Friday Fractal XX

Deep within the pockets of a Mandelbrot set, delicate branches display endless variations. When highlighted with the colors of autumn, (since today is, after all, the Autumnal Equinox,) patterns of exquisite beauty emerge:

These patterns can remind us of many forms in nature, including a grove of quaking aspen:

Quaking Aspen (Populus tremuloides)

Aspen are members of the poplar family, along with their cousins, the cottonwoods (featured in last week's fractal.) While they are known for their brilliant foliage in the fall, the species has another claim to fame: the world's largest organism is an aspen clone. This sounds like some giant tree grown in a lab, but actually refers to a grove of aspen trees which share the same genetic markers, and are connected by vast underground root systems. One clonal colony in Utah covers 106 acres and is estimated to be over 13 million pounds and possibly millions of years old. Utah's giant clone, dubbed Pando is entirely male.

Colorado's high country is scattered with many aspen clones (although they tend to be somewhat smaller than Pando.) Every autumn, thousands of tourists take scenic drives along the winding switchbacks, hoping to catch a glimpse of Colorado's clones. Unfortunately, an article in this morning's Aspen Times suggested this autumn may not be as spectacular as most years:

Plenty of late-summer rain, combined with last weekend's freezing temperatures and snow, conspired to sap some aspen groves of their usual vibrant gold hue, and the return of winterlike conditions this week probably won't help.

That's not to say there aren't pockets of beauty in the high country, but this year's leaf-peeping season isn't measuring up to the luster of a typical autumn, locals have been quick to observe.

The article also briefly explained how the brilliant colors occur-or not, as the case may be:

The season's longer nights cause leaves to change from green to autumn's hues. Not all of the details are understood, but three factors affect the color: leaf pigments, longer nights and weather.

As the nights grow longer and the daylight shorter, biochemical processes in the leaf start the color-change process. Production of chlorophyll (a pigment that causes the leaf to be green and allows the plant to convert sunlight to food) slows down and eventually stops. As the chlorophyll is destroyed, other pigments are unmasked and show their colors. These pigments include carotenoids, which produce yellow, orange and brown colors in such things as carrots and daffodils, and anthocyanins, which give color to familiar foods like cranberries and plums.

Color brilliance is related to weather conditions that occur before and during the time the leaves' chlorophyll dwindles. Temperature and moisture are the main influences. (Source: U.S. Forest Service)

When I drove into Roosevelt National Forest yesterday, I was able to find a few of the colorful "pockets" mentioned above. It was definitely wet, however. While I was hiking along a trail near Rollins Pass, a light drizzle of rain began to fall. Shortly after I discovered a brilliantly colored grove of aspen, the rain turned into snow. It wasn't a storm, by any measure-the sun still shined through the clouds, lighting up the quaking aspen leaves:

Early snowflakes (the white spots scattered about the picture) fall on an aspen grove.

There was no doubt; the seasons were changing. (On a slightly tangential note, George H. Church and his son John drove cattle past this area over 100 years ago. I came to this area, in part because it is the quickest route into the high country from my house, but also to see the places I'd been writing about. I'd planned to title the next part in the series Seasons Change, thinking of the shift of focus from George to John, as well as a few classic stories about the Colorado snow. My moment of zen in the aspen grove made the title so much more appropriate. If only irony could always be this beautiful.)

Our look at the aspen, and other poplar trees may soon change as well. Last week, the first complete genomic sequence of a tree was unveiled-and what better tree could there be to map than a poplar? In order to understand more about the instructions for tree-making, scientists chose the black cottonwood, a relative of both the aspen and the cottonwood featured last week. The Boston Globe article described the discovery, and where it may lead us::

Besides being a useful research model for plant scientists, the hardy, fast-growing black cottonwood and other poplars are also important sources of fiber for paper and lumber. A genetic "roadmap" of how poplars form wood will help scientists harness this material to make liquid fuels such as ethanol, said coauthor Carl Douglas, professor of botany at the University of British Columbia. "We need to know how [wood] is made to know how to use it."

As the seasons turn and the climate changes, we learn more about these branching beauties, and the way they fit into our environment. Most importantly, we begin to realize there are more to these trees than meets the eye.

All images taken by the author; fractals made using ChaosPro.