains and basins, similar to what we find on our planet's surface today. One of the basins, centered on the lower peninsula of Michigan, stretches from western New York to eastern Wisconsin and from Ontario, Canada to northern Ohio and Indiana.

Known as the Michigan Basin, this broad bowl has gradually filled with sedimentary rocks from the Paleozoic and Mesozoic Eras; as one might expect, sediments advance in age from top to bottom and, on the surface, from the center of the basin to the periphery. The youngest of these deposits, Jurassic in age, are found in the west-central region of lower Michigan while the oldest surface in Ontario (on the north edge of Lake Huron), across the Upper Peninsula of Michigan, along the eastern side of Wisconsin, in Greater Chicago and in the vicinity of Niagara Falls. Most of the basin sediments have since been covered by a thick layer of Pleistocene glacial till and, of course, by the waters of Lakes Superior, Michigan, Huron and Erie.

Over the next two weeks, my wife and I plan to circle across the Michigan Basin, spending two days on Mackinac Island and most of our time along the Upper Peninsula of Michigan. Since I have been through that region in the past, I generally know what to expect but, like all journeys, the adventure lies in the unexpected. Reports from the Basin will follow.

Friday, September 16, 2011

Maria Visits Newfoundland

After lolling about the Caribbean for a week and then passing west of Bermuda, Hurricane Maria has been racing northward and is expected to strike Newfoundland. The powerful storm will streak across the eastern half of that island province and the Avalon Peninsula should bear the brunt of her 80 mph winds.

Surrounded by the chilly waters of the North Atlantic, Newfoundland is relatively immune to hurricanes and tropical storms; indeed, cold water is one of the major factors known to weaken tropical cyclones. Nevertheless, Hurricane Maria is moving northward at a rapid rate, swept along by an advancing cold front, and is forecast to retain Level 1 traits when she reaches southeastern Newfoundland. After raking this Maritime Province, Maria is expected to dissipate south of Greenland.

As local residents prepare for the storm, one wonders if Jim Cantore is on a flight to St. John's. For the king of weather broadcasting to miss such a rare event is almost unthinkable. After all, we have now passed the peak of the 2011 hurricane season and the opportunity to report from the driving rain of a land-falling storm is rapidly fading.

Thursday, September 15, 2011

Hooked on Competition

Competition has always been the engine of the American economy and we have long been entertained by the competitive nature of sports. But, in recent decades, cable television has introduced an exploding array of competition-based programs to a ravenous, tube-watching public.

Spearheaded by the likes of American Idol and Iron Chef, this programming offers an expanding array of competitions between performers, chefs, bakers, designers, survivers, travellers, daredevils and dieters, among others. In most cases, the competitors are systematically eliminated over the course of the season and the viewing public is often involved in the judging process.

While talents are displayed and hard work is rewarded, these shows are popular due to the drama, turmoil and heartache that accompanies the competition; in other words, viewers tune in to witness the stress of those striving for celebrity and are entertained by the suffering that comes with criticism and defeat. As is often the case, these programs, like much of American television, reflect the dark side of human nature and highlight a distrubing undercurrent in human society.

Wednesday, September 14, 2011

The Big Chill

Thunderstorms rumbled across Missouri overnight as the leading edge of a potent cold front dropped through the State. This morning, that front stretches from Upstate New York to Oklahoma to Montana and a wedge of cool, Canadian air has invaded the Plains and Great Lakes region. Our low in Columbia was 58 degrees F, typical for this past week, but the freezing mark has been reached along the northern U.S. border and, here in central Missouri, we expect a drop to 38 degrees by tomorrow morning.

This widespread chill is winter's first significant advance on the Heartland; the seasonal battle with summer has begun and will continue for the next few months. While we recognize spring and fall as distinct seasons, characterized by a host of natural events, they are, in fact, the products of a restless jet stream which engages winter and summer in a struggle for territory. Having settled in Canada for the past few months, the jet has taken a dip to the south, allowing chilly air to pool behind its broad sweep and igniting thunderstorms as the cool dry air undercuts the warm, humid air of summer's domain.

As it undulates across the country in the coming months, the jet sream will produce ridges of summer and troughs of winter; while not as extreme as the parent seasons themselves, these pockets will bring an alternating pattern of warm and cool weather to much of the country. Over time, the chilly interludes will begin to dominate and, as the jet stream settles near the Gulf Coast, winter will reclaim the Heartland. Until then, we'll enjoy the colorful foliage of autumn, the waves of migrant waterfowl and the crisp, invigorating weather of our slide from summer's oppressive heat to the depth of winter's chill.

