Hello Everybody!
If you’ve been paying attention to the news from the western part of the country in recent months, then you’ve probably heard about fire. Yep, there’s been lots of it. Washington, Montana, California, all over the place. Thankfully, for people anyway, fire activity here in the eastern Sierra’s has slowed of late, as we’ve received some rain and snow.
The Bishop Field Office, where I work, has had only a couple of fairly small fires near our border this year, but fire elsewhere has dramatically affected us. The Rough Fire started on July 31st on the western side of the Sierra’s, in and around Sequoia and King’s Canyon National Parks. We caught a lot of the smoke from that fire as it drifted east over the mountains and then settled down into the Owens Valley, and it put quite the damper on the late summer. 13,000-foot mountains are just 10 miles away from Bishop, but on many days we weren’t able to see them at all. And occasional days of snowing ashes aren’t much fun either. Cooler weather and rain finally knocked this 150,000-acre fire back a few weeks ago. Wildfires like that one may be a danger and an annoyance, but they are an inevitable, and even necessary, part of life out here.
Most of my workdays in recent months have revolved around fire, but I’ve been focused on past fires instead of active ones. My co-intern, Tyler, and I have spent much of our time visiting the sites of old fires, and recording data about their condition as part of an ongoing monitoring project. Most of the data we collect measures different traits about the presence, abundance, and size of different plant species that show up at these burned sites. Some sites that we’ve visited burned all the way back in the 1950’s, and others burned as recently as 2 years ago. What makes the project so important, and interesting for us, is that different sites will react to fire in dramatically variable ways. The data we collect is meant to help managers determine what causes these sites to respond differently to fire, and to track how sites change through time in the years following a fire.
Fire ecology is fascinating. We spend most of our time working in lands that fall in the western portion of the Great Basin Desert, and this is an area that has adapted to burn. The estimates I’ve heard vary quite a bit, but suggest that local shrub communities would probably have burned every 50-200 years historically. Lighting would have caused some of those fires, and others would be the result of intentional burning by native people. There seems to be plenty of disagreement about just how much fire activity we can attribute to Native Americans, but it could be a whole lot. Whatever their cause, fires here were common, and the plants have adapted to deal with them.
Most of the Great Basin plant communities we work with are dominated by woody shrubs (especially bitterbrush and big sagebrush) and perennial bunchgrasses (Indian ricegrass, western needlegrass, needle-and-thread grass, and Great Basin wild rye). When one of these shrublands burns, the woody shrubs are killed, but the deep-rooted grasses may survive, and are able to resprout and come back quickly after fire. Other species that disperse and establish quickly in recently burned areas move in as well. Yellow and rubber rabbitbrush, both woody shrubs with bright yellow flowers, are good examples of species that show up soon after fire. The previously dominant sagebrush and bitterbrush will repopulate the area eventually, but they grow and disperse more slowly. So, after an area burns, the plant community growing there will change over time, with different species exchanging dominance. When small to medium-sized fires burn intermittently across a landscape, as they typically would have a couple hundred years ago, the result is a mosaic of plant communities of different ages, and with different associations of plant species. That sort of variety is good for biodiversity, and good for the resiliency and “health” of the landscape.
Unfortunately, that natural process of fire and ecosystem response has changed quite a bit in the last 150 years as this area has become more densely settled and managed by not-so-native American settlers. We don’t seem to like fire very much, and have tried to suppress and put out wildfires ever since we got here. That’s perfectly understandable, as fires are dangerous and destroy most of what gets in their way, but the problem is that suppressing fire has allowed woody plants and plant litter to build up, when it would usually be burning off more regularly. So, when fires burn now, there is more fuel available to them, and they burn hotter, faster, and bigger than they did in the past. That makes them more dangerous for us, and the more severe fires may sometimes be too destructive for the fire-adapted plant communities here, so that burned areas aren’t able to recover as well. Invasive species, especially cheatgrass, are also part of the problem, as they burn easily but also move in quickly to dominate areas that have recently burned.
How do deal with and manage wildfires is a complicated issue, and I won’t claim to know what is the right way for us to go about it. But hopefully the data I’ve been collecting about burned areas will become helpful information about how natural areas here are responding to fire.
Until Next Time,
Steve Tillman
Bishop BLM Office