Friday, January 23, 2015

Original Face and the Ancient Seas

     Superior, Arizona, just a couple of miles east of the BTA, sits at the base of a geological formation known locally as Apache Leap. The cliffs of the Leap are composed of a dark volcanic tuff squeezed from the earth’s bowels around 25 million years ago.  In the hills beneath the cliffs, one sees layered bands of gray sedimentary rock – once a seabed but now faulted limestone – having originated during the Carboniferous Period. In this limestone, one finds the remnants of organisms that populated the ancient seas – mostly brachiopods, bivalves, and crinoids. 

     My partner Lori and I hiked up to study a few of those limestone outcroppings. We found a slab about 30’ long and 8’ high, composed mostly of a dense conglomeration of fossilized shells. We walked along that wall, brushing our hands thoughtfully across a solidified expanse of time.

     For me, fossils demand some reflection. Their antiquity – 300 million years in the case of these shells – is enough to warrant a few minutes of awe-struck wonder. When these marine creatures were alive, there were dense forests of trees and ferns that eventually became the coal deposits on which much of industrialized mankind depend. There were also insects back then, and fish, and millipedes six feet long. These bivalves and brachiopods were also alive when the most “advanced” land animal was a type of amphibian. Even if the bivalves had had our consciousness (which, of course, they did not), they could still not have imagined that their forms would be covered in mud, replaced by minerals, buried beneath the roiling earth, and then pushed back up and uncovered, only to be marveled over by a species of primate. Beside this cracked gray monolith of shells, I was reminded of the Zen koan, “What was your face before your parents were born?”

      There is a twisting string that goes back, long before these marine animals existed, connecting us all by chemical alignments allowing seemingly infinite variation. This three and a half billion-year-old string has frayed, with minute strands bending in different directions and many strands being cut entirely by catastrophic events, but here we are, barely standing, with binocular vision and swiveling heads and brains containing 86 billion neurons, studying a wide and uneven terrain. I touched the ancient fossil shells and realized I was also touching a part of a shared lineage to all living things.  I was, in a sense, seeing my original face.  

     Wistfully I wondered: How can the abstract and poetic latitudes of our thoughts ever be preserved in the turbulent pressures of time? I don’t think papyrus or a thumb drive will last as long as these shell fragments. My consolation was that, momentarily, for whatever it was worth, I could ease myself against a relic of earth’s biological and geological magnitude and not feel intimidated. 

- T. Stone

Tuesday, January 20, 2015

Geology Tourguide and ASU Professor Steve Semken

Why is our "Rocks of BTA" walk so enduringly popular? Even during the hottest summer months this geology tour consistently draws dozens of enthused attendees. One of our charming rock-jock tour guides may have said it best a few years back when interviewed: "Deep down we all know that geology is the most exciting subject on this planet—and  perhaps all planets. Anyone with a basic understanding geology can look at any mountain that surrounds them and begin to understand the true diversity of nature and depth of time."

Then again, our charismatic guides are a draw: adventurous ASU Professor Steve Semken, plus two professional geologists, Scott McFadden and Rich Leveille. Tempe resident Steve Semken teaches geology and sustainability science and has been a professor at ASU since 2003. Geologic research has taken him around the world from New England to Inner Mongolia. We caught up with this globe-trotting geologist who says most of his most enthralling rocks and landscapes are right here in Arizona. He's a volunteer with the AZ State Parks system, guiding geology walks at Boyce Thompson Arboretum (check the updated schedule at  and included with $10 park admission.

Q. Why is Arizona a great place to be in your line of work?
The one-word answer is exposure. Our arid climate means that a lot of Earth’s crust is visible at the surface and easier to study! But what really makes Arizona unique is its magnificent diversity of landscapes, rocks, and ecosystems. It’s kind of like three states in one: northern Arizona and southern Arizona have very different topography and exposed rocks, as do the rugged central highlands lying in between. The Superior area, including the Arboretum, is especially interesting because it is located at the boundary between two of these major topographic regions, so there’s a lot of variation in a short stretch.