Tuesday, September 13, 2011

Nature's Nightlight

Torn from Planet Earth by a violent collision, more that 4 billion years ago, the moon's cratered face attests to its traumatic childhood. Yet, in more recent times, our lone satellite has become a cherished feature of the night sky, a beautiful and tranquil companion that has long inspired mankind.

Unlike the sun, that hurls intense light, stifling heat and ionic waves in our direction, the moon is a calm, reflective body, changing its face but not its mood throughout its monthly cycle. Nevertheless, it has played an important role in the evolution of Earth's ecosystems, stabilizing the axis of our planet and producing the tides that, 400 million years ago, allowed life to colonize the land, and, today, provide vital nourishment to coastal habitats.

On the last two mornings, I watched as the full moon dropped below the western horizon. Unaccompanied by the colorful skies and changing light of a sunset, the moon departs with little fanfare but we will look for her when the darkness returns. Afterall, throughout most of human history, the moon was our nightlight, a source of reassurance amidst the turmoil and uncertaintly of our fragile existence.

Sunday, September 11, 2011

The Nature of Terrorism

Terrorism is the use of fear to control others and to influence their behavior. This tool has been used throughout human history, by warlords, emperors, gangsters, priests and preachers, racists, financial magnates, kidnappers, abusive spouses and dysfunctional parents, among others. In most cases, it is the threat of violence rather than the act itself that paralyzes the victims.

Today, as we commemorate the worst act of terrorism on American soil, we remember the victims, honor the rescuers and renounce the violent actions of the terrorists. Yet, since that horrible event, ten years ago, we have advanced the cause of those perpetrators and have allowed their actions to influence our lives. By rushing off to invade Afghanistan and Iraq, we have recruited more extremists to the anti-American crusade and, by restricting privacy and freedom in the U.S., we have conceded control to the terrorists.

Personal safety is not guaranteed on planet Earth and we can never be fully protected from the action of crazed zealots. One would hope that the U.S. begins to place emphasis on exporting our message of freedom by confining military campaigns to the protection of human rights and by ensuring that our intelligence network does not support those who abuse those rights. The beacon of American freedom was not dimmed by the terrorists on September 11, 2001, but, rather, by our reaction to their violence.

Saturday, September 10, 2011

Vancouver Island Earthquake

Along the Pacific Coast, from southern British Columbia to northern California, three small tectonic plates lie between the Pacific and North American Plates. The Juan de Fuca Plate is the largest, stretching from the center of Vancouver Island to the southern border of Oregon, while the Explorer Plate sits north of it and the Gorda Plate lies off northern California; all three, like the Cocos Plate off Central America and the Nazca Plate along the west coast of South America, are remnants of the oceanic Farallon Plate, most of which has since subducted beneath the North and South American Plates.

On the west side of the three plates, they are spreading from the Pacific Plate along a broken oceanic ridge while, on their east side, they are subducting beneath the North American Plate. Between the spreading zones, each plate also has a transform-fault margin with the Pacific Plate, where the plates are scraping against one another; in addition, horizontal (east-west) faults form the boundaries between the Juan de Fuca Plate and its smaller neighbors. In this complex tectonic region, earthquakes may thus be generated at the subduction zones, along the transform faults or at the faults that separate the three plates.

Yesterday's 6.4 magnitude quake occured off the west coast of Vancouver Island, along the subduction zone and very near the margin between the Explorer and Juan de Fuca Plates. Rather shallow (14 miles deep), it was felt as far away as northern Washington but, fortunately, did not produce significant damage. Of course, there is always the potential for strong quakes in this region and those that occur along the subduction zone could produce a catastrophic tsunami. Hopefully, regularly occuring weak quakes might diminish the risk for such an event.

Friday, September 9, 2011

The Energy of Autumn

Rescued from the intense sun and oppressive heat of summer, we humans and our wild neighbors become more active as autumn envelops the Heartland. Birdsong, while not as feverish as the chorus of spring, reignites on these cool mornings and the call of the barred owl echoes through the woodlands. Sensing the approach of winter, hoarders of all variety are active throughout the day, stocking their dens with seeds, nuts and hay.

