Science for productive forests: Conserving soil, water, and wildlife
Soils
Increasing timber production and active forest management on National Forest System lands will require improved and new roads and landings. Engineers, hydrologists, and timber managers rely on agency-developed, science-based tools to evaluate road maintenance needs and erosion potential. For example, GRAIP-lite estimates road maintenance needs and predicts road sediment delivery to streams. It is more cost efficient and works at larger scales than field inventories.
To support forest managers as they estimate erosion potential of planned management activities and unplanned catastrophic events, scientists have spent over a decade developing a suite of online tools to predict the erosion potential of road building, forest management, and wildfire.
With agency land managers, Forest Service researchers monitor soil to ensure on-the-ground projects meet legal requirements. The Long Term Soil Productivity project—the largest, longest lasting study on forest management and soils in the world— underlies national and regional soil quality standards and best management practices.
Managers once thought that soils took a long time to recover after timber harvest—if they did at all. In a 20-year study with managers on the Kootenai National Forest, agency scientists found that soils on over 85 percent of units needed only 3-5 years to recover after timber harvest.
Agency scientists have shown that scale matters when assessing damage from logging equipment. While post-fire salvage logging using heavy equipment can compact soils, increase overland water flow, and increase erosion rates at small spatial scales, the effects are less detectable at larger spatial scales because of heterogeneous surface cover. Additionally, scientists found that adding slash cover to skid trails can reduce damage from heavy machinery. Other agency-developed best management practices, like guidelines for post-fire salvage logging, supplement state, regional, and national regulations and guidance for timber harvest.
Water
For over a century, Congress has mandated that national forests should ensure harvesting practices protect clean water. And for good reason: agency research shows that national forests and grasslands supply drinking water to almost 90 percent of people served by public water systems in the West. And within all lower 48 states, over 99 percent of people who rely on public drinking water systems receive some of their water from forested lands.
The agency’s decadal Resources Planning Act Assessment identifies current and projected future areas of water stress, which can inform where active management is most urgent to maintain or enhance watershed function. Projections of drought enable foresters and ranchers to plan for changing conditions; for example, ranchers can use this information to plan how many cow-calf pairs to purchase before the growing season. Users of the Assessment’s modeling framework can also simulate how different management interventions may affect hydrologic regimes. They can even request a specific analysis from Assessment authors.
The Forests to Faucets Assessment identifies the most important sources of water in the United States. The Assessment maps these watersheds and identifies potential threats, such as fire and land use change, to the continued delivery of water.
Loggers using agency-developed best management practices may be encouraging aquatic species diversity and abundance in North Carolina streams, shows agency research. This research suggests that responsible logging can not only be a part of healthy forests and waterways but can also lead to them.
Long term research at a California experimental forest helped established the logging-free buffer zones around waterways that are a best management practice for logging in the state. These buffer zones prevent pollution and support fish and wildlife living in and depending on clean waterways. Agency scientists in the state also suggest best management practices for salvage logging that help reduce the amount of soil eroding into waterways.
By surveying aquatic species downstream of a timber harvest in Oregon, agency scientists determined harvesting can impact areas much farther from the project site than previously realized. This research may help loggers use best management practices that avoid harming wildlife.
Aquatic invasive species economically harm agriculture, fisheries, and other industries. Industry partners use Forest Service tools to map the distribution of aquatic invasive species, which improves early detection, monitoring, control, and eradication efforts.
Across the United States, fisheries support 2.3 million jobs and have a combined value of almost $500 billion. Our scientists support these economic powerhouses by developing tools to track water quality at cold water sport fisheries.
Wildlife and Habitat
Forest managers can harvest timber while supporting thriving wildlife populations, and Forest Service science helps them accomplish these dual goals. For example, thinning and prescribed burning are likely necessary in some places to reduce the loss of late-successional forests—used by California spotted owl, fisher, and other wildlife—due to extreme fire and drought. And fuels treatments can coexist with California spotted owl recovery efforts, as demonstrated by agency research in the Sierra Nevada.
Mule deer (seen here), elk, horses and cattle seek the green grass that still grows late into the season on the Apache-Sitgreaves National Forests.
With Living Maps created by agency scientists, managers can monitor habitat for at-risk species in near-real time. These maps showed where wildlife habitat and forest management could be compatible on southwestern national forests, which helped lift an injunction on fuels management and timber harvest. Similarly, the National Aquatic Biodiversity Assessment Storymap and Data Dashboard show where species listed under the Endangered Species Act live.
Canada lynx require large and intact areas of mature forest—but their habitat is increasingly at risk of more frequent, severe fire. Our research has found that maintaining a mix of forest stands, including actively managed stands, supports Canada lynx habitat. Further research on remapping lynx habitat identified areas available for timber removal.
Game species such as mule deer, white-tailed deer, and elk bolster recreation-based economies—a fact well known to timber managers. Logging may benefit mule deer because habitats that develop post-harvest often contain a greater variety, quantity, and quality of forage than mature forests. Also, elk forage in nutrient-rich and biodiverse logged areas during the night but avoid these same low-canopy areas during the day, suggesting a need for both logged and unlogged areas in elk habitat.
Pollinators, especially butterflies, increased in number and species diversity after ponderosa pine harvest combined with prescribed fire in a northern California forest. In eastern forests, agency researchers are showing where unused log landings could be converted to pollinator habitat.
Agency scientists revealed how different harvest activities influence bird communities. They also developed FIRE-BIRD, a tool that maps bird habitat, to help managers avoid harvesting where birds thrive.