Q. Did you collect rocks when you were a kid?
Yes, from early on. I was born and reared in northern New Jersey. New Jersey has amazing geology, but most of it is covered up by vegetation or civilization! Luckily for me, my parents bought me a membership to a rock and mineral club, and I was able to take many memorable field trips and hikes into places where you could actually see and collect rocks, such as the Franklin mining district, which is world-famous. Many people don’t know that New Jersey was a hard-rock mining state for much of its history…it provided iron for George Washington’s army. Another key thing my parents did for me was to give me a big illustrated Golden Book of Geology, not long after I learned to read. That book made a huge impression on me, and I still have it on my office bookshelf.

Q. What's the focus of your research at ASU?
My primary field is called ethnogeology. It’s a new specialty that combines geology, geography, and anthropology. My students and I are very interested in learning how different cultures understand and interact with the Earth in their homelands. That research goes back to my previous job, teaching geology at the tribal college of the Navajo Nation. My students and I work mostly in the Southwest but also in some parts of Latin America.

One of our major goals is to use our findings to help encourage more diverse students to pursue careers in geology. Another is to use different perspectives to promote more sustainable living in our desert environment.
I also do geologic research in the field in northern and central Arizona with my students. You might be surprised to know how much more we still have to learn about the geologic history of our home state. I never get tired of teaching about southwestern geology.

Q. What are a few hobbies or interests outside of geology ?
Hmm…it’s kind of hard for me to separate work from hobby because most of my pastimes involve being outdoors in the deserts or mountains.  And one of the perks of being a field geologist is getting paid to work outdoors in beautiful places! But I’m particularly fond of river rafting, camping, and hiking with my wonderful wife jeanne and our dog Sancho. BTA is a favorite place for the 3 of us to go. I don’t turn the geologist part of me off when I’m out on a hike or rafting a river for fun, and I appreciate jeanne’s forbearance (and interest) when I get a little nerdy at a rock outcrop now and then.  Some of my other passions are cooking, wines, tequilas, and Sun Devil football.

Q. What are two charismatic rocks you point out on Arboretum tours?
All rocks are interesting to geologists because they tell stories about the Earth. I’d say the coolest rocks are the ones that are “in your face” with their stories—they have features that people can readily see and interpret. Among my favorites are the big freestanding blocks of grey schist near the Smith Building.  Schist is a crystalline rock that forms deep in the crust and records the very origins of continents and mountains. You can see grey schist exposed as you drive through Gonzales Pass west of the Arboretum. That rock tells the story of the original formation of Arizona’s deep crust, about 1800 million years ago.

But I think the coolest rock of all at BTA is the volcanic breccia exposed in the bed of Silver King Wash where the Chihuahuan Desert Trail crosses. Breccia is made up of big chunks of rock expelled by a volcano and welded together. The breccia in Silver King Wash has fist-sized chunks of white pumice set in a matrix of tan volcanic ash. Rock like that is direct evidence of the violent volcanic eruptions that occurred locally about 20 to 18 million years ago and also formed the Superstition Mountains and Picket Post Mountain. I always end my geology hikes at that spot in the wash.

Saturday, January 10, 2015

Hashtags? And the Arboretum

At this point you are likely taking part of the 3.5 Billion searches that occur on google each day. When you search for something using a search engine you will type a phrase, or more specifically you will be typing key words into the search bar. In turn you will be presented with results based on those words. The better your key words are, the better your results may be. This is where the  Hashtag system  becomes relevant.

Hashtags are identified by what we in the United States and Canada know as a pound or number sign at the beginning of a specific word. This method of notation is to enable users of social media to create key words to help people search for whatever it is they post.  Living in this era you likely have heard someone say, “hashtag” followed by something related to whatever it is you are being presented. “Hashtag Reading”, “Hashtag Blog”, “Hashtag Hashtagging”… These are but a few possible examples. Hashtag basically means “key word” if you haven’t caught on yet. But why is this feature so important to us? Well, with this tool you can share things with the Arboretum! If ever you should post something that is related to Boyce Thompson Arboretum, we have a unique key word you can use! That key word is, “1Arb”, The proper notation when you type it will look like this, 

“ #1Arb  “

 Remember to make your hashtags all one word placing the hashmark just before the first letter of any given word you are choosing to make into a key word. This way any time you or anyone else searches within social media for #1Arb and other key words you designate!