Many songbirds are noticeably restless, preparing to depart for wintering grounds, while our permanent residents gather in large, seasonal flocks, roaming about the fields and wetlands. Large herbivores, storing energy for the trials of winter, are also stirred by hormones as their annual rut begins. Taking advantage of their active prey, our native predators, avian, reptilian and mammalian, hunt throughout the day and night, culling the weak and ensuring their own survival as the autumn chill intensifies.

We humans, ingrained with the collective memories of our ancestors, are also energized by this seasonal change. Awakened from our summer stupor, we relish outdoor adventures, stretching our muscles and soothing our minds amidst the colorful autumn landscape. Of course, we also sense the coming threat of winter, harvesting our crops, filling our pantries and, for some, taking part in the seasonal hunts that typify our culture. Like our wild neighbors, we know that the invigorating days of fall will soon yield to a dark, frigid season that, for humans, is uncomfortably foreign to our tropical nature.

Thursday, September 8, 2011

A Miocene Supernova

The Miocene Epoch of the Tertiary Period stretched from 22 million years ago (MYA) to 5 MYA. During that time, ancestral apes and early hominids appeared in Africa, Kure Island (now an atoll) and Midway Island developed above the Hawaiian hotspot, the Columbia Plateau formed from massive basalt flows, Iceland emerged from the sea, the Intermountain West was uplifted another 5000 feet, the Gulf of Aden began to open and the East African Rift started to form. In addition to ancestral apes and hominids, the first true elephants, giraffes, okapis, hippos and North American pronghorns made their appearance.

Two weeks ago, on August 24, astronomers from the University of California observed the sudden appearance of a supernova in the Pinwheel Galaxy, 21 million light years from Earth; in other words, they observed the explosion of a star that occured during the early Miocene. Brightening by the day, the display is expected to peak between September 9 and September 12, when it should be visible with powerful binoculars or a small telescope. Located in the Ursa Major (Big Dipper) constellation, the supernova will appear as a bluish-white star just above and slightly left of the last two stars in the Big Dipper's handle.

When we look at the night sky, we are looking back in time. The light from stars, traveling at 186,000 miles per second, takes years to reach Earth, even from our closest neighbors; Sirius, for example, the brightest star in the sky, is 8.7 light years away (if it exploded eight years ago, we will not know until next May). While the Miocene supernova in the Pinwheel Galaxy exploded 21 million light years from Earth, it was a nearby event relative to the vast expanse of the Universe.

Wednesday, September 7, 2011

Common Mullein

Driving through the American countryside, especially across semi-arid grasslands of the West, one readily concludes that common mullein is native to North America. Yet, this widespread plant, easily recognized by its tall, flowering stalk, is native to Eurasia and North Africa; it was introduced to America by European colonists in the early 1700s and was initially culivated for medicinal purposes.

Favoring abundant sunshine and well-drained soil, common mullein is a biennial, requiring two years to complete its life cycle. Following germination, the plant forms a rosette of large, velvety leaves which persists through the following winter; as the second spring progresses, a tall stalk is produced (often rising 6 feet or more) on which numerous, compact, yellow flowers develop. These flowers, which bloom in sequence from late June through mid September, are pollinated by bees, other insects or wind currents; an abundant crop of tiny seeds, eaten by goldfinches and buntings, remain on the drying stalk through the winter and are eventually scattered by the wind. Able to survive long periods of dormancy, mullein seeds are programmed to await ideal growing conditions and may not germinate for decades.

Like other prolific aliens, such as dandelions and starlings, common mullein owes its success in North America to the human tendency to manipulate natural ecosystems. Once introduced into a new environment, the reproductive potential of alien species is often impossible to contain and, to the chagrin of gardeners, farmers and ranchers, they become naturalized "weeds or pests". Since common mullein is clearly here to stay, we might as well enjoy the seasonal beauty of these tall, sun-loving plants.

Monday, September 5, 2011

Weather and the Seasons

We humans define the seasons by the solar cycle or by our own, somewhat arbitrary calendar. According to the first, more natural definition, the seasons stretch between the solstices and the equinoxes while, on the latter, each is assigned a three month block, based on cultural and religious tradition.

