Have you ever sat under a grandmother tree? A grandmother tree is a large, ancient, and significant tree, and you’ll know one when you see it. There’s a grandmother cottonwood tree along the middle stretch of the Tanque Verde Creek, watching over a remnant cottonwood-willow riparian forest in the Tucson area.
Reaching an age of 70-100 years old, this grandmother cottonwood has seen many changes to the creek, from dropping groundwater levels and less flow, to new development, the shrinking of the forest, and very few grandchildren.
If you’ve walked along the creeks and rivers in the Tucson area, and much of the West, you might notice there are not many young trees. Cottonwood and willow tree populations are shrinking and young trees are rarely sprouting as groundwater pumping has dried up seasonal and annual creek flows, and the young roots can’t reach deep enough to tap into the lower water table. Land management practices have also hurt these forests, with development encroaching onto floodplains and intensive cow grazing eating young plants.
And yet, if you take a stroll along the middle stretch of the Tanque Verde Creek today, you’ll be delighted to see numerous young cottonwoods and willows popping up, many all on their own!
This area that is being restored we affectionately call the Tanque Verde Bosque–and this bosque, or forest, can once again be a multi-generational forest, expanding its extent and number of trees.
Hundreds of volunteers have been working with WMG to restore this creek, monitoring flows and groundwater, implementing water harvesting and recharge projects, and removing massive stands of Arundo donax, an invasive plant that has been sucking up a lot of water and choking out native plants for decades.
Sometimes river restoration work is about setting the right conditions for nature to succeed.
We’re seeing that once the Arundo is removed, the space and water that was monopolized by this invasive species is now available to new cottonwood and willow seedlings. River Run Network volunteers have cleared invasive Arundo from more than 66 acres over the last few years. And in 2023 and 2024, good rains and snowmelt led to many days of surface flow that’s needed for riparian trees to sprout.
Seeing the young cottonwoods and willows grow along the middle Tanque Verde Creek is a story we are so humbled to tell. We trust that the grandmother cottonwood tree will continue to share her wisdom and that this expanded forest will bring joy to us all.