Amateur Naturalist: Cerro Grande Peak: Scene 5 – The Fields Of Boulders

Trees on the upper side of the felsenmeer were not burnt in the Las Conchas Fire in 2011. Flames did not pass from below over the top of the boulder field, protecting the trees. Areal image by Google Earth Pro
A pika gathers plants to store for the winter. Photo by Ann Schonlau/National Park Service
Amateur Naturalist
Los Alamos
We have been reviewing the play called “Hike to the Top”. It has five scenes that involve the ascent of Cerro Grande peak. The fifth and final scene of this play is the felsenmeer toward the top of the peak. The views are dramatic as the trail reaches to the top. The felsenmeer however is a quiet but heroic player for the trees and pika that are in this final part of the play. The felsenmeer is heroic because it is a large bolder field that can block a forest fire. There is a felsenmeer that is a short distance from the trail on the way to the top. Conifer trees are growing between the felsenmeer and the meadowland. This is in contrast to the burnt tree trunks on the other side of the felsenmeer further down the western slope of the Cerro Grande.
The Las Conchas forest fire is the villain in this play. It had been burning upslope toward the meadowland when it encountered the felsenmeer. The felsenmeer did not have plants growing on it to be fuel for the fire. It also was too wide for flames and embers to fly across. The trees on the upwind side were saved.
Pika are the icons of the high country. They are busy little mammals throughout the summer collecting plants to store by their homes. Stacks of drying plants can be seen by the entrances to their homes. Their homes are under the rocks of a felsenmeer. Their charming squeaks warn other pika when danger is present. The rocks of a felsenmeer remain cool into the summer, something to which pika are adapted. A home under a rock field is a good protection from a forest fire.
Although safe from forest fires by living in rock fields, pika are threatened by something more subtle: climate change. Pika are very sensitive to temperature. They go into their burrows on even mildly warm days. Pika may move to even higher and cooler elevations in coming decades if rock fields are available. They will be an indicator of a warming climate based on their behavior. They also may become extinct except at very high elevations. The Sangre de Cristo Mountains to the east are higher than Cerro Grande peak and the other peaks of the Valles Caldera. But how can a pika cross the Rio Grande Valley to reach the Sangre de Cristo Mountains?  
Alternatively will there be enough time so their physiology can adapt to a warmer climate from generation to generation?
Trees growing on the upper side of the felsenmeer in 2017 now stand in contrast to the burnt ones on the lower side. Aspen trees are growing on the right side as the first new growth. Areal image by Google Earth Pro
The forest fire moved from the right to the left. The felsenmeer blocked the fire from reaching the trees on the left. Photo by Robert Dryja
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