With Laramie's trees now changing color, the debate is on. Some claim that chlorophyll, the compound that captures solar energy and also makes leaves green, is breaking down, thereby revealing other pigments—yellow and orange carotenoids. And if conditions are right, trees will manufacture additional pigments—red and purple anthocyanins—for purposes not understood. Perhaps it's an aesthetic choice.In these dreary demoralizing times, I cling to the tiny-artists hypothesis. Autumn leaves are painted by darting leaf fairies so small that we can't see them, no matter how hard we try. But we can easily appreciate their masterpieces. Toward that end, I headed off to LaBonte Park to find out what the leaf fairies had done to my chokecherry tree.
This particular tree is my tree-following subject this year, the idea being to visit and report on it each month (I've missed a few). I was curious about the leaves because it's a purple-leaf chokecherry. What color do purple leaves turn in autumn?
LaBonte Park has a nice show of trees currently—yellow and orange deciduous trees, and dark green conifers. 
The purple-leaf chokecherries haven't changed much. The leaves are more on the red side of purple, but nothing dramatic.
Have you noticed the "subdued" quality of these photos? I resisted the temptation to photo-enhance. This is what our world looks like much of the time. Actually, this was a relatively good day.
LaBonte Park yesterday afternoon, "unhealthy for sensitive groups".
St. Matthew's Cathedral in Laramie Oct. 5, "very unhealthy". Laramie Boomerang.
On September 17, in the Mullen Creek drainage on the west side of the Medicine Bow Mountains, a spark still being investigated set the forest ablaze. These mountains are thick with standing dead trees, "victims" of pine bark beetles. In many areas, half to three-quarters of the trees are dead. With all this dry fuel and very strong winds, the Mullen Fire raced eastward, consuming 175,00 acres (71,000 hectares) as of this morning.
Mullen Fire, just one of many in the western US (InciWeb, Oct. 11).
Thirty miles south of the Mullen Fire, the Cameron Peak Fire is also burning beetle-killed trees and generating lots of smoke (InciWeb, October 11)).
Fortunately, thirty miles of prairie lie between Laramie and the mountains—grassland where fire can be quickly extinguished. But the smoke will be with us for awhile. Wildfires typically create a mosaic of burned and unburned areas within the overall perimeter. Unburned patches will continue to ignite, producing large amounts of smoke until enough snow falls and stays.
Smoke and airtanker, Mullen Fire. From every news outlet in the region; original source unknown.
Next spring, it will be fascinating to investigate the mosaic of live and dead trees created by the fire ... perhaps a subject for 2021 tree following :)
For more news, visit our monthly gathering of tree-followers kindly hosted by The Squirrelbasket. Want to join in the fun? More here.
