Wednesday, April 22, 2015

After the fires in New Mexico

Valles Caldera Grande, Jemez Mountains, NM
I've been traveling a lot for work lately, and last week I was in Santa Fe NM. I was there to attend a conference on native seeds. The day before the presentations started I was able to attend a field trip touring recovering wildfire sites in the Jemez Mountains, near Bandelier National Monument. Most of the sites we visited had burned twice, once in 2008 (I think), and again in 2011.

wild candytuft (?) in the caldera
We visited the Valles Grande in the Valles Caldera, an active volcano complex 13.7 miles across altogether. This caldera last erupted approximately 1 million years ago. We were given half an hour to explore it, and most of us made a bee-line to the meandering creek dividing the center of the caldera. The problem is it appears deceptively close. I'd guess the Valles Grande is ~3 miles across where we parked. Not one of us made it to the creek by the halfway point, and we were called back short of our goal. Oh well. At least we got to tromp around this montane clearing.

What I didn't understand is this: why no trees? Ponderosa pine and aspen grew at elevations both above and below the caldera, so why not in the caldera itself? Is the ground too saturated with water? The caldera supported a luxurious grass thatch, even with the recent wildfires and historic grazing. Candytuft and marsh marigold (questionable IDs) were the only non-grass plants active at this point in the season.

We could see an abundance of human activity despite the remoteness of the location. The Valles Grande has a (now defunct) ranch within it, and shards of flaked obsidian near the overlooks marked the points where native peoples had sat and worked the stone long ago. The presence of the obsidian shards on the soil surface is a testament to the relative remoteness of the locations we toured. Surely more travelled trails would have had these remains pocketed years ago. It is also possible that the tremendous fires of the past ten years have exposed these remains at the surface.

Unmolested flint knappings at the soil surface
I know that in the tropical rain forests, the first fire marks the beginning of disturbance, but it is the second fire that destroys the ecosystem. This area suffered the same fate. Trees that survived the earlier fire were killed 5 years later when the second fire came through and burned the underbrush and deadwood. Apparently, the smokejumper team from Prescott Arizona that perished in 2013's Yarnell Hill Fire cut their teeth on the 2011 fires in the Jemez.

Compare the brown areas to the green
With this is mind, it was easy to lose myself re-enacting fire behavior in the mountains from the fire scars and standing trees. At its peak it advanced an acre a second. You could see where some (very few) pines had been spared, but you could also see white scars on the earth where the fire had burned so hot the soil had been mineralized, still visible 4 years later. Would my instincts have led me into a trap? I'll never know.

Mineralized soil and dead trees, 4 yrs later

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