Friday, January 16, 2015

The sandstone that fooled the great geologists (but the younger generation needs to understand)

Flaming Gorge Reservoir from the canyon rim.
The Uinta Mountains of northeast Utah and adjacent Wyoming are “a grand sandstone structure” – red sandstone peaks dot the high country, tilted beds are exposed on the flanks, and the Green River flows through the range via narrow canyons with steep sandstone walls.  In 1964 Flaming Gorge Reservoir flooded these canyons, once home of the Ute people.  They say that at night their spirits walk the rims, staring at the water 1300 feet below, trying to rescue drowning memories.

I camped on the rim last fall and sure enough, around midnight two voices woke me from a deep sleep.  But they weren’t speaking Ute.
the broad, massive range is a grand sandstone structure ... considering this formation to be older than Carboniferous, I have given it provisionally a Devonian color on the map1
they are quite conformable with the limestones, which abound in well-defined fossil remains, so they have been referred to the Carboniferous Weber Quartzite group2
I peeked out of the tent but saw only trees and stars.  “Must be dreaming” I thought but then there was a third voice, barely audible above the wind in the ponderosa pines:
I strongly suspect the purplish sandstones to be of Lower Silurian age.  The precise or approximate age of these rocks is a very interesting problem to me, and I regret very much that my time would not permit me to make a thorough exploration of both sides of this most interesting range3
This was followed by a loud and sharp retort:
Your geology is hopeless and your private character bad!4
Tussling and moaning ensued.  Maybe it was just the dog and her blanket but I couldn’t be sure.  However if these were indeed visitors, I now knew who they were – John Wesley Powell, Samuel Franklin Emmons, Ferdinand Vandeveer Hayden and Clarence King – four great 19th-century geologists of the American West.  All had explored the Uinta Mountains.  Now their spirits walked the canyon rims, still debating the age of the rocks below.
“Silurian!” “Carboniferous!!” “Devonian!!!” ... it was a spirited debate!

After the Civil War ended in 1865, American eyes looked west toward the country’s unknown territory – from the Rocky Mountains to the east side of the Sierra Nevada.  Government, commercial interests and individuals all hoped it was a land of riches; rumors, some grossly inflated, fueled the fire.  But no one really knew what was out there.

Four highly-motivated men with strong personalities and good connections saw this as an opportunity.  Each secured funding from the US government to explore, describe and map large parts of the terra incognita.  These were the Great Surveys.  They overlapped extensively in time and space, but were carried out independently and with more than a little competition and acrimony ... not surprising given the personalities involved.  The area was so large and existing knowledge so limited that the "surveys" were perhaps better called reconnaissances or explorations.  Even so they generated massive amounts of knowledge where there was little before, and produced maps of sufficient detail and quality to route railroads, choose farm land, and narrow the search for riches (Bartlett 1962; Hansen 1969, Introduction).
Powell's land cover map of the Green River/Uinta Mountains; green - Irrigable Lands; gray - Pine Lands; darker green - Cottonwood Groves; brown - Copper and Silver Region.  Courtesy David Rumsey Map Collection.

Three of the four surveys included the Uinta Mountains (the exception was the Wheeler Survey).  Each produced a geologic map, and each had to assign an age to the sandstone that dominated the range.  The latter task proved to be especially challenging.

At that time geologists generally dated rocks based on fossils of known age, or based on the rocks’ position relative to others of known age (we assume younger rock strata lie atop older unless there’s been a subsequent disruption).  Unfortunately survey geologists found no fossils in the sandstone that formed the core of the Uintas, and its position relative to known strata proved to be misleading.  In some cases they thought they could correlate the sandstone with rock units elsewhere.  That also got them into trouble.

