October 26, 2016
Squatting next to my soil respiration collar, I had a moment to reflect. The ground around me was dark and charred. Small rocks littered the landscape, freshly broken from the intense heat. My computer logged carbon dioxide concentrations as I stood up to stretch my sore back. Around me plenty of trees still stood but none were living. They too were black and charred. Many more lay partially burned on the ground while deep holes in the earth showed where trees once stood but had been completely combusted, roots and all. In the distance a few pines swayed in the wind with massive green canopies that were spared by the heterogeneity of wildfire.
Nine months earlier this forest, known as the “Lost Pines”, burned in its second major wildfire in the last five years. It’s a very stark landscape, but beautiful as well, and it has been a unique experience to watch it change since the most recent fire. I have visited the burn every month since, at first just observing, then contemplating, and eventually coming up with a way to study it. There’s been surprisingly little research done on the effects of wildfire on soil ecosystems, especially in climates like Texas. I suppose most fire researchers are interested in the impact on the trees, but if the soils have been fundamentally changed, then there’s no way the plant ecosystem is going to regenerate.
Both fires here were classic “fire suppression” fires; they were caused by a buildup of fuels due to decades or centuries-long fire suppression efforts by locals. For many years, prevention under all circumstances was the prevailing wisdom when it came to fires, but the thinking is starting to change. More and more managers are letting fires burn or at the very least performing regular prescribed fires to remove the fuel build up. This is important because these ecosystems are actually adapted to fires; regular, low-intensity fires have always burned through the oak-pine forests of east-central Texas, removing dead wood and burning saplings to create the savannas that naturally grow there. Due to fire suppression, the forest grew too densely and burned spectacularly.
Forests have a kind of delicate balance that can continue for thousands of years undisturbed, but once an outside force acts on them big changes can occur. Fire suppression was one outside force that impacted this forest, the Bastrop Complex Fire of 2011 was another, a reaction to suppression. Which brings up two pretty fundamental questions for this place: will this ecosystem ever be able to return to its previous state and why or why not?
My computer continued to tick away, collecting the carbon dioxide measurements I use as an indication of biological activity in the soil which, coupled with chemistry and moisture data, I’ll use to answer these questions. The look of the soil has already told me a lot about my first question though. There is much less organic matter where the forest was burned, which means there will be less nutrients for anything living here and the community will have to shift. The forest lover in me is sad about that; this was a beautiful pine forest before the fire and, as the westernmost stand of loblolly pines in the country (hence “Lost”), it’s unique. But each time I pack up to leave, I’m excited. I visit this place once a month to study the system and the scientist in me just wants to look at all the data to see what is happening. Which is the great thing about studying the natural world: once I take a step back from my opinions and view something without the weight of my own history on it, it’s easy to (and in fact almost impossible not to) find appreciation and awe in every new thing I learn.