The Truckee River sparkles under a bright, clear sky. In the mid-morning heat, more than 40 volunteers with One Truckee River gathered to plant Valley Oak, Wood’s Rose bushes, Jeffery Pine saplings, and other native species at Fisherman’s Park.
But there’s one tree that stands out from the rest. Cottonwood trees are a keystone species — the glue that holds together an ecosystem. Their dancing branches and heart shaped leaves provide shelter for birds, food for insects, and escape from the summer heat. Without them, the Truckee River would look very different.
Tara Tran, technical support lead with the One Truckee River Workforce Program, said downtown once thrived with lush cottonwood forests. But decades of diverting water for irrigation and a growing population, reshaped the river. Economic development and straightening the river affected how it flows and floods today, presenting challenges for cottonwoods and other native species.
“Naturally, on the banks of the river, you would see hundreds and hundreds of fields of cottonwood seedlings, but since we do that channelized river and that reduced floodplain, it is a lot more difficult,” said Tran.
On the surface, the river looks normal, with its white rapids flowing into cool, shimmering water. But low snowpack, invasive species, and water stress are also growing issues for cottonwoods.
A gentle breeze passes through the heart-shaped leaves of tall cottonwood trees as they glitter in the mid-morning sun. Each spring, they release thousands of tiny, fluffy seedlings that float and settle on the sandy banks of Oxbow Nature Study Area.
Noelle Patterson, a hydrologist at Utah State University, studies Nevada cottonwoods using dendrochronology. She said cottonwoods live fast and die young, but their growth rings show a lifetime of changing water availability.
“This was a rough spring, it was really sad to see, really scary, the snowpack was just decimated by these temperatures,” she said. “Flows are going to drop across rivers and streams throughout the watershed and it's going to be extra strain on all users of water, including the environment.”
Snowmelt in spring is crucial for the whole river ecosystem, from native Cui-ui suckerfish to cottonwood saplings. Patterson said faster snow melts and warmer winter storms leave them vulnerable.
As the river overflows with small, regular floods, it brings high currents and cool water that is stored underground. Cottonwood seedlings need access to this groundwater right away.
Most of the time, the fluffy seeds need Goldilocks conditions — not so close to the water that they get swept away, but just close enough for them to establish their roots.
“Cottonwoods like to have wet feet,” said Patterson. “These new little trees are kind of in a race to keep up with that dropping groundwater table.”
While some areas of the river are racing to keep up with a changing climate, downstream, McCarran Ranch Preserve is showing slow and steady recovery.
With the hum of the highway and warehouses nearby, McCarran Ranch’s tree-lined trailhead stretches for miles. It’s thriving with a forest of fluttering cottonwoods, native grasses, and wispy willows.
Christoffer Sega, stewardship manager with the Nature Conservancy, said this area of the river represents decades of restoration work. Before the conservancy bought the property in 2001, a previous flood control project wiped out 90% of the river ecosystem and more than half of bird species.
“There weren’t any trees,” he said. “This was an abandoned alfalfa field, and it was just weeds, and it was flat, there were no cottonwood trees, no grass, no birds, nothing.”
Sega said it’s important to learn about the history of the river, and the ongoing efforts of Indigenous communities downstream. He’s hopeful that more community-led restoration efforts will continue to balance the needs of people and wildlife.
“You can actually see that change happening in our lifetime. A lot of good stuff is happening, but we really need to be careful stewards of the environment, because everything is built on it,” he said.
There are a number of groups working to protect the Truckee Watershed, including River Justice, an Indigenous-led river clean up project, Keep Truckee Meadows Beautiful (KTMB) and One Truckee River.
Whether you’re participating in a river clean up, planting, monitoring, or restoration work, learning about native species helps work towards maintaining a healthy river ecosystem.