[Editorial note: This article was originally published on my old website on October 15th, 2009.]
If you spend a lot of time outside, and consider what you see, you’ll notice a lot of oddities which are hard to fathom. I enjoy these mysteries of nature, and they’ve been one of the longstanding themes in my photography.
Today, I’ll share a couple with you.
Above is the very first picture I took, when I took up photography, a picture of a frozen puddle in Tuolumne Meadows, in Yosemite National Park, in California.
How did it form with these concentric rings? I don’t know, though I have some hypotheses.
First, I’m guessing that this puddle froze from the edges toward the center. It makes sense to me that it would’ve frozen from the perimeter inward, because the edges of the puddle are the shallowest parts, and the water in the shallowest regions should adjust to the ambient temperature quickest. It’s like when you swim in a lake in early Summer: when you step into the ankle deep edges of the lake, the water is warm; when you get where it’s deep enough to swim, it’s freezing cold.
Second, I know (since I was camping there) that the air temperature was hovering around freezing overnight, a little bit below freezing, then a little above freezing, then a little below, again, and so on. So I’m guessing the the water froze discontinuously, on-again, off-again, throughout the night.
Thirdly, I’m guessing that the water was slowly percolating into the ground, while the puddle was freezing. I’m pretty sure of this, since the area under the frozen sheet of ice was hollow.
So, putting it all together, the water slowly lowering while freezing from the edges inward in interrupted stages = the formation of concentric rings.
But that’s just a wild guess.
[UPDATE: Upon closer examination, it looks like the left middle area shows outer lines coming to a halt where they meet inner rings. This appears to rule out the hypothesis that this pattern formed from the edges toward the center. While I would like to imagine that the parts of my hypothesis about percolating water levels and the temperatures hovering around freezing might still be correct, I'm having trouble thinking of a way that those could cause this pattern to form from the center, outward. Thus, I'm back to square one, with no plausible explanation for this pattern's formation.]
This second picture is the very last, most recent picture I took, a quick, documentary snapshot on the hike from Rainbow Falls, a few days ago. It shows a forest where all of the mature trees are missing their tops.
How did they lose their tops? I don’t know, but I have some guesses.
At first, I thought it must’ve involved an avalanche. I’ve seen other cases where avalanches have done similar. First, the bottoms of the trees will be buried under ten or twenty feet of snow, holding the lower trunks securely in place. Then, an avalanche will pummel through, above that layer of snow, and tear off the tops of all the trees.
But that couldn’t have been the case, here. The area where the trees are missing their tops is too large (thousands of acres), and there’s no steep slope above them, nor matchstick-pile of snapped tree tops in a gorge, below.
This area was subjected to a big forest fire in 1992. I have to assume that played a significant factor in removing the tops of the trees. But how?
First, I’m guessing that the crowns of the trees were badly burnt, while the bottoms were relatively less burnt. This makes sense to me. I would expect the heat and fire to rise upward. It would suck in cooler air, below, replenishing oxygen for the fire, while pushing the smoke and flames upward. It also seems like the tree tops would make more easily ignited fuel than the trees’ thicker, lower trunks.
But that can’t be the full explanation. The fire didn’t burn the tops of the trees away to nothing. The cross section of the tops of many of these trees can be seen, and they are not burnt all the way through.
So, the second part of my guess is that the burnt areas at the tops of the trees were severely weakened, which lead to eventual destruction from other environmental causes. Perhaps the burnt tops cracked where they met they unburnt bottoms, from the heat differential, from warping, expansion, and shrinkage. The burnt areas on the tops would also surely be full of smaller cracks, which would then perhaps be unevenly weathered by snow and ice expanding the cracks. These cracks would also open them up to faster destruction from fungi, insects, and various wood parasites. The burnt areas would surely be more brittle; perhaps they could no longer bear heavy Winter snow loads, or fierce Winter winds. Perhaps it was one of these environmental factors, or perhaps a combination of them.
So, my guesses are that the tops of the trees burnt more than the bottoms, and this weakened the tree tops, bringing them to eventual environmental destruction.
But, again: That’s just a wild guess. Do you have a guess?
If anyone actually knows the answers to these mysteries, I’d love to hear them.
Or, if you simply want to share your hypotheses, I’d love to hear those, too.
Come, share your guesses in the comment section.
For me, finding mysteries in nature, and pondering their explanations, is both a pleasure and a means to deeper understanding and appreciation. This, in turn, also leads to better pictures.
I hope you’ve enjoyed these mysteries, too. I wish you many natural mystery discoveries.
Frozen Puddle, Tuolumne Meadows, Yosemite National Park, California
Headless Trees, Rainbow Falls, Eastern Sierras, California
All pictures and text are © Mike Spinak, unless otherwise noted. All pictures shown are available for purchase as fine art prints, and are available for licensed stock use. Telephone: (831) 325-6917.