An icon for scientists studying the history of New Mexico’s climate, Yoda survived many a drought. But the tree couldn’t get through the latest one, said University of Tennessee professor Henri Grissino-Mayer.
Yoda was alive in March, according to Grant Harley of the University of Mississippi, one of a posse of researchers who have been tracking the tree. But when Harley brought a group of students to the remote site in August, the tree was dead.
“Bummer,” Harley wrote in an email sharing the news. “We had a moment of silence to pay our respects.”
Grissino-Mayer was a graduate student in 1991 when he and a colleague found Yoda among a stand of Douglas fir trees growing out of a lava flow at El Malpais National Monument south of Grants. Douglas firs can grow 150 feet tall or more. Yoda was maybe 7 feet tall. But when Grissino-Mayer carefully removed a pencil-thin core of wood (this doesn’t harm the trees) to count Yoda’s annual growth rings, he found that the tree had been alive since at least 1406.
Gnarled, with a head of dead branches and a few live ones springing from his crown, Yoda looked every bit the wise elder. “Size,” as the tree’s Star Wars namesake said, “matters not.”
“He became kind of our spokes-tree out there,” Grissino-Mayer recalled when I phoned him last week to reminisce about the life and times of Yoda the Douglas fir.
The wisdom found in Yoda’s rings, and the rings of the other trees of the Malpais, has been crucial to our understanding of the history of New Mexico’s climate.
Under the right circumstances, trees like the Douglas fir of the Malpais put on wider growth rings during wet years, and thinner ones during dry years. By counting back the years, and measuring many trees, Grissino-Mayer and other tree ring scientists have assembled a chronology of New Mexico’s droughts and wet spells. It tells us far more than we would know simply by looking at the records kept in the past few hundred years that measurements have been taken.
Yoda and the other Douglas firs of the Malpais are especially useful, Grissino-Mayer said, because their remote and rugged location means they’ve been largely unmolested by the press of humanity that makes many forests hard for the tree ring scientists to work in. If you’ve ever tried to walk across the lava flow, you’ll understand why logging and ranching have had no impact on Yoda.
One of the things Yoda and company have told us is that New Mexico has been subject to droughts far longer than we have experienced in the modern era. Among the worst was a period in which Yoda and the other trees show thin rings and therefore dry weather for half a century beginning in the mid-1500s, including an awful 25-year stretch from 1575 to 1600, according to Grissino-Mayer.
“Yoda lived through it,” Grissino-Mayer said.
By the numbers, the current drought does not approach the great megadrought of the 16th century. It’s been going on for 15 years. Twelve of the past 15 years have been drier than the long-term average in New Mexico, and 13 of them have been warmer than average.
But comparisons are complicated by the fact that, although the current drought has been shorter, the warm weather has been particularly tough on trees, according to research by former Los Alamos National Laboratory scientist Park Williams. A new study by the U.S. Forest Service’s Rocky Mountain Research Station noted “increasing mortality and declining growth” in the state’s forests in the past decade.
Grissino-Mayer is cautious about comparisons between the current situation and the megadrought of Yoda’s youth. Fifteen years is not enough, he said, to draw conclusions. “We can’t really say yet that this is a worse drought, because I don’t think this drought has ended,” he said.
Grissino-Mayer plans to return to New Mexico in the next year to study what’s happening, including gathering data on how many of Yoda’s aging kin also have perished in the current drought.
In the meantime, Harley found a cone at Yoda’s feet, and plans are underway to try to grow new trees from the seed.
“Hopefully,” Harley said, “there will be Yoda descendants.”