FV Hayden, 1870  (source).
Ferdinand Vandeever Hayden led the US Geological and Geographical Survey of the Territories.  He had a reputation for wide-ranging but superficial study; some even considered him more of a self-promoting lobbyist than a geologist.  But he productively covered an immense amount of territory, including Nebraska, Wyoming, Colorado and parts of Utah.  In the late summer of 1870, he spent time on the northern slope of the Uinta Mountains where he struggled to understand extensive outcrops of "dull purplish" sandstone.
The succeeding series of rocks I have not found it so easy to locate in the geological scale.  They consist of dull, purplish sandstones, with a series of thin layers of slate and clay, gradually passing down into quartzites (Hayden 1871).
Hayden was a staunch “layer-cake” geologist (Aalto 2005), believing deposition to be continuous through time to produce an uninterrupted sequence of rocks.  He was not inclined to see unconformities – gaps in the rock record due to erosion or a hiatus in deposition.
In all this series of strata, from the red-beds to the oldest quartzites, I was able to detect no unconformability.  The connection of the [dull purplish] sandstones with the carboniferous limestones [above] was perfect, so far as could be ascertained by the eye, whatever may have been the chasm in time.
Based on similarities with rocks elsewhere, Hayden tentatively concluded that the sandstone at the core of the Uintas dated from the Silurian period ...
The texture of the upper beds of sandstone is so much like the Potsdam sandstones, as may be observed in other portions of the Rocky Mountain region, I was lead to suspect that the upper portion might be Lower Silurian.
... yet he also noted its uniqueness.
I have never observed such a series of rocks in any other portion of the West, and am inclined to think they are confined to the Uinta range.  The Uinta Mountains are not far from the Wasatch range, and apparently join on to that range; yet I have passed through the Wasatch range at right angles at different points, and was able to discover no such series of strata.
Hayden’s geologic map of Colorado included part of the Uinta range; the dull purplish sandstone “of Lower Silurian age” was colored dark brown.  Courtesy David Rumsey Map Collection.

Clarence King, 1869 (source).

Clarence King headed the US Geological Exploration of the 40th Parallel.  As well as the usual guides, hunters and other support staff, he enlisted topographers, geologists, zoologists, botanists, paleontologists and more in order to glean every bit of information possible.  King divided his expedition into crews, each with a topographer and geologist.  The Uinta Mountains were assigned to geologist Samuel Franklin Emmons.
SF Emmons (source).

The Uinta sandstones puzzled Emmons too.  He referred to them as quartzites.  Both are present; the quartzite tends towards sandstone, its precursor.
They consist of a lower series of white and reddish, compact quartzites, a middle series of purple, coarse quartzites, and an upper of red and striped sandstones ... they are in general barren of all fossil remains (Emmons 1877).
Directly above the quartzites and sandstones was a layer of limestone known to be Carboniferous in age.  Had deposition been continuous, or was there a gap in the rock record – an unconformity – between the sandstones and the limestone above?  Emmons found no clear evidence of an unconformity, and concluded that the Uinta quartzites and sandstones could be correlated with the Carboniferous Weber Quartzite of the Wasatch Mountains to the west.
as they are quite conformable with the limestones of the Upper Coal-Measure group, which abound in well-defined fossil remains, they have been referred to the Weber Quartzite group.
Reddish sandstones below limestones of the "Upper Coal-Measure group" ... really quite conformable?
Emmons had some reservations about correlating the quartzite/sandstone with the Weber.
Their thickness [Uinta quartzites], as observed in different parts of the range, is from 10,000 to 12,000 feet, while, as their base is never reached, the actual thickness of the formation may be indefinitely greater. This fact might seem to throw some doubt upon the correctness of the assumption that they all belong to the Carboniferous formation, since the Weber Quartzite, in the Wahsatch Range, at a comparatively short distance to the west, attains a development of only 5,000 to 7,000 feet, and the general tendency of all the formations is to thin out to the eastward.
King's geologic map of the Uinta Mountains (by Emmons).  The sandstone/quartzite “referred to the Carboniferous Weber Quartzite group” was colored dark blue.  Courtesy David Rumsey Map Collection.
After he finished his writeup, Emmons learned of discoveries by Powell in the eastern Uintas that cast additional doubt on his correlation of the Uinta quartzite with the Weber.  He was able to insert a footnote before the final report was published (Volume II, 1877).
Since the above was written, there has been published, in the report of Prof. J. W. Powell, on the Geology of the Eastern Uinta Mountains (p. 144), sections made in the cañons of the Green River, showing an unconformity of deposition in these beds, which, if correct, would seem to prove the latter supposition to be the more correct [i.e. the sandstone/quartzite is much older].

