Drought and heatwaves affect more than just humans, which is the case this summer as the Roaring Fork Watershed continues to experience “exceptional” drought — the most severe rating per the United States Drought Monitor. Human residents can see visible stress in local plant life as well as animals.
To learn more about drought stress on trees and local flora, The Sopris Sun reached out to Roaring Fork Conservancy (RFC) Water Quality Technician Matthew Anderson and Carbondale Town Arborist Carl Meinecke.
“The effect of drought and low flows on plant life depends on the plant type, age and proximity to the river,” Anderson said. “Some will tolerate one dry year, but are impacted by prolonged drought.”
Riparian plants, especially native ones, struggle less than upland plants given proximity water, he said.
“The further plants are from the river,” he continued, “the more likely they are impacted by drought. Plant life closer to the river might show significant stress only after multiple drought years.”
Anderson said that RFC pays close attention to plant life at the headwaters of Roaring Fork tributaries. If those areas are drier than average, that doesn’t bode well for downstream ecosystems.
“Vegetation health in upland headwaters areas are particularly valuable in any watershed, because these forested lands host the snowpack and filter water as it moves across the land,” he said. “When the vegetation is dry in these headwater areas, poor plant health and increased fire potential are of particular concern.”
Anderson encouraged caution and preventative action to help protect these ecosystems. “Leave riparian vegetation intact,” he said. “It provides shade, filtration and stability to rivers.”
As far as helping the trees along the river banks, he said that folks should “reduce outdoor watering and make sure sprinkler systems are watering the lawn, not the sidewalk.” He added that, “Water used to grow lawns is water from the river,” and that, “During significant drought, only water your lawn once per week.”
Carbondale canopy
Town Arborist Carl Meinecke offered recommendations on how people can identify and respond to stress symptoms of thirsty trees.
“Signs of drought-related stress on broadleaf trees include leaf scorch, premature leaf drop, wilting and reduced leaf size,” he said. “On a conifer tree, look for needle browning, thinning in the canopy and reduced growth.”
“Once confirmed drought stress is the issue,” Meinecke continued, “consider if there have been any changes to the amount of water the tree usually receives. In general, trees like deep, infrequent watering.”
How much that water absorbs into the ground is important, he added.
“It’s important to observe how the tree responds, and adjust irrigation as needed,” he said. “It is possible to overwater a tree, and in that case it may show similar signs of stress.”
Young and recently planted or transplanted trees are more vulnerable, Meinecke said. “I recommend closely monitoring trees planted within the last three years. Water is one of the most important factors in a tree’s ability to become established.”
He explained that after a tree is transplanted, it is important to keep the root ball moist. Otherwise, the tree may not make it through the year.
“This year, I am going around and checking on younger trees that I have planted, and giv[ing] supplemental water if needed,” he said of the trees in Carbondale. “The key is to water at least within the trees canopy and a bit further if possible.”
He noted that in Carbondale, many of the public-right-of-way trees are alterations to the native ecosystem.
“In reality,” Meinecke said, “this area probably was sage brush with trees mostly along the river’s edge. It’s really impressive the number of trees over the past many years various residents, volunteers and town staff have gotten established that our community now benefits from.”
But he expects that some trees on both public and private property may not survive the summer. “I have two small ornamental lilac trees that will probably not make it through the summer,” he lamented, noting that recently planted lilacs are among the struggling species.
Multiple Carbondalians have reported stressed or dead trees around town, including in the City Market parking lot.
“The trees in the City Market parking lot are not maintained by the Town and are the responsibility of City Market,” Meinecke said. “However, it is not uncommon for a few trees to not become established even if everything goes as planned. It’s kind of like putting flowers in your garden. You plant 10, but one might not make it.”
Learn more about the Town of Carbondale’s trees at tinyurl.com/Carbondale-Trees, and/or Roaring Fork Conservancy at roaringfork.org/your-watershed