Study: NM woodlands could become barren
What would New Mexico’s high desert look like without piñon and juniper trees dotting the hillsides? According to a new scientific study, New Mexicans might come to live amid such a landscape, virtually barren of all coniferous trees, within a generation or two.
The study, led by a Los Alamos National Laboratory researcher, says the conifers of the southwestern United States’ pine-juniper woodlands could be wiped out by climate change. “What we found is that, by 2050, give or take multiple decades, there should be no forests in the Southwest,” said Los Alamos ecologist McDowell, lead author of a paper published Monday by an international team in the journal Nature Climate Change.
This study focused on the lower-altitude, more drought-tolerant piñon and juniper trees. Earlier LANL research at the lab produced similar, broader findings for forests including higher altitude trees like ponderosa pine and there are already “wipeouts” at higher elevations, McDowell said.
The paper says the survival mechanisms of Southwestern trees will accelerate their own demise if the long-term pattern of higher temperatures and drought continues. To prevent water loss, a coniferous tree closes the stomata — openings in the needles that take in gases. But closure also prevents the trees from taking in carbon dioxide, the tree’s food source, and stops photosynthesis, the process by which plants convert sunlight to fuel for life. And leaving more carbon dioxide in the air just makes the atmosphere warmer.
“So it’s like a thermostat gone bad — the warmer it gets, the more forest we lose, the forests are then not taking up CO2, so the warmer it gets,” McDowell says in a video interview provided by LANL. “So it feeds back on itself. This is the threat we are concerned about.” Carbon dioxide emissions make up most greenhouse gases that hold heat in the earth’s atmosphere.