John Wesley Powell (source).
The best-known of the Great Survey leaders was John Wesley Powell, head of the US Geographical and Geological Survey of the Rocky Mountain Region.  His pioneering descents of the Green and Colorado Rivers gained him fame far beyond geological circles.  The Green took Powell through the Uinta Mountains, via deep canyons where he saw things not accessible to the other surveyors.
In the many deep cañons and gulches by which the range is cleft, in the many amphitheaters that are found along the crest of the range, and in the mural faces of its lofty peaks, everywhere the sandstones are made bare to the eye of the geologist (Powell 1876).
In Whirlpool Canyon, he saw the sandstones not only made bare, but also lying unconformably under Carboniferous limestone.  The sandstone layer clearly had been eroded before the limey sediments were deposited.
Powell provided a diagram of the unconformity (at red arrow), showing hills and valleys in the eroded upper surface of the Uinta sandstone.  Modified from Powell 1876.
The period of erosion separating the sandstones from the Carboniferous beds above was sufficient to carry away at least 3,000 feet of the Uinta Sandstone in some places. How much more was carried away we cannot say.  To my mind this suggests that the Uinta Sandstone may be considered Devonian—an opinion which I would yield upon the slightest paleontologic evidence to the contrary.
Thus all of the survey geologists assigned the enigmatic Uinta sandstone to the middle of the Paleozoic era, though they disagreed on the exact period.  But all were wrong.  It's actually much older.
On three published geological maps they [quartzites and sandstones] have been assigned successively to as many different periods–on the [King] maps to the Carboniferous, on the Powell map to the Devonian, and on the Hayden maps to the Silurianwhereas in point of fact they do not belong to any one of the three (Emmons 1907).
A clear age for the Uinta sandstones proved elusive ... until Emmons took another look in 1906.   
Time scale based on Encyclopaedia Brittanica Kids (2007).
When he was 65 years old, Samuel Franklin Emmons returned to the Uinta Mountains and the puzzling quartzite/sandstone.  In several canyons where rocks were well-exposed, he saw the unconformity described by Powell from Whirlpool Canyon.  Based on correlation with rocks in the Wasatch Mountains, Emmons concluded that the Uinta rocks were in fact Precambrian.
The Uinta quartzites I regard as undoubtedly of Pre-Cambrian age, and, like most Pre-Cambrian formations in the West, which are widely separated and generally barren of fossils, its exact correlation will for a long time probably remain in doubt (Emmons 1907).
Roadcut in Precambrian sandstones near Flaming Gorge dam.
That winter, Emmons read a paper about his findings before the Geological Society of America.  He took the opportunity to explain to the younger generation the challenges faced by geologists of the Great Surveys.
A generation has passed away since these maps were made, during which time the advance in geological knowledge of the West has been so great and the change in methods of work so radical that it is difficult for the younger generation of geologists to appreciate the conditions under which geological work was then done.
Powell expedition camped in willows near Green River, Wyoming, 1871 (source).
So large were the areas laid out for the field work of each season that the utmost speed was necessary in order to go over the whole ground before snow rendered geological work impracticable.  Thus the Green River sheet, which covers an area of over 15,000 square miles, including the greater part of the Uinta mountains, was completed during the single field season of 1871.
