1 | Bill Williams Mountain Steep Slope Forest Restoration Project

Bill Williams Mountain Steep Slope Forest Restoration Project

Reducing uncharacteristic fire and post-fire flooding risk, protecting mountain communities, local and downstream economies, water supplies, and a significant northern Arizona landscape.

The Bill Williams Mountain Steep Slope Forest Restoration Project is the most complex restoration project ever conducted by the Southwest Region of the National Forest Foundation (NFF) since establishing the Northern Arizona Forest Fund (NAFF) in 2015. Together with our partners, we are removing 100 years of overgrowth on some of the steepest terrain to protect both the landscape and the nearby city of Williams, AZ, from high-intensity fire and flooding.

When completed, the Bill Williams Mountain Restoration Project will have thinned 1,200 acres of the steepest slope at the top of Bill Williams Mountain. Those areas represent some of the highest wildfire risk and subsequent post-fire flooding. Although the estimated cost to treat these acres exceeds $30 million, the cost of doing nothing would be more than 10 times greater.

Donate to the Northern Arizona Forest Fund, which contributes to the costs of the Bill Williams Steep Slope Project.

Because the risk of high-severity fire is so extreme, it is not a question of 'if' a fire and subsequent flooding will occur, but rather 'when,' and how severe.

A 2017 study found that Bill Williams Mountain, on the Kaibab National Forest, is at high risk for extreme fire.

If the mountain burns in its current condition:

  • Communication and power infrastructure would be destroyed, knocking out electricity, air-conditioning, internet, and communications;
  • Even moderate post-fire rains would flood Williams in up to six feet of water and debris, devastating the downtown area, and flooding could go on for years;
  • Drinking water for communities all the way to Phoenix – 160 miles away – would be jeopardized;
  • The Grand Canyon Railway and Hotel would likely close permanently;
  • Interstate 40 and BNSF Railroad would flood and have to be shut down;
  • The estimated impact on the local economy would be between $379 million – $694 million in losses.

Removing hazardous fuels by air

Steep slope forest restoration is incredibly costly and complex but needed. Rocky, inaccessible parts of the mountain make a normal ground-based thinning operation impossible. Fuel reduction on steep slopes, like the ones found on Bill Williams Mountain, requires technical operations with specialized methods, including hand thinning and helicopters to remove fuels from the mountain.

Because of this, we are turning to the air and flying out material that would most likely contribute to uncharacteristic wildfire. According to prescribed treatments, smaller size classes of standing trees, dead and downed logs, and debris are all placed at a sorting area, known as a landing, in a more accessible location. This project explicitly requires the excess wood and debris to be entirely removed from the mountain, unlike other treatments that often chip or pile wood for future burning.

Treatment areas are strategically located to provide buffers from high-probability fire start zones, predominant wind directions, and areas that won’t be thinned, such as Mexican spotted owl core habitat.

Repurposing the wood

Finding plausible outlets for small-diameter wood is a challenge for forest restoration projects across the county. Where feasible, the NFF shares a portion of this type of wood removed from the mountain with the Wood for Life Tribal Fuelwood Initiative, which provides wood to Tribal communities who use it for heating homes, cooking and traditional uses.

Learn more about how the NFF is working to expand the benefits of forest restoration treatments in the Four Corners Region to Tribal communities in need of fuelwood for heating, cooking, and traditional uses through the Wood for Life Tribal Fuelwood Initiative.

The outcomes

The steep slope treatments are part of a greater landscape-scale effort on the mountain. The risk of active crown fire — often the most intense and difficult to contain — will be reduced by over 40% once restoration work is complete.

Reduced tree densities will also benefit the threatened Mexican spotted owl, which nests on the mountain. Mexican spotted owls breed in the spring and summer, and current regulations limit the time that crews can operate. Therefore, restoration work can only be accomplished in the fall after the breeding season but before snowfall.

We evaluate the impacts of our forest restoration projects, including BWM, by partnering with Conservation Science Partners to analyze the fire risk reduction from this work. Check out this map and zoom in to see several forest restoration project focal areas and use the dropdown menu to visualize biomass or fire activity reduced by treatments. Use the slider bar across the map to see pre- and post-treatment information

Stages of steep slope work

From 2019 – 2021, crews and helicopters thinned and removed excess wood on roughly 475 steep-slope acres. This year our efforts continue, and we are working on treating another 280 acres.

Check out this photo series to see images of tree felling, fuels and small-diameter tree removal, and before and afters of on-the-ground treatment areas!

Bill Williams Mountain Steep Slope Forest Restoration Project photo series


The Bill Williams Mountain Steep Slope Project is made possible through a dedicated network of partners. Celebrating the power of partnerships on our public lands illustrates how priority work is accomplished in real-time.

Partners include:


Rebecca Davidson, Southwest Region Director and Youth Programs Director, at rdavidson @nationalforests.org