A light snowpack in the northern mountains led to a dry 2025 for the bosque of the Middle Rio Grande Valley. The river ran dry for long stretches, and a flourish of monsoon rains toward summer’s end only provided a modest measure of relief. The cottonwoods that define and dominate the riparian forest in Albuquerque have been thirsty, as evidenced by a few patches of yellow, and more than the usual amount of fallen branches.
Rio Grande Nature Center State Park Superintendent Levi Dean and his staff have been stewarding their stretch of the bosque through the dry year.
“It’s one of the largest continuous stands of cottonwoods in the world,” Dean said. Most of the forest’s cottonwoods, including the tallest ones, can trace their origin to 1941. That year, New Mexico received more than 27 inches of rain, according to the National Weather Service. That total, more than twice the long-term average, remains the wettest year on record. Albuquerque flooded twice in 1941 - once in May, and then a historic flood in September. The flood generated a prolific cohort of cottonwoods.
Since then, the trees close to the river have mostly flourished, drinking from groundwater when surface water didn’t provide enough. Further from the river, the water table sinks a bit, making it more hit-or-miss for cottonwoods, which do best in valleys that flood seasonally. Now that the Rio Grande has been channelled and dammed, the floods are infrequent.
“So with trees that are old and kind of aging out, and drought stressed, and we’re starting to see a lot of limb fall and disease and things in the trees,” Dean said. Cottonwoods typically live 80 to 100 years, Dean said, so the 1941 cottonwoods would be nearing the end of their life cycle, in any case.
The current drought has not caused a catastrophic loss of cottonwoods, but there has been a culling, as some elderly trees that began the year in weak condition did not make it through the summer. However, as happens so often in nature, death can nourish life.
“Honeybees actually love rotting cottonwoods,” said park manager and law enforcement officer Dylan Frentzel. “So there are a lot of hives in the cottonwoods, and you have to be careful cutting trees, because a lot of them are hollow. Raccoons will live in the tree. And woodpeckers absolutely love it, too.”
Rio Grande Nature Center State Park staff are doing their best to help new cottonwoods replace the old ones. Volunteer baby seedlings are potted, then planted once they get big enough.
“We are aggressively trying to germinate new generations of cottonwoods,” Dean said. Young cottonwood saplings dot the forest floor near the Nature Center’s buildings. Some are faring well, while others show signs of drought stress.
In a couple of decades, regardless of how the climate treats the bosque, almost all of those 1941 cottonwoods will be gone. Those who grew up in Albuquerque enjoying the majestic trees might find it hard to imagine the bosque without them. However, some cottonwoods that are young now will likely grow to a stately height. If they do, they’ll be part of a bosque that isn’t quite as cottonwood-dominated as the one we have now.
That more diverse forest in the years ahead might in some ways resemble the bosque of the past, before the river was channelled. The Rio Grande before development meandered through a highly varied flood plain, sandy in some spots, muddy in others. Ox-bow lakes and vernal pools hosted a variety of flora and fauna.
That exact same ecosystem isn’t likely to return, but a variety of young trees are already starting to claim the mantle passed on to them by the cottonwoods of the last century.
“One thing we’re seeing is that junipers are starting to pop up,” Frentzel said.
If the climate gets warmer, as expected, the bosque could be populated increasingly by trees that can handle the heat.
“So the bosque of the future, we’ll see juniper and other trees, like screw beam mesquite, that may be better suited to hotter, drier climates,” Dean said.
Even the Siberian Elm, an invasive species not universally beloved in New Mexico, could play a helpful part.
“In times of drought, they’ll actually pull water from those higher soil profiles up to the water table, and it’s beneficial for the willows and the other trees,“ Frentzel said.
The netleaf hackberry and Mexican elderberry, both native, also handle dry summers better than cottonwoods.
“They’re very drought tolerant,” Frentzel said of the netleaf hackberry. “They also thrive in riparian ecosystems.”
“Our Mexican elderberries, they’ll go to about 25 feet, and they grow rapidly,” Dean said.
The cottonwoods of 1941 will be mourned and missed when they’re gone. But even with climate change and the prospect of many hard summers ahead, Dean said the bosque itself will endure.
“There’s resilience in this ecosystem,” Dean said. “In the future, we will have stands of cottonwood. It’s just that it may shift, and we’ll have more of a mosaic, though a different mosaic than we had before dams and diversions. We just have to do the best we can and fight for these trees in the future.”