The general system of work was to construct in our minds, from field observations, a tentative set of geological divisions, based primarily on lithologic distinctions  As we had no maps, we used only breast-pocket notebooks in which to record our observations; hence the ideas we formed as to the geological structure ... could not be fully put on paper until the topographer’s notes for the whole area surveyed had been platted and engraved, and our tentative geological columns modified or confirmed by the determination of our fossil collections by specialists.  [This is why it took two years to prepare maps after field work was completed.]
Primitive tools and lack of information were not the only reasons that “conflicting statements were made” by the three Surveys.  Competition and growing friction among the leaders were to blame as well.
When, in the winter of 1874-1875, the working up of our material was so far advanced that we could draw in the geological outlines on the Green River sheet, there was a question as to what color should be given to the great quartzite core of the Uintas.  ...  To correlate it with this formation [Precambrian rocks in the Wasatch Mountains] involved the assumption of an unconformity ... no such unconformity had been observed, however, and one of the rules laid down by Mr King for geological mapping was not to represent any such features as faults or unconformities which were not proved by actual evidence in the field.  Hence, with some misgivings, but as the only alternative, the doubtful quartzite was correlated with the Weber, and so mapped.  That such an unconformity had actually been observed by Mr Powell in the deep canyons of Green River, which we had been unable to explore through want of boats, was only known to us some years later.
"The doubtful quartzite" with Utah juniper, pinyon and rabbitbrush.
In other words Powell had not shared with other survey geologists what he had seen in the canyons of the eastern Uintas.  Emmons was especially upset because he had discussed Uinta geology with Powell after the 1871 field season ... at Powell’s request.
Mr. Powell paid me the compliment of asking me to explain to him my ideas of the Uinta structure, saying that his observations in his boat journeys down the Colorado being necessarily confined to the immediate vicinity of the river, were difficult to coordinate, and he felt it would be of great help to him in working them out to thoroughly understand the Uinta uplift, which was evidently the key to the whole section.  At that time he did not mention the unconformity by erosion ... but in other respects we compared notes freely and agreed in all essential points.
The acrimony intensified when King and Emmons found they were in a race to publish, with Powell in the lead.
after he [Powell] had borrowed a proof-sheet of our topography of that region, it was learned that he proposed to publish a volume on the Uinta mountains in the near future, it was realized that he would probably secure a priority of publication over us.
In a vain attempt to obviate this, Mr King, on November 15, 1875, caused 12 printed copies of the geologically colored Green River basin map, signed and dated in his own handwriting, to be distributed to as many of the leading geologists in the country.  When the Powell report appeared (without any reference to our previous studies) the most important difference ... was as to the age of the Uinta quartzites.
But in the end it hardly mattered.  All of the Great Survey geologists were incorrect about the Uinta sandstone, though that's understandable given the times.  They all made major contributions to knowledge of geology and the American West, yet it wasn’t long before their reports were gathering dust and their maps were obsolete.  As always, science marches on.
Their wonderful maps, compiled after so much physical labor, are now useless, save to historians and collectors.  Richard Bartlett on the Great Surveys (1962)
Map of Hayden surveys; from Special Collections, University of Wyoming Libraries.