It is, of course, the tilt of Earth's axis that produces our seasonal change, as the angle of sunlight (and subsequent surface heating) varies through the year. While there is limited annual solar variation in the Tropics, there is a dramatic seasonal change at the poles, with periods of perpetual light and darkness; between these extremes, the seasonal variance correlates with latitude but may also be affected by ocean currents or the proximity to large bodies of water, which moderate conditions on the adjacent land.

Nevertheless, as we all know, seasonal weather expectations, based on long term observations, are not always met. Stagnant weather patterns or sudden shifts in the jet stream can produce a spring without rain, a chilly summer or a week of balmy days in the midst of winter. While our wild neighbors respond primarily to the light cycle and readily adapt to changing conditions, we humans are prone to emotional turmoil when the weather and seasons are out of sync. Unfortunately, nature is oblivious to human expectations and we must accept (if not cherish) her whimsical temperament.

Saturday, September 3, 2011

Front Range Upslope

As I packed my truck yesterday morning, it was sunny and mild in Littleton, Colorado. However, I noticed a swath of low clouds across the eastern horizon and the Front Range foothills had taken on a hazy appearance. Before I left the city, heading east, the gray clouds had spread westward, shrouding most of Metro Denver, and the temperature dropped in concert. East of the city, near Byers, I encountered mist and dense fog, which enveloped the highway until I crossed the Palmer Divide; beyond that topographic barrier, as the air was forced to decend, the fog disappeared and breaks appeared in the gray overcast.

The above account is typical of an upslope weather event, which occurs along the Front Range in the wake of a cold front; while the Continental Divide blocks the first band of clouds and precipitation as the front moves from west to east, northeast winds develop behind the front, pushing cool air and moisture toward Denver from the northern High Plains. As the air is forced to rise across increasingly higher terrain, low clouds form and precipitation develops; depending on both the availability of moisture over the Plains and the temperature of the air, this precipitation may be light or heavy and may fall as rain or snow. Once the front moves further east and the upslope flow resolves, the clouds and precipiation dissipate.

Yesterday's system was relatively starved of moisture and precipitation was minimal. I finally caught up with the front itself in western Kansas; while Goodland was raked with chilly, north winds under cloudy skies, Colby, just 30 miles to the east (but still ahead of the front) was sunny and warm, with strong, southwesterly winds. Though many regions of our country claim to experience rapidly changing weather, few compare to the Mountain West, where the varied topography has a dramatic effect on weather systems and where wind direction is often the primary factor when it comes to temperature and precipitation.

Thursday, September 1, 2011

Sharptail Ridge

South of Metro Denver, the terrain gradually rises toward the Palmer Divide and has been sculpted into a maze of ridges and mesas by the tributaries of the South Platte River. Douglas County has set aside one of these ridges as an open space preserve, chosen to protect breeding habitat for sharp-tailed grouse. A parking area off Roxborough Park Road is the access point for a 4.4 mile trail that winds up and along the ridge, eventually intersecting a network of trails in the foothills. From the trailhead, which sits at an elevation of 5800 feet, the trail winds southward and gradually upward, crossing shortgrass prairie studded with yuccas, prickly pear cacti and a wide variety of wildflowers. Grassland sparrows, Say's phoebes, meadowlarks, sharp-tailed grouse and open country raptors, such as kestrels, prairie falcons and golden eagles, are often observed along the way and signs warn visitors to watch for prairie rattlesnakes that may sun themselves on the trail.

As the trail climbs higher, changing views of the nearby foothills, distant mountains and Metro Denver unfold to the west and north. Two miles from the trailhead, near an elevation of 6000 feet, the path reaches a swath of foothill shrublands which blanket the more shaded slopes of the ridge. Here you may find rufous-sided and green-tailed towhees, lesser goldfinches, blue-gray gnatcatchers, black-headed grosbeaks, scrub jays and other avian residents of the lower Transition Zone. Just past this area the trail reaches the crest of the ridge and views extend to other ridges and mesas of the Plum Creek watershed; unfortunately, one also observes that residential developments are spreading westward, toward the foothills, placing emphasis on the importance of Sharptail Ridge and other open space preserves.

Those who plan to visit this scenic refuge are advised that dogs and trail bikes are not permitted. In addition, the preserve is closed to the public during most weeks from mid September to late November, when licensed deer and elk hunting occur in the area. Indeed, elk herds winter along this ridge and may attract mountain lions from the adjacent foothills; other predators include coyotes, red fox and raptors, as mentioned above.