9/13/2021

“Autumn leaves don't fall, they fly. They take their time and wander on

this their only chance to soar.”

– Delia Owens, Where the Crawdad Sings

     A few months ago, I was sitting on the beach next to my 89 year old grandpa, an amazing human being who I have always admired for his righteous character and unwavering generosity. We were having a conversation about my new book when he asked me, “So do you believe in this whole global warming thing?” This question caught me by surprise; not because I didn’t have an answer but because as a nature photographer, I never had a choice to believe in global warming or not. I have seen it happening with my own eyes.

     The effects of global warming become painfully obvious when you return to places year after year, like most of us photographers do. Seeing a glacier dramatically receding in size; watching familiar trees lose their leaves for good and wither away; noticing the summers coming sooner, getting hotter, and dragging on longer while winter fades into a faint memory.

     Besides making you more aware of global warming, there is something profound about living somewhere that you can experience the transitions of the four seasons–something I was oblivious to until I moved from southern California to Utah in my early twenties. One feels more physically, mentally, and emotionally connected to the flow of nature. You realize there is a time for rebirth and growth, a time for carefree play, a time for wondrous observation, and a time for quiet isolation. Without these different stages, the passing of time disappears and life feels stagnant. The idea of “endless summer” may be alluring for some, but I know I need ebbing and flowing periods of both productivity and inactivity–inhalation and exhalation. I thrive on change.

"Notice that autumn is more the season of the soul than of nature."

- Friedrich Nietzsche

     For those who wish to see them, there are many lessons to be learned from nature. For me, fall is a season of mindful reduction; shedding all that we no longer need. It is a reminder to let go and move on. The soft, monochromatic atmosphere and lack of sunlight create a subtle backdrop that allows for the trees to perform one last joyous celebration of color without distraction. It also reveals our distorted perception and fear of death. Natures shows us that death does not have to be horrible or tragic, instead it can be just as beautiful as birth. For someone that lives deliberately and doesn’t squander their time, when death comes it can feel as welcoming as a much needed sleep.

     While I love all of the seasons of this magnificent planet, for some reason I have the deepest connection with fall. It is the season that feels the most like me–mirroring my inner self. Perhaps it's because I was born in the middle of it. It's impossible for me to imagine living somewhere else, where I wouldn't see the array of vibrant colors in the leaves of the maples, oaks, cottonwoods, and aspens that I have nearby. They adorn the trees like blossoms and carpet the yard, sidewalks, and trails with a mosaic of hues. 

     I have many fond memories of rambling alone through dense forests of golden, shimmering aspen leaves. Usually in soft, even light as low clouds filter out the midday sun and the occasional raindrops pitter and patter against my jacket. The cool wet air fills my nostrils with the refreshing and rejuvenating smell of moist earth–wet geosmin–and decaying leaves; the fragrance of fall. For me, there is no better time of the year to be outside. 

     Sadly, due to drought and increasing temperatures, the southwest aspen population has been rapidly dying off in large numbers, especially in Colorado and Utah. This startling phenomenon has been aptly termed SAD (Sudden Aspen Decline) by the forestry service, which has not been able to find any way of preventing it. As each year gets hotter we can expect to see more and more stands of bare, withered aspen trees. 

     The dryness and heat have become clearly evident in recent years. Last year, autumn was especially hot and rainless. Beneath a cloudless sky, I trudged through groves of aspens trying to create photographs as the intense sunlight glared down upon me and the landscape. It felt more like summer really. Without the gradual cues of falling temperatures to allow trees to prepare for winter, by shedding their leaves and drawing their water inward, the leaves stayed green through much of the fall season–creating as much sugar as possible before the long slumber–and abruptly shriveled up and turned brown when winter did finally knock on the door.

     On the other hand, many aspen trees dropped their leaves long before fall. In the last two years, the fall season has followed an extremely warm and dry summer. These two factors play a huge role in how the fall season plays out. Drought inhibits trees from being able to produce as many leaves in the spring, as they do not have sufficient water to do so. So most trees started their year below their optimal condition.

     During heat spells, deciduous trees can actually cool down the forest by several degrees, creating their own air conditioning by sweating out moisture in unison. However, during droughts or extended periods of warm weather, the trees can’t afford to continually cool down this way, and will purposely drop their leaves in order to reduce their surface area. This way they do not perspire as much and lose precious water while being baked in the sun. Just like us, trees will die far quicker from thirst than hunger.

     Aspens actually fare well in constant sunlight due to their pale, white bark, and are intolerant of shade. This is why you don’t often find aspens mixed in with other trees, usually standing in large groups all on their own. Their winged seeds–designed to carry them far away in the wind–are content to adopt barren, logged or burned areas of forest where they may start a new colony in isolation; they do not like to be in the shadows of taller maples, oaks, or pine trees. However, despite their ability to cope with constant sunlight, there is still a point where the heat can become overwhelming for them.

     While lack of water and extreme prolonged heat can indeed kill trees, it has only been a contributor to the recent rapid dieback of aspen trees. The healthy relationship between aspen trees, fungi, and insects has turned lethal as more and more trees become weakened from drought and lose their ability to defend themselves and fend off invaders such as Cytospora canker, poplar borers, and aspen bark beetles.