to be continued ...

Sources (including footnotes from text)

Aalto, KA.  2005.  Pioneering geologic studies of the Uinta Mountains by the great post-Civil War surveys of King, Hayden and Powell, in Dehler, CM, Pederson, JL, Sprinkel, DA, and Kowallis, BJ, eds.  2005.  Uinta Mountain geology.  Utah Geological Association Publication 33.  [footnote 4 refers to a letter from Clarence King quoted by Aalto]

Bartlett, RA.  1962.  Great surveys of the American West.  Norman: University of Oklahoma Press.

Emmons, SF.  1877.  Uinta Mountains, in Hague, A and Emmons, SF.  Descriptive geology.  Volume II of King, C.  Report of the geological exploration of the Fortieth Parallel.   [footnote 2]

Emmons, SF.  1907.  Uinta Mountains.  Geological Society of America Bulletin.  18:287-302.

Hansen, WR.  1969.  The geologic story of the Uinta Mountains.  USGS Bulletin: 1291.

Hayden, FV.  1871.  Preliminary report of the United State Geological Survey of Wyoming, adn portions of contiguous territories.  Washington:  Government Printing Office. [footnote 3]

Powell, JW.  1876.  Report on the geology of the eastern portion of the Uinta Mountains and a region of country adjacent thereto. [and accompanying Atlas]  Washington: Government Printing Office.   [footnote 1]

Wednesday, January 7, 2015

Am I following a cottonwood of the bitter kind?

The Laramie River is lined with the wrong kind of cottonwood, including mine (left).
... we arrived on the 10th March at a small branch of the North fork of the Platte, where we found an abundance of wood.  This stream is about one hundred feet wide, meandering north-eastwardly through a beautiful and fertile valley ...  It’s margin is partially wooded with large cottonwood of the bitter kind.  The sweet cottonwood ... is nowhere to be found    William Henry Ashley, 1825 (Dale 1918)
Cottonwoods were an important winter fuel in the American West in the 1800s, not just for heat but also to fuel the main mode of transport – the horse.  When grass was poor or covered in snow, the inhabitants – Indians, explorers, trappers and early settlers – collected young branches and inner bark to feed their horses.
Young cottonwood branches and upper branches of older trees were provided as forage for their [Teton Dakota] horses and were said to be as “good for them as oats.”  White trappers and travelers have recorded their observations as to the value of the cottonwood as forage.  (Gilmore 1919)
When the round leaf or sweet-bark cottonwood can be had abundantly, horses may be wintered with but little inconvenience.  They are very fond of this bark, and, judging by the effect produced from feeding it to my horses last winter, I suppose it almost, if not quite, as nutricious as timothy hay.   William Henry Ashley, 1825 (Dale 1918)
Horses survived and even thrived on sweet cottonwood at lower elevations, but they wouldn’t eat the bitter cottonwood of higher valleys and mountains.  In winter a horse would starve in these places.
No sweet cottonwoods anywhere.
Fur trader William Ashley and a small band of trappers camped for several days in the Laramie Valley in March of 1825, while exploring a “central route” to the Pacific.  They had been in the region long enough to know the cottonwoods.  They recognized those along the river as “of the bitter kind” while "The sweet cottonwood, such as affords food for horses, is nowhere to be found" (Dale 1918).

Not all trappers were as savvy.  In the fall of 1831, a party led by Captain AK Stephens chose the Laramie Valley for their winter camp.  Game was abundant, and the river was lined with cottonwoods.  But they didn’t notice that these were the wrong kind until the snows came; then it was too late to move.  They survived, as there was plenty of game and firewood, but their horses didn’t.
My cottonwood tree shortly after new-years day, 2015.
On new-years day, notwithstanding our horses were nearly all dead, as being fully satisfied that the few that were yet living must die soon, we concluded to have a feast in our best style; for which purpose we made preparation by sending out four of our best hunters, to get a choice piece of meat for the occasion. These men killed ten Buffaloe, from which they selected one of the fattest humps they could find and brought in, and after roasting it handsomely before the fire, we all seated ourselves upon the ground, encircling, what we there called a splendid repast to dine upon. Feasting sumptuously, cracking a few jokes, taking a few rounds with our rifles, and wishing heartily for some liquor, having none at that place we spent the day.  Zenas Leonard, 1832 (Leonard 1904)
WY Game & Fish also mistakenly assumed that cottonwoods along the Laramie River were of the sweet kind.
Today we call the sweet cottonwood “Plains cottonwood” or Populus deltoides ssp. monilifera.  The bitter one is the narrowleaf cottonwood, P. angustifolia.  Historians have assumed that early travelers such as Ashley found narrowleafs along the Laramie River (e.g. Dale 1918).  However the cottonwoods I’ve found there appear to be the lanceleaf cottonwood, Populus x acuminata, a widespread natural hybrid between the Plains and narrowleaf cottonwoods.

