Riparian Restoration Supports Healthy Forests

Introduction

Image Details

As climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change advances, droughts are intensifying and wildfires are becoming increasingly severe across the Southwestern U.S. Protecting water resources and wetland habitats is critical for arid forest ecosystems to adapt to these environmental changes. Restoration efforts in riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian areas - streams, wetlands, and wet meadows - are a key focus of Arizona’s Four Forest Restoration Initiative (4FRI). 4FRI is a multi-stakeholder collaborative effort to improve forest health and promote natural, beneficial wildfire patterns across ponderosa pine forests on 2.4 million acres of the Kaibab, Coconino, Apache-Sitgreaves, and Tonto National Forests in Arizona. These forests provide important ecosystem services to surrounding communities, including food and wood resources, clean air and water, and recreational opportunities. These public lands also harbor invaluable water resources, cultural significance, and rich biodiversity. Historical exclusion of beneficial fire and unsustainable land uses contributed to dense, unhealthy forest conditions in this region. These impacts are compounded by climate change, which is intensifying droughts and flash floods, and amplifying the risk of unnaturally severe wildfires.

These environmental changes are taking place at large landscape scales, with impacts crossing administrative forest boundaries. Recognizing the need to coordinate and accelerate restoration, a group of about 30 stakeholders formalized a collaboration with the U.S. Forest Service (USFS) to form the Four Forest Restoration Initiative (4FRI) in 2011. Stakeholder Group members include representatives from Arizona’s state and local governments, federal agencies, universities, non-governmental organizations, forestry industries, and other interested groups. The Stakeholder Group has helped inform the USFS planning process for 4FRI and collaborates on restoration implementation and monitoring. 

In addition to selective tree removal and prescribed fire, a key component of 4FRI’s work is watershed-scale riparian restoration, where they focus on restoring springs, wet meadows, and streams. Maintaining these wetland habitats supports biodiversity, climate adaptation, and overall forest health, while protecting water resources for local communities.

Key Issues Addressed

After Euro-American settlement in the Southwestern US and displacement of Native peoples amplified in the 19th century, different and more extractive practices took place across the region’s ponderosa pine forests. This included widespread removal of old growth forests, grazing of unsustainably large livestock herds, and exclusion of regenerative, beneficial fire. During this time, many springs were constrained and overused while wetland-building beavers were hunted to near-extirpation, dramatically reducing riparian habitat in some areas. Even as federal-level forest management took hold in the early 20th century, some practices continued to impact forest health, shifting wildfire patterns from frequent low-intensity burns that naturally thinned young trees to unprecedented high-severity blazes consuming thousands of dense, dry acres. Today, advancing climate change further threatens riparian areas with intensifying drought and warming temperatures. Precipitation patterns are also shifting as storms become more sporadic but release more rainfall in single events onto drier, less permeable soils. These combined factors can cause streams to become eroded and incised channels, disconnecting annual flows from their larger floodplains and shrinking wetland habitats. These erosion impacts are compounded by overpopulated elk and livestock which preferentially graze and trample on wetland areas.

Though some riparian areas may only have seasonal flows or cover a small footprint, they support relatively higher biodiversity than surrounding upland areas, act as moisture-rich fuel breaks during wildfires, and provide refuge habitats that help buffer species from advancing climate change. During floods, healthy wet meadows can act as sponges that help absorb and slow flows. Healthy riparian areas also provide water resources which help fill reservoirs and provide drinking water to downstream communities. Protecting and restoring riparian areas is key to climate resilience across 4FRI forests and is an important component in the collaboration’s broader forest restoration efforts.

Project Goals

• Protect and restore springs, wet meadows, and streams. Restore degraded riparian areas using best-available science to minimize catastrophic wildfire threats, protect wildlife habitat and water resources, and build resilience to climate change.
• Evaluate restoration approaches though monitoring and scale-up restoration work across 4FRI.
• Increase awareness of riparian areas in national forests as important habitats and water resources.

Project Highlights

Raising Riparian Awareness: The public can support riparian restoration by learning about threats to waters and wetlands, volunteering for restoration projects, and advocating for water and wetland protection through national forest public comment opportunities.

• Diverse Approaches to Riparian Restoration Contribute to Landscape Health: 4FRI implements a range of riparian restoration techniques. Elk and livestock exclosures are fences that surround riparian areas to minimize grazing and keep vehicles out, allowing native plants to recover. Well-placed rock structures like one-rock dams and rock-lined bowls reduce stream channelization, reverse erosion, and help reconnect water flow with the broader floodplain. Reintroducing native willow trees stabilizes soils, revegetates stream banks, and provides shade, which reduces moisture loss and creates wildlife habitat. 
• Methods to Evaluate Success Vary by Restoration Technique: 4FRI stakeholders take photos before and one year after management at each site to visually compare changes in flow and channelization. To evaluate vegetation regrowth, botany volunteers identify plant species across annual transects before and for two to four years after management. Monitoring riparian obligate plant species like willows and conducting dry season soil-moisture-by-feel tests helps 4FRI understand the extent of wetland in a restoration area. 
• Drone Imagery Suggests Restoration Success: 4FRI worked with the U.S. Geological Survey who flew a drone over a spring restoration site. The initial thermal and high-resolution imagery showed greener vegetation and wetter areas where exclosures protected native plants from overgrazing, demonstrating the possibility of using drones for future planning and monitoring at restoration sites.
• Volunteers Play Critical Role in Implementing Restoration: Volunteers who donate their time and expertise are critical to the installation and maintenance of restoration tools such as rock structures and grazing exclosures. Riparian restoration is supported by volunteers from many organizations active in northern Arizona, including the Arizona Elk Society, Friends of Northern Arizona Forests, and the Grand Canyon Trust.

