Sunday, April 03, 2011

Botany and the Indian Gulch Fire

First the Fire
(Photo courtesy Chuck Haraway)

As of Friday night at 6:40 p.m., March 25, 2011, "The Indian Gulch Fire is 100 percent contained after burning 1570 acres." Just that morning, 9 a.m., the fire map showed 1502 acres burned. In a great use of technology, the Jeffco Sheriff's Department kept a blog, regularly updated from the front lines.

I haven't seen a final map, but I'm guessing the fire captured the westernmost gulch, shown on this 3/25 map as an uncontrolled fireline, accounting for the 68 acres added to the tally on Friday. Here's my version of the official map overlain on topo; boundaries are approximate.

Also that Friday morning, Incident Commander Muir diverted some air resources from the Indian Gulch Fire to support firefighting efforts in Douglas County, Colorado, where the Franktown Fire (aka, Burning Tree Fire), also partly a grassland fire, burned 1,600 acres in little more than 24 hours before it was contained. On the 21st, firefighters briefly battled and conquered a third fire near Evergreen. A busy week!

In all, firefighters from 65 agencies responded to the Indian Gulch fire. They came from all over Colorado, plus Arizona, Idaho, South Dakota, North Dakota, and Florida(??!). The Jeffco Sheriff's Department reported that "fire crews have enjoyed a wave of support. Citizens have dropped off food, beverages, personal hygiene items, socks, and other supplies, all of which have been put to good use. Local businesses have offered free food and coffee to the firefighters between shifts."

Because I captured no photographs, please drop in on another local blogger, at Fun with Gravity, for great photos of this epic ecological event. Mtnrunner2 kindly gave me permission to use this dramatic photo. (Reminds me of Mordor.)

Local Ecology and Botany

Funny, we were just talking about Big Bluestem a week ago, and many of those south- and east-facing slopes I mentioned then were in the line of fire, so to speak. You can see the orangey bluestem just below the burned area in this photo, taken several days later. The dark shrubs below the line are unburned, but it's hard to distinguish burned area from dormant shrublands at this distance. That ashy white color above reveals the charred area a bit better.

You didn't hear much in the press about it, but Indian Gulch seems to have been predominantly a grassland fire, not so much a forest fire. Given the winds we had, that's a good thing! No doubt the firefighters struggled through some shrub-choked thickets in the gulches as well, but part of what burned had to be bluestem.

Also well in the line of fire, as revealed in the "no structures threatened" reports, is public open space parkland (Mt. Galbraith Park, at the east end, shown in gray here); more is private undeveloped land (Goltra property to the west). That's the good news.

Indian Gulch is also an area of significant botanical and ecological interest. That was, in fact, part of the reason the area was acquired as Open Space in the first place. Listed as a "Conservation Area" in a 1993 report by the Colorado Natural Heritage Program, the Indian Gulch area contains an occurrence of the rare Ute ladies' tresses orchid, Spiranthes diluvialis, identified in 1984 (from herbarium specimens) as a distinct species from the more robust Spiranthes romanzoffiana. [HT to the Chemist for botanical support on this one; Spidil and I are not well acquainted. He kindly provided this photo as well.] The area contains one of 10 original populations (8 of which are extant) in Colorado, and the only one in our county. Populations in Colorado and Utah accounted for 84% of the known individuals of Spiranthes diluvialis when surveyed in 2004.

Can't help wondering whether any orchids burned, and how tolerant they may be. As a species of wet/riparian grasslands, Spiranthes has probably been through this before.

In the End

All expectations are now raised for an incredibly busy fire season this year. (The newer Crystal Fire in Larimer Co. has already burned 4,500 acres.) The little graupely-sleet falling as I write this probably won't amount to much relief. We need a good upslope, dumping a couple feet of snow! (Nice view of red fire retardant on the hillsides, and charred areas to the right, in this last photo by Chuck Haraway.)

Thankfully, no lives, livestock, or homes were lost. Both the Indian Gulch and Franktown fires are believed to be caused by human action. Investigations continue.


Anonymous said...

Hi Sallie -- does this species flower in late summer like many other Spiranthes? If so, I doubt this early spring fire would have any impacts impacts. In fact, I suspect periodic burns are an integral part of the area's ecology and, over the long term, are beneficial to the orchid.

Sally said...

Agreed, Ted, and thanks for the comment! That's a very likely possibility, as the entire area has a longstanding relationship with fire and the Spiranthes does flower in late summer.