Below are leaves from the three cottonwoods.  From top to bottom: sweet Plains cottonwood (source), bitter narrowleaf cottonwood (source), and a cottonwood from the Laramie River – probably the hybrid lanceleaf, with broader blades and longer petioles.
When a bitter narrowleaf cottonwood crosses with a sweet Plains cottonwood, what's the result ... bitter or sweet?
Maybe I'll recruit friends to taste the inner bark of the three cottonwoods.  We could do blindfold taste tests ... how scientific!  But will I find any such intrepid companions?
Was it lanceleaf cottonwoods that the trappers camped in, finding them as bitter and unpalatable as the narrowleaf “parent”?  Or did they camp among narrowleafs – the true bitter cottonwoods?  To answer this, we need to know where specifically narrowleaf and lanceleaf (hybrid) cottonwoods grow in the Laramie Valley and vicinity.

I thought this would be easy to figure out.  In Laramie we’re lucky to have the Rocky Mountain Herbarium, at the University of Wyoming.  It's the largest herbarium between St. Louis and those on the West Coast, and the largest anywhere for Rocky Mountain plants.  The local area is generally well-represented, yet when I looked for lanceleaf cottonwood specimens from the Laramie Valley, I found only four ... and none from the river.  Most were collected on the university campus.  There was one specimen of narrowleaf cottonwood from the river, upstream in the mountains to the west.

This summer when mature leaves are available, I’ll collect a specimen from my cottonwood and add it to the Rocky Mountain Herbarium, thereby immortalizing the tree!  Hopefully I can decide what this cottonwood would best be called.  Is it sufficiently different from the narrowleaf to be called a lanceleaf?  With back-crossing, every variation is possible.  If time permits, I’ll visit other places along the river to see which cottonwoods grow where.  There's so much to learn ...
The distant cottonwood (center) is the tree I’m following.

Was my tree alive when Ashley traveled along the Laramie River in 1825?  Did Stephens and his trappers spend the winter near it in 1832?  If so, it would have been a young sapling or sucker shoots.  Cottonwoods grow fast and generally die young, only occasionally reaching 100 years of age or more (Weir 2014).

I’m grateful to Steve Sutter, Cultural Records Specialist with the Wyoming State Historic Preservation Office, for introducing me to the role of cottonwoods in early exploration of the American West.  A simple question – "what kind of cottonwood grows along the river?" – and the discussions that followed made this post possible.


Cain, K.  2007.  The cottonwood tree; an American champion.  Boulder, CO:  Johnson Books.

Dale, HC, ed.  1918.  The Ashley-Smith explorations and the discovery of a central route to the Pacific 1822-1829.  Cleveland: Arthur H. Clark Co.  Available at Google books.

Gilmore, MR.  1919.  Use of plants by the Indians of the Missouri River region.  Bureau of American Ethnology.

Leonard, Z (Wagner, WF, ed).  1904.  Leonard's narrative, adventure of Zenas Leonard, fur trader and trapper, 1831-1836.  Cleveland: The Burrows Brothers Company.  Available at Google books.

Thybony, S.  1981.  The enthnohistory and prehistory of the Medicine Bow National Forest in Eckles, J ed.  Cultural resource overview; Medicine Bow National Forest including the Thunder Basin National Grassland.

Weir, SK.  2014.  Plains cottonwood (PDF).  Accessed January 5, 2015.
Join the fun ... follow a tree!  Kindly hosted by Lucy Corrander.

Thursday, December 25, 2014

Best Wishes from Plants and Rocks

Lanceleaf cottonwood, Laramie River.

Another year of blogging is almost over.  I’d like to thank all my colleagues in the blogosphere ... those who read and those who write ... those I know (a little) and those who remain anonymous.  I’m still in awe, impressed by the new opportunities the internet provides.  Four years ago I knew nothing of blogging.  Now it’s an important source of information, and a most satisfying creative outlet.
expression is the need of my soul (archy)

“Bloggers are saturating the globe” wrote William Zinsser, as he too contemplated today's widespread revolution in writing – powered first by the word-processor and then by the internet.  “I had no inkling of the electronic marvels that would soon revolutionize the act of writing ... for people who had never thought of themselves as writers.”

