Can Transplanted Willows Help Restore Critical Riparian Areas in the Waldo Canyon Burn Scar?

Can Transplanted Willows Help Restore Critical Riparian Areas in the Waldo Canyon Burn Scar?

March 10, 2016 by Jennifer

In January 2016, RMFI began a new pilot project in partnership with the U.S. Forest Service to investigate the role that mature rooted willows can play in helping to restore critical riparian areas within the Waldo Canyon burn scar. In the summer of 2012, the Waldo Canyon Fire burned over 18,000 acres west of Colorado Springs, impacting four major watersheds within the region. Since that time, a tremendous amount of work has been completed within the burn scar by a variety of different groups and entities aimed at stabilizing steep slopes, protecting watershed health, improving drainage, minimizing post-fire storm flows, and catalyzing native vegetation recovery. RMFI has been instrumental in providing hand crew project planning and field crew training and supervision.

As a result of the Waldo Canyon Fire, a substantial amount of riparian vegetation was lost, which has significantly impacted erosion rates and watershed health. Resultant sediment deposition has inundated unburned riparian vegetation within portions of Queens and William Canyons. This residual plant cover is an important component of the mosaic vegetation communities associated with spotted owl breeding habitat. The Waldo Canyon Fire also resulted in a reduction in the extent and suitability of Preble’s Meadow Jumping Mouse habitat within several drainages. In addition, increased peak flows and decreased flow resistance from destroyed riparian vegetation have resulted in an increase in the headward expansion of associated drainage networks.

Riparian areas provide critical ecosystem services. Riparian vegetation including grasses, forbs, and woody plants growing along the edges of ephemeral and perennial drainages is critical for controlling erosion, improving water quality, and providing habitat. Willows are among the most common woody plants found in riparian areas. They are an important source of food and cover for wildlife and their roots help stabilize streambanks, minimizing wind and water erosion.

Willows are commonly used in a number of recovery and resiliency initiatives including post-fire conditions. They can grow rapidly and provide effective soil stabilization along streambanks or in other highly erodible areas. Willows can sprout new shoots from roots and root crowns readily, and their stems possess abundant adventitious buds that have the flexibility to form roots when in contact with saturated soils.

Traditional use of willows in post-fire recovery efforts involves strategic harvesting of dormant willow stems from vigorous healthy willows. Dormant cuttings are then driven into the ground, where they sprout shoots and roots during the growing season. Once established, willow cuttings form a web of fibrous roots that can provide highly effectively soil stabilization. This method is advantageous in that it is quick and relatively easy to accomplish, however, survival rates of cuttings can vary dramatically depending upon environmental conditions. Low survival rates of stakes are often observed in areas where the water table fluctuates resulting in poor soil moisture during the growing period. Monitoring of willow transplants in the Hayman and Waldo Canyon burn scars has revealed an estimated 10% survival rate.

RMFI’s new project seeks to pilot a willow propagation program in high priority riparian areas identified within the Waldo Canyon burn scar where post-fire vegetation recovery using traditional willow staking and other methods have not been successful to improve watershed health and stream function.

In January 2016, RMFI and U.S. Forest Service personnel spent some time in the field harvesting several species of willows off the Pikes Peak Highway. Species included narrowleaf willow (Salix exigua), scouler willow (Salix scouleriana), bebb willow (Salix bebbiana), and Rocky Mountain willow (Salix monticola Bebb). The cuttings were overnighted to the Bessey Nursery in Halsey, Nebraska where they will grow in pots for approximately 4 months. Around the end of May or early June, the plants will be trucked back to Colorado Springs for transplanting in priority riparian areas in the burn scar identified by the U.S. Forest Service. With the help of youth corps crews and volunteers, RMFI will use power augers to plant the willows as soon as the ground has thawed and the spring high water period has passed. The cuttings will be planted to a depth that will allow their bases to be at or near the level of the normal water table.

Two additional components of the project are monitoring the survivability rates of the willow transplants as well as completing complementary hillslope stabilization and erosion control treatments started by RMFI in other portions of the burn scar. Overall, this project will help increase the composition of native riparian plants, vegetative cover, structural diversity, and promote bank and channel stability.

We are very excited about this project and will continue to provide updates through social media and other outlets. We'll also be needing volunteer help and will post those announcements as soon as we can! Finallly, we'd like to send a big thank you to the Colorado Water Conservation Board and the Pikes Peak Community Foundation for funding this important work!