This article is the first in a new PRT series celebrating our area’s natural splendor and heritage. We are interested in publishing contributions from our readers in future installments of “Great Trees of Eastern Santa Cruz County.” Do you know a great tree? Share it with us! It can be any tree on public or private property in Eastern Santa Cruz County. Tell us what makes the tree great: maybe it’s the tree’s size, shape or age; or its leaf color; or the animals and insects who inhabit it; or the special events or family traditions associated with it; or perhaps something more personal. Whatever it is, share it with us. (You don’t have to disclose the tree’s exact location unless you want to.) Please submit photos (or artwork!) and text about your favorite tree to Assistant Editor Jay Babcock at prtadast@gmail.com
My life has been shaped by trees. I grew up back East where a plethora of species towered above me. I gawked upwards at their immensity, climbed them when I could, watched as birds, insects, squirrels and other wildlife worked in their trunks, branches and foliage.
The oaks always stood out to me, many rising to improbable heights, with behemoth girths, covering the ground in acorns come autumn. Trees in general, and perhaps oaks in particular, helped me to cut my teeth as a young naturalist.
Fast forward from my youth to adulthood in the Sky Islands where, once again, I encountered oaks. Of the 13 types of oak recorded in Arizona, not a single species, or likely even a lone tree, can hold a candle to the sheer size of those eastern ones. But our local members of the genus Quercus beguile me with other charms, no less intoxicating.
Having already admired countless individual oaks in the Sky Islands, I found myself exploring along Sonoita Creek, not long after Claudia and I moved to Santa Cruz County in 2008.
The usual riparian forest trees greeted me on my trek: Fremont cottonwood, Southwestern black willow, velvet ash. Nary an oak was to be found. This was not their purview. While Madrean woodland, with its oaks, junipers, and pines lay not too distant in the Patagonia and Santa Rita Mountains, Sonoita Creek was simply not the proper environment to support any Quercus specimens.
As I came to where a north-facing slope framed one side of the creek, my eyes were instantly drawn to the blue-green foliage of a partially hidden tree. At once I realized that I was wrong in my assumption. Here was a Mexican blue oak. A short walk brought me to a mature tree that defied my experience of oaks in other parts of the Sky Islands, which are relatively short-statured, asymmetrical and wonderfully gnarled—nothing like their eastern counterparts. These qualities certainly applied to this oak, but in such a novel fashion that my jaw literally dropped.
The first thing that caught my attention was the size of the tree—not so much its height, though it approached 60 feet tall, which is respectable for our local species. The tree’s crown spread perhaps 110 feet from side to side, making it far wider than tall and overall highly asymmetrical. It was, however, the girth of the trunk that completely captured my attention.
It is standard to measure the diameter of a tree trunk at chest height. Hence the term “diameter at breast height” or DBH. As a field biologist I had measured the DBH of countless trees over the course of my career, including ones far wider than this oak. Nonetheless, in the context of the Sky Islands and within the immediate purview of Mexican Blue Oak, I had never come across such a gargantuan trunk—about 4.5 feet DBH. Furthermore, the first 20 feet or so of the massive bole was almost perfectly horizontal! As it rose out of the ground just before a steep rise, it made a left-hand turn until it finally splayed up into multiple sub-trunks, like a giant squid menacing its tentacles in the deep, abysmal brine. Nature’s hammock, I thought.
Wasting no time, I approached the tree, lounging on its trunk foremost in my mind. Soon, however, I was frozen in place. A familiar buzz put me on high alert. There! About 25 feet high in a sub-trunk was a hole from which honey bees were noisily streaming to and fro. At an elevation of about 4,000 feet, this colony was undoubtedly “Africanized” and hence prone to aggression. I quickly moved away from the cavity side of the tree, which fortunately was sufficiently far from the prone trunk so as not to spoil my desire to laze.