Question: Do you personally call the symbol “#” a pound sign, hashmark, or number sign? Let us know in the comments.

Monday, January 5, 2015

The Second Half of Spring

Editor’s note: This article was originally printed in the May 2010 issue of the Newsletter for Members. The accompanying table of flowering times has been updated for 2015.  

The second half of spring, that is to say, April and most of May, is not for the timid. The perennial plants that flower and fruit during these late spring months are case-hardened desert dwellers that never ask for a break from the heat and wouldn’t get one even if they did. They have no desire to be the wimpy annual wildflowers that germinate in the fall and spend a couple of leisurely winter months growing fatter each day before conveniently flowering and completing their life cycle just as the going gets rough in the first few weeks of April.

Late spring perennials are more trustworthy than annuals too, with far fewer boom or bust cycles. Spring annuals are prone to throw uncontrollable temper tantrums by sometimes never germinating at all or scaring everyone by holding their breath and not germinating until January like they did this year. Blessed with a more mature persona, late spring perennial plants have less to prove. They’re perfectly willing to benefit from the same moisture and growing conditions that annuals enjoy, yet they’re willing to admit that they owe much of their physical fitness (good or bad) to the growing conditions of previous years. To be fair, even though annuals can be trying at times, their performance is held hostage by the whims of the current season’s weather.

Brittlebush, Encelia farinosa, is a bit smug because it is a crossover. It’s a perennial plant that can germinate and grow in great quantities like an annual, covering entire hillsides in a near monoculture of yel-low flowers in April, like it did in 2008 and 2010. And then, to leave no doubt as to its well-rounded char-acter, it hunkers down with the rest of the surrounding jojobas, chollas, creosotes, prickly pears, and palo verdes, and stays the course, bravely taking on the brutality of six months of summer. Its Achilles’ heel is its lack of frost tolerance, but it makes up for this trifling handicap with a fast spring recovery and a reputation as one of the Sonoran Desert’s most drought-resistant plants.

Over time, the perennial plants of the second half of spring have developed an attitude and who can blame them? They prove their beauty and unflagging resolve year after year, yet they’re underappreciated by the great proportion of year-round residents that quickly trade refrigeration for perspiration and seasonal residents that flee aridity for humidity. It’s quite possible that most long-time winter residents that have been coming to Arizona from Minnesota or Alberta for a dozen years may have never seen a cholla flower, or the velvety orange petal of a mariposa lily, or even the magnificent white flowers crowning Arizona’s most famous cactus. These gems and many others like them are reserved for the rest of us who don’t have the good sense to beat the heat.

Even with the best of intentions, life cycles progress quickly in the desert and it’s easy to miss the passage of flowering events without some measure of predictability. Who wants to wait until next year? Rules of thumb work to a degree, such as the fact that the flowers of foothill palo verdes always follow blue palo verdes, and ironwoods and saguaros usually flower about the same time in mid-May. Better still is a chart that summarizes flowering events over time.

This table has been updated as of January 2015 and includes both annuals and perennials during the entire spring and early summer wildflower season.

A Decade of Wildflowers

Editor's note: This article was originally printed in the February 2010 issue of the Newsletter for Members. 

Spring wildflowers are notoriously localized and hard to quantify. Wildflower seasons are easier to describe, but both lend themselves to fanciful hyperbole, mainly because their emotional impact often overshadows the reality on the ground. There is morbid silence or low grumbling during poor wildflower years, but in great years, like 2001, it’s not unusual to hear a field botanist fawn over a hillside of Mexican goldpoppies with the same adjectives as a Grand Canyon visitor might use at his first look over the South Rim.

