by Karl Wirsing/SEFS
In 1988, wildfires burned about a third of Yellowstone National Park’s forests. Most of those wooded areas hadn’t burned in 100 to 300 years, largely within the average burn cycle for those forests, and they bounced back really well from the disturbance. But what happens when the next fire comes far sooner than the average? With shorter-interval burns and changing climate conditions, will the younger trees and forest be as resilient to a severe fire? Along with collaborators at the University of Wisconsin, Professor Brian Harvey will try to answer those questions, among others, this summer as part of a new National Science Foundation grant for Rapid Response Research (RAPID).
A lodgepole forest in Yellowstone that naturally reseeded after the 1988 fires.
RAPID grants are a special category for funding research that needs to be carried out immediately. They provide a one-year pulse of money for time-critical projects that can’t wait for the usual funding cycle. In this case, more than 10 thousand hectares of forest in Yellowstone did in fact re-burn last summer—only 28 years after the 1988 fires—so this summer will be the first and best opportunity to observe how these forests respond to the short-interval disturbance. “This grant provides an awesome opportunity to get there as soon as the forest is likely to show signs of resilience, or if it is not going to be as resilient,” says Brian. “This is the key time and place to be testing these questions.”
Natural disturbances, of course, are integral to forests worldwide, but conifer forests in western North America are facing warmer temperatures and larger, more severe wildfires than at any time in recorded history. Changing climates—with hotter, drier summers—are increasing disturbance frequency in some areas, and disrupting long-established patterns of forest regrowth and succession. In Yellowstone’s forests, the dominant species is lodgepole pine, which has closed, serotinous cones that release their seeds only in response to fire. Nearly all of the seedlings then establish one year after a fire; historically, they’ve then had many decades to grow and start producing cones (and seeds) of their own before the next burn. But instead of a fire interval of 150 to 300 years, these Yellowstone forests could start seeing new fires within a matter of a few decades. “Some systems are used short-interval fires,” says Brian. “But throughout much of Yellowstone, that’s a novel thing.”
The ecological consequences of these changing fire regimes are unclear and could be profound in the next century. The results of this study, in turn, could be widely relevant for understanding abrupt changes in forest ecosystems across the globe.
“This project is a unique opportunity to test what’s going on at the leading edge of climate change and changing fire regimes in these areas,” says Brian. “We’re really seeing the start of conditions in Yellowstone that may be heading outside the range we’ve seen in the paleo-ecological record. No matter what we find, it’s going to be extremely exciting, and very important. On one hand, these ecosystems can always surprise us in their resilience. On the other hand, as many times as we’ve been surprised by their resilience, we may be heading toward a state where things could be changing pretty rapidly.”
Similar to the sites Brian will be studying this summer, this lodgepole pine forest—originally burned in the 1988 fire—was re-burned in 2012 (with this photo taken in 2015).
Starting this July, Brian will head out to the burned sites in Yellowstone with his incoming master’s student, Saba Saberi, along with an undergrad field intern. They will meet up with a team from the University of Wisconsin, and together they’ll be investigating and measuring a number of factors for how the shortened fire interval is affecting the forest, including burn severity, post-fire tree seedling establishment and carbon storage.
A major component of this research, which Brian’s master’s student will be leading, involves studying how well satellites can measure burn severity in forests that are still very young since the last severe fire. “We have well-developed satellite indices to measure burn severity in forests, but most of these indices have really only been tested on older forests with much greater live biomass,” says Brian. “However, when fire burns through a dense stand of 25-year-old trees, we don’t know how accurately the satellite can detect burn severity. This is a big part of what Saba will be testing in her master’s research at SEFS. “Calibrating these satellite indices will allow us to investigate spatial patterns of burn severity over much broader scales, and gain insight into how fire regimes may be changing right before our eyes.”
The RAPID grant provides a total of $200,000 in funding, with just under $60,000 coming to Brian for his role in the project, and the rest supporting his collaborators at the University of Wisconsin.
Also joining the crew in the field will be a freelance writer from the New York Times to spend a weekend a write a store about the project. The Discovery Channel will be sending a team, as well, as part of documentary about the research on climate change and fire. Brian and his collaborators plan to produce a series of mini-documentaries (5-8 minutes in length), in English and Spanish, to explain effects of increased fire activity and climate warming on western forests to a wide audience.
It’s going to be a packed July for Brian and his partners, and we look forward to hearing reports from the field!
Photos © Brian Harvey.