Soon I lay face up on the ample trunk. Gazing up at its oval, blue-green leaves, a number of things struck me. First was the potential age of the tree. Surely this was a venerable elder given its size. True, the creek was about 40 yards away, offering the possibility that the oak’s roots had found the water table, affording speedy growth. Still, oaks are not cottonwoods or willows which can attain great size with blinding rapidity—at least for a tree. I reckoned that this oak was at least 150 years old. Perhaps germinated back in the early or mid 1800’s, “my” tree (for I immediately became proprietary over my new friend) had seen quite a bit over its many decades.
Back when it was young, Mexican grizzlies probably walked past this great Blue Oak. This subspecies of Ursus arctos was present near Sonoita Creek even into the early 1900s. These bears might have scratched their backs against the tree’s strong trunk, or splayed themselves over its prone form when the oak was older. Mexican wolves, also now locally vanished, and jaguars too, must have wandered nearby, given the rich riparian environment. I closed my eyes, envisioning that I was now el tigre himself, perched imperiously upon my oak—master of all I surveyed.
Certainly white-nosed coatis had been recent visitors here, as evidenced by the hackberry-laden scat plopped atop the trunk. Owl whitewash lay on the forest floor underneath the tree. A large, yellowish shelf fungus hung in a crevice not far from the honey bee cavity. It was a species I had never seen before. Other signs abounded, each drawing me into the constellation of lives that intertwined with this particular Quercus ovata.
Then my mind bolted to a sad reality. This tree was one of the last of its kind—an outlier in both age and geography. True, about eight other Mexican blue oaks adorned the north-facing slope for about a 100-yard stretch to the east. But none approached the size or age of this one.
Even more tellingly, over the years I have failed to find a single acorn produced by any of them, and certainly no seedling or saplings. This is clearly a tiny, senescent population that is doomed to perish. While relatively healthy stands of the species populate other sections of the Sky Islands, this one is emblematic of an alarming trend. Namely, that trees are in a wholesale retreat due to human-wrought climate change. Spawned during more favorable environmental conditions—perhaps when an intrepid acorn woodpecker or Mexican jay ventured between mountain ranges, acorn in tow—these oaks, and my specific tree, now are in a wild nursing home. Unable to reproduce, they still add beauty and great ecological value to the scene.
Since meeting my oak—which I have dubbed ‘Panthera,’ after the genus of jaguars—I have returned many times. Soon, I plan to lounge with it for the better part of a day, deeply reveling in its life. It has already alerted me to the changes we humans are affecting on the region. Indeed, I have uncovered a good handful of expired Mexican blue oak trunks—either standing or, more often, lying ignominiously on the ground like so many gravestones—near Raven’s Nest Nature Sanctuary. Having met their demise, they serve as vivid reminders to me of just how tenuous an existence our Sky Island trees live each day. How many droughts and searing summers are we away from seeing their wholesale retreat?
Ask people in other regions of the globe where humanity has already squandered this profound environmental birthright, this incalculable gift from the Earth. In the nation of Jordan, only about two percent of its original forest cover remains. They too once hosted brown or grizzly bears. They too once had wolves, even lions. Oaks are also a mainstay of their remnant forests. Those ex-forests were cut down, over-grazed and used for firewood. Tellingly, we are at about the same latitude as Jordan: 32 degrees North. Perhaps the eastward lean of my oak’s trunk points directly towards that country—one we think of as a desert. This living sign is one none of us should ignore.
For now, all I can do is honor my oak. Admire the feel of its furrowed bark. Watch birds artfully navigate its tangled branches. Marvel at the life it supports and tell it how beautiful it is. Otherwise, I might just cover it in tears.
Vincent Pinto and his wife, Claudia, run RAVENS-WAY WILD JOURNEYS, their Nature Adventure & Conservation organization devoted to protecting and promoting the unique biodiversity of the Sky Islands region. RWWJ offers a wide variety of private, custom-made courses, birding and biodiversity tours. Visit ravensnatureschool.org