It's a wonderful revolution, with a happy democratic outcome.  We don't have to be professionals to struggle to put words together and share our masterpieces.  Now we common folk carefully craft stories, add photos beautifully backlit on the monitor, and cast them off into the Unknown, with no assurance that anyone will read them.  And we keep doing it ... for diverse and mysterious reasons. 
Maybe when we tell stories we make memories more vivid and lasting.

I learn a lot from bloggers – about botany, ecology, geology, photography, places to go, things to see – all of it spiced up with excitement and enthusiasm.  Used to be I had a small circle of friends to swap plant and rock stories with.  Now the circle is vast.  To all, happy holidays and best wishes for 2015 ... and keep blogging!
Ice on the Laramie River.


marquis, don.  1927.  archy and mehitabel.  doubleday.

Zinsser, William.  2007.  On writing well; 7th ed.  Harper Collins.

Plants and Rocks is taking a short winter break, returning in a few weeks.

Monday, December 22, 2014

Street Plants in Laramie in December?!

From asphalt and snow, some grass will grow.
When Lucy suggested we post about street plants four times a year, I was not optimistic for December.  We live at 7000 ft elevation in the continental interior, far from the equator.  I set out looking for an escaped juniper or pine tree, that seemed my best bet.  I didn’t find any, but in the process I learned that I hadn’t given our herbaceous plants enough credit.  Some stay green through the winter.  I wonder if they photosynthesize on sunny days, when they’re not covered with snow?

The Easter daisies (Townsendia hookeri) in my garden and out on the prairie keep their leaves through the winter.
An Easter daisy’s version of green.  Plant is six inches across.
There’s still a bit of green grass along the Laramie River bike path.
Green grass tips (look close).
The willows are dormant now, but come spring they will keep working to break up the asphalt and reclaim their habitat.

Yesterday afternoon I made a reconnaissance around the old packing sheds across from my house, thinking there might be a protected spot where a plant waif could grow.  But no, everything was dead ... except ...
... in a driveway a flash of green stopped me.  Not only were there green leaves, there were flowers too!  But the light was low, the wind was howling, and I left photo-less.

This morning was calm, not even a breeze.  About a half inch of snow had fallen overnight, so I brushed it away until I relocated the knotweed.
Prostrate knotweed, Polygonum aviculare.
Prostrate knotweed is a very common weed, quick to colonize disturbed habitat.  Several sources note that it’s adept at colonizing cracks in sidewalks and streets.
Sometimes prostrate knotweed grows upright too.
Optimistic (green) knotweed and grass.

The snow was not helpful in shooting closeups, so I collected a sprig of knotweed to take home for portraits.
It's called “knot”weed because the stem nodes are swollen (click on image above).  The Greeks called them “many knees” – hence the name of the genus:  Poly-gonum.
Short branches at base, with green and white flowers.
Swollen stem nodes, each with a leaf and flowers.
Prostrate knotweed flowers are 4-5 mm long.

For more on street plants and their fans, check out Lucy’s December street plants gathering.  And rejoice! the days are getting longer :-)

Friday, December 19, 2014

Recommended reading: “Photographing Trees”