Lessons Learned

Image Details

One key lesson from this riparian restoration work is that approaches that “let the water do the work” (Zeedyk and Clothier 2009) can be some of the most successful. One-rock dams and rock-lined bowls are two hand-built structures that help heal eroded riparian areas by reconnecting stream flows with broader floodplains. One-rock dams are tightly packed beds of rocks, typically one rock tall and several rocks wide, placed upstream of and across a narrowing channel perpendicular to stream flow. These help to slow and spread water across a floodplain, promoting wet meadow habitats and reducing channelization. In areas where channels have formed headcuts (vertical drops), rock-lined bowls shaped out of carefully stacked rocks can halt deepening channels, protect banks, and slow and spread flow, especially during flash events. These structures can be constructed by hand using local materials and provide temporary “sutures” that help reconnect eroded areas while flows reconnect and wetland plants regrow. When coupled with strategically placed exclosure fences which protect wetlands from grazing and trampling, these approaches can be especially effective.

This restoration can be an iterative process: restoring a wetland may require multiple visits and approaches. 4FRI appreciates the uniqueness of every riparian system and acknowledges that not every restoration tool will be feasible at every location. Yet, increasing the pace and scale of this riparian restoration work is critical for improving overall forest and watershed health and mitigating both the risk and impacts of unnaturally severe wildfire. This expanding implementation engages a range of resources, teams, and other ongoing support – from funding for materials, to field-based knowledge for planning, to support for teams on the ground placing rocks, planting willows, or constructing protective fences. Waters and wetlands are invaluable in our arid Southwestern national forests, and advancing this work represents a true collaborative effort.

Next Steps

• Expand monitoring approaches: 4FRI recently partnered with the U.S. Geological Survey (USGS) to expand a pilot monitoring project using drone-based imagery. 4FRI and USGS hope to evolve their use of drones to map out needs for restoration and to further explore the effects of riparian restoration actions.
• Scale-up riparian restoration work across 4FRI: 4FRI is a 2.4-million acre forest restoration effort happening at a necessarily large but practically unprecedented scale. Alongside 4FRI’s selective tree removal and prescribed burning approaches, the group is working to also scale up its protection and restoration of springs, streams, and wet meadows from site-specific levels to watershed levels across 4FRI. While there is widespread support for scaling up these efforts, the collaboration is working to boost capacity and planning to meet these needs.
• Continue on-the-ground restoration actions: Various riparian restoration projects are in the process of being implemented across 4FRI, whether they be upgrading protective exclosure fences, repairing or adding new erosion control rock structures, or watershed-wide flow analyses to inform planning and prioritization of future projects.

Funding Partners

Funding, materials, and on-the-ground work and expertise have been generously donated by dedicated staff and volunteers from the U.S. Forest Service, Arizona Game and Fish Department, Friends of Northern Arizona Forests, Arizona Elk Society, Grand Canyon Trust, National Forest Foundation, and related donors and supporters.

References

• 4FRI Website
• USDA 4FRI Overview
• 4FRI Brochure
• The History of 4FRI
• U.S. Forest Service Website
• 4FRI Stakeholders List
• 4FRI Environmental Impact Statement (EIS)
• Collaborative Forest Landscape Restoration Program Website
• 4FRI Working Groups
• Explanation of Elk and Livestock Exclosures
• Explanation of Rock Structures for Restoration
• U.S. Geological Survey Website
• Zeedyk, B. and Clothier, V. (2014). Let the water do the work: Induced meandering, an evolving method for restoring. Chelsea Green Publishing.

Contact

Cerissa Hoglander, Grand Canyon Trust: choglander@grandcanyontrust.org

CART Lead Author

Erin Connolly, Case Study Author,  Drought Learning Network (DLN): connolly.erinelizabeth@gmail.com

The DLN is a peer-to-peer knowledge exchange between climate service providers and resource managers, created to gather and share lessons learned from drought events to prepare for future events. The DLN partners with CART to develop Case Studies, with funding from the National Drought Mitigation Center for interns and coordination support from the USDA Southwest Climate Hub.

Suggested Citation

Connolly, E. E. “Riparian Restoration Supports Healthy Forests in Northern Arizona.” CART. Retrieved from https://www.fws.gov/project/riparian-restoration-supports-healthy-forests.