     The aspen bark beetles normally help out in the forest, by ushering out the dying trees to make room for new life. While they will indeed try to feed on any tree nearby–dying or not–healthy trees can easily fend off bark beetles by releasing pitch, a resin produced by trees that is thicker than sap, to push them back out when trying to burrow in their bark. However, a tree that has been suffering all spring and summer due to a lack of water, is much less capable of deterring these otherwise harmless insects. Bark beetles are also in tune with the kinds of signals that trees send to one another, and can detect when a tree is in distress. When trees on the edge of the forest warn the others of drought through scents and infrasound (sounds that fall below the frequency of 20 Hz, the limit of what we can hear), bark beetles hear it as an invitation for lunch.

     The populations of all the different species of bark beetle have been exponentially increasing in size as well. The devastation of this can be easily seen anywhere in the mountains of Utah, Colorado, Idaho, and now Wyoming and Montana as well, as vast areas of ghostly white pine trees stand dead and bare. Normally, the bark beetles die off in large numbers during the winter season, mainly only leaving eggs behind, burrowed in the warm tree bark to hatch the 

following year. But in order for this to happen, the temperatures have to drop to -20F or so, which has not occurred in most parts of Utah or Colorado for the last couple of decades, even in many high elevation areas. The natural system put in place to cull the bark beetle and other insect populations has been disrupted by rapidly climbing temperatures. Nature will most likely come up with another strategy of keeping the population in check, such as a virus perhaps, but these things can take time, time which trees in an increasingly challenging environment may not have.

     One example of natural population control as the result of a virus happened in western Montana back in 1993. Over the course of a couple of summers, due to warmer temperatures and an abundance of food, the population of a certain “forest tent caterpillar” exploded so much that it was impossible to ignore. Fast population booms like these are referred to in biology as "outbreaks." Caterpillars were in nearly every single tree and their gooey, sticky excrement was falling down all over cars, houses, and sidewalks. Locals that lived through it have said there were so many of them that in the quiet hours of the night their constant munching and excreting would become audible. All the leaves in their wake were devoured and nearly all of the trees in the region stood bare long before winter.

     The following year, to everyone's surprise, there were no more caterpillars. They had simply vanished. David Quammen, a renowned nature journalist who lived through the experience, later realized after investigating the situation that a deadly virus spilled over (when a virus transmits to a new species) to the tent caterpillar population and began to spread like wildfire. Once contracted, the virus would begin to dissolve the caterpillars from the inside, literally melting them into slime. With the trees crowded with hundreds of caterpillars, the virus spread from one to another as infected guts and fluids would drip down onto the other caterpillars below.

     The tall, vertical spike of the rising population was followed by a sharp decline, promptly bringing the forest ecosystem back into equilibrium. While no one can flat out say that this was intentionally done by nature, it does seem to reveal that safeguards are in place to prevent any species from completely wiping everything out. Maybe the virus had already been present for years among some of the caterpillars, but once the population boomed, the virus was able to spread more easily, as the caterpillars didn’t have space to spread out. One may call it coincidence, but for me the ancient intelligence and wisdom embedded in nature is too obvious to ignore.

"One way to open your eyes is to ask yourself, "What if I had never seen this before?

What if I knew I would never see it again?"

– Rachel Carson

     Somehow much of our species has been able to avoid most of the opposing forces of nature–7.5 billion people now serve as evidence of that. We have even been able to overcome natural selection, as the indiscriminate diseases, predators, and weather conditions that used to leave only the strongest, fastest, and smartest (individuals and communities) standing can no longer seem to wipe us out. I think our exponential population growth definitely qualifies as an outbreak. I wonder what kind of an event it would now take to put our species back into equilibrium with the rest of the world–despite our technology, medicine, and engineering capabilities which we have used to repeatedly cheat death whenever it comes knocking.

     The most unfortunate part of human induced climate change is how few of us are concerned about correcting our mistakes and working to reverse the damage we have inflicted on the natural world. It seems the value of keeping ecosystems intact and preserving a diverse range of species is difficult for the majority of us to grasp. Despite our evident destruction and the serious warnings we receive from nature, we continue to trade wilderness with all of its inherent mystery, beauty, space, stillness, and silence for drab concrete structures, noisy highways, synthetic food, and a lifestyle too fast to savor the simple joys of life. We were given a generous world that freely sustained us and we managed to turn it into one that is now slowly killing us with harmful sunlight, polluted air, toxic water, and poisoned food. Progress is the last word that comes to mind.

     I can’t help but look back on past years when trees were healthier, leaves were more vibrant, and rain and snow created an emotive atmosphere. I never truly understood the value of those experiences until it was no longer possible to have them. I always went through the year believing that my favorite season would come, along with all of its beautifully aesthetic and restorative qualities. In 2019 I read David Wallace-Wells's alarming book on climate change, "The Uninhabitable Earth," where he predicted that at some point deciduous trees would cease to show fall colors at all. I remember feeling deeply troubled by this idea, but thinking it was still in the distant future. I never suspected it would start happening just a few years later. All I want now is to experience another fall that feels like fall–with its lovely cool atmosphere and melancholy mood. But I'm afraid those days may now only come to me in memories of the past.

Click Here To See The Gallery: "Faint Memories"