the air frost and heavy mist offered the potential for creating a great winter scene ... I left lots of room around the tree to make the photograph more saleable.  There is space above and below for a title and sub-titles:
The title is apt.  Foreground, background, frame and viewpoint ... aperture, shutter speed, focus points and ISO ...  trunks, bark, leaves, trees and forests ... all are in Photographing Trees by Edward Parker.  He emphasizes that the book is for photographers of all skill levels and camera types, not just pros with expensive gear.  I agree; the discussions seem very accessible, and the book is full of encouragement and inspiration.
photographs that are useful for your own purposes and that give you a real buzz ... are marks of success
Boxelder in a sandstone canyon, Grand Staircase - Escalante National Monument.
Quaking aspen in the Enchanted Forest, Laramie Mountains.
You don’t have to own a DSLR camera to enjoy this book.  Much of the content also applies to compacts; phone photographers will find some useful tips as well.  Parker takes pains to explain when a compact works as well as a DSLR (and is easier to use).  He repeatedly points to the importance of the photographer’s eye and mind, rather than the camera.
Abstract image of ancient bristlecone pine, White Mountains, California.
The book begins with a brief introduction to digital cameras, followed by the first major section, HOW TO IMPROVE YOUR PHOTOGRAPHS.  This currently is my favorite part of the book.  Composition, Light, Viewpoint ... these are things that make me look at the natural world differently, and make photography so satisfying.
It’s well worth spending time seeking out an interesting viewpoint ... 
Peeling bark of paper birch in Dugout Gulch in the Black Hills.
Foreground is important, even in great sweeping scenes ... [it] helps to make sense of the vast scale of the scene.
Sparky contemplates the vast scale of piñon - juniper woodland in the Great Basin.
line up the shot so the background is in deep shade.  This allows the brightly colored leaves to stand out against a non-distracting black ...
Vine maple, Lake Easton State Park, Cascade Mountains.
Take a friend with you ... to include as scale.
Coast redwood with friend for scale; Pfeiffer Big Sur State Park, California.
I was surprised to find an entire subsection devoted to “Organisation and planning ahead” – not something I do before heading out with my camera.  But how obviously useful it would be to consider the weather forecast and time of day, and their effects on light.
I particularly like it when light from a low sun falls across a subject ... [making] for highlights and shadow areas, which provide visual clues to the let the brain understand a scene ... 
Dead bristlecone pine in low warm evening light.  Light and shade provide clues as to its shape, “helping the brain to understand”.

HOW TO TAKE CONTROL OF YOUR CAMERA is the second major section.  Parker makes clear that it’s not essential.  Everything in IMPROVE YOUR PHOTOGRAPHS can be done in automatic mode ... my usual strategy.  But the explanations of exposure compensation, aperture priority, shutter speed and other tech issues are clear and even persuasive.  I need to give them an honest try, having only dabbled in my DSLR’s technology so far.
When a scene contains a lot of white I find it's often best to overexpose by one stop (move the exposure compensation to +1).
The snow confused my camera’s metering system.  I should have helped it by using exposure compensation.  Some improvements were made with iPhoto, but not what was needed.

The final section, HOW TO PHOTOGRAPH TREES, is a series of photographs with explanations of  “decisions behind the final image” ... decisions based on knowledge from earlier sections.  It's organized by tree features: whole tree, trunks, leaves, bark, fruit, seeds and flowers, woods and forests.
Usually the most obvious approach to photographing a tree is to try and get the whole subject in the frame.  Publishers love this sort of image, but in many cases it can be quite difficult to achieve.
I’ve yet to get a satisfying photo of this contorted old limber pine growing out of a granite crevice.
Tree trunks are the tree photographer’s friend. ... It can be blowing a gale or as dark as night but it is still possible to get an interesting image.
Western red cedar; Ross Creek Giant Cedar Grove, Montana.
Filling the frame edge to edge helps to concentrate the eye ... 
Ponderosa pine cones – two from this season (purple) and one from last year; Laramie Mountains.
... consider clipping off a small sprig so you can set up the photograph indoors or in an area where the light is perfect or the wind less of a problem. 
Young leaves of my lanceleaf cottonwood – in the kitchen, out of the wind.
Parker's book is filled with photographs – beautiful, fascinating, awe-inspiring images of trees from all over the world.  There's nothing wrong with just looking at the photos.  They're full of ideas themselves, and maybe you're like me ... I pay closer attention when I ignore the text.

Photographing Trees costs $20 to $30 for new and nearly new copies.  Based on the number and quality of images alone, this is a bargain.  And the ideas and encouragement that it provides this particular aspiring photographer has made it a treasure.
... there is so much more to photography than just owning expensive equipment; it’s more a way of looking at the world.
Trail into a magical forest of coast live oaks, growing low and twisted to avoid sea winds; Los Osos Oaks State Natural Reserve.
Grassy foreground leads the viewer to a coast live oak and memories of childhood; near San Luis Obispo, California; courtesy Giovanni LoCascio.