Emotional descriptors like “amazing” or “incredible” or even “mind-bending” don’t add up to much when appraising the last decade of wildflowers in the vicinity of Boyce Thompson Arboretum. For that, I had to sift through the detailed field notes that I’ve kept over the years, skip over the plethora of oohs and aahs, and try to drill down to the nitty gritty of what was actually observed.
But what sounds easy really defies scientific methods: wildflowers are impossible to count, difficult to measure, and there is generally no easy baseline to compare them year-to-year. So, anecdotal appraisals inevitably rule, with comments like the one that I wrote for Mexican goldpoppies in 2001: “Easily the best in 23 years.” Seven years later, I noted that the brittlebush display on the hillsides across from the entrance to the Arboretum was the best in 20 years.

Neither of these references to great seas of orange and yellow would do much to impress a twenty-year-old sophomore botany major who is too young to have his own historical context. I made a better attempt by writing that the west-facing slopes of hills near Silly Mountain “appeared to morph from an opaque dressing of poppy orange to clear, brittlebush yellow in mid-April of 2008”—at least this description infers that poppies bloom first, that they are orange-ish, and that they are eventually forced to hand over the reins to the more heat tolerant brittlebush. 

Not every year is a great season, and 2002, 2003, and 2007 proved to be real stinkers. The years 2004 and 2006 were spotty and forgettable. 2009 was a little better, favoring yellow fiddlenecks, purple bladder pods, and a respectable smattering of the usual suspects, but it lacked the large masses of anything in particular. The years 2001, 2005, and 2008, however, are why we risk sunstroke, dehydration, and basal cell carcinomas and venture out into the desert.
The sweet spot for the timing of annual and herbaceous perennial flowers is generally mid-March to mid-April, but the ideal rain to generate these flowers is generally hoped for in October and November of the previous year, nudged along by rain every few weeks until spring. When looking at weather records for this decade on month-by-month basis, the Arboretum was blessed with copious amounts of rainfall in October and November of 2000 and 2007. Good rain in in the 2004-2005 season, however,  was skewed more toward January and February.

The bottom line is that even though 2001, 2005, and 2008 all fall within the good-to-great category of wildflower shows, 2005 was different, favoring different wildflower species in different densities, sizes, and locations, while sharing some similarities with 2001 and 2008.

The envelope please…

The year 2001 was the season of the Mexican goldpoppy, with hillsides covered from Apache Junction to the Arboretum, and from Globe to Roosevelt Lake, with picture post card masses at the foot of the Superstition Mountains near Lost Dutchman State Park. Nearly every common wildflower on the desert menu was represented, not just in enormous combined masses, but with super-sized individual plants that feasted on the adequate—and well timed—moisture.
The 2005 season favored tremendous stands of brittlebush. Owl clover blanketed some hillsides in poppy-like numbers. Many individual plants of cheeseweed (Malva neglecta) were five feet tall and ten feet across. Scorpionweeds grew to a whopping four to five feet high in places and would have toppled over had they not been supported by surrounding jojobas and creosotes. It was  also a good year for desert lupines, but with scant crowds of goldpoppies.
Wildflowers in 2008 were more like those of a subdued 2001, but with some exceptional standouts. Mexican goldpoppies covered many hillsides in the same areas as 2001, and brittlebush was more profuse and showy than any other time in the decade. Scorpionweed covered slopes above the Queen Creek tunnel and freakish sizes and numbers of desert hyacinths, aka blue dicks, were everywhere, some nearly three feet tall and mixed in cryptically with the similarly colored desert lupines. This was also a good year for the lesser known Gilia scopulorum.
The outcome of 2010 is still up for grabs. Less than two inches of rain fell during October, November, and December of 2009, then seven inches fell on the dry ground in the third week in January. As of mid-February, the desert floor is green, but it’s still too early to tell which wildflowers will rise (or fall) in the last spring wildflower stand of the decade.