Natural Process Restoration Model Overview

The overall goal of the Southwest Forest Alliance's Natural Processes Restoration (NPR) model is to reintroduce or enhance natural processes such as frequent fire, hydrological cycles, nutrient cycles, and competition that shaped forests prior to European settlement. High priority objectives include significant reduction of the potential for large crown fires, decreasing competition among trees that results from excessive tree densities, as well as protecting and enhancing habitat for imperiled and sensitive species. The NPR model seeks to increase the diversity and quantity of the understory vegetation component through the definition of a network of well-defined openings between tree groups and a variety of thinning intensities within tree groups.

The NPR model is a conservative, light touch, restoration approach that is based upon the concept that structural manipulation should consist of only that minimally needed to allow natural ecological processes (particularly low intensity fire) to function again in shaping the structure of ponderosa pine forests. The comparatively conservative approach of the NPR model strives to reverse the downward trend in ecological health while explicitly incorporating the habitat needs of imperiled and indicator wildlife species.

The NPR's minimal structural manipulation approach recognizes that restoration is not a single event, but a process that occurs over time. Beginning the restoration process with minimal structural manipulation does not direct the forest to look a certain way, but instead creates conditions that enable natural ecological processes to become shaping agents of the forest over time. Minimal structural manipulation at the outset of the restoration process leaves options open for the future as more is learned about the practice and effectiveness of ecological restoration.

Natural Processes Restoration incorporates a variety of treatment options across a restoration area including a non-treatment option for some parts of an area, treatments that involve no removal of material from the site, minimal thinning prescriptions, as well as burn only options. It also considers landscape patterns and scale issues, as well as wildlife habitat requirements in determining the pattern and intensity of all types of treatment.

Goals

The Natural Processes Restoration model works to achieve the following goals:

• Restore forest structures, processes, and composition so they are within their natural range of variability.
• Increase resilience of the ecosystem to disturbance events, including fire, drought, insects, and regional climate fluctuations.
• Prepare the forest for, and reintroduce the fire process at appropriate frequency, extent, seasonality, and intensity.
• Reduce the risk of large high intensity fires and associated soil and watershed damage.
• Reduce anomalous densities of small-sized trees.
• Restore the natural range of trees ages, sizes, and spatial patterns.
• Restore habitat conditions for sensitive and declining species.
• Incorporate restoration strategies that protect interim habitats for imperiled species.
• Protect and invigorate the remaining old-growth trees.

General Restoration Strategy

Natural Processes Restoration is an integrated approach that includes: prescribed fire, conservative thinning, grazing deferment, erosion control, road closures, native seed planting, and intensive ecological monitoring. Some specific strategies include:

• Retain all large or old conifer trees (16" dbh or greater) and snags.
• Retain all oaks and aspen.
• Retain representatives of 20th century regeneration pulses.
• Incorporate best currently existing forest structures.
• Ensure interim and long-term habitat for sensitive plants and animals.
• Introduce frequent low intensity fire.
• Monitor the effects of restoration treatments

Implementation Principles

• In order to maintain habitat structures currently important to plants and wildlife, and to ensure that forests develop quickly toward their natural range of variability, restoration efforts will take advantage of valuable existing forest structures such as large trees, group structures, and canopies.
• Restoration of the natural clumpiness typical of ponderosa pine forests will be accomplished by identifying and retaining the larger, more vigorous trees currently on the landscape. Groups created around these trees will retain full canopies that will function, as best as possible, like pre-disturbance groups.
• Natural Processes Restoration works to restore ecological as well visual diversity to homogenous and degraded forests. Ponderosa pine forests historically contained a percentage of trees that were saplings, poles, and blackjack sized trees. To account for this, a diversity of tree sizes will be retained both within tree groups as well as across the restoration treatment area. Removing all of the smaller trees would result in oversimplification of the forest's structure and distribution of trees by age class. However, the majority of the trees thinned are under 9" dbh.
• Horizontal and vertical diversity similar to pristine forests will be retained where possible. The range of natural variability will be incorporated into the marking guide, allowing for a range of stems/acre, basal areas, and canopy covers.
• All yellow and yellowing pines will be retained regardless of size. Trees established before 1900 will be retained as well.
• Most of the trees immediately surrounding yellow pines will be aggressively thinned to reduce the risk of crown fire and competition from overstocking. Some blackjack or younger trees may be retained in these groups to replace old trees removed by logging and to provide a diversity of trees at various ages that will serve to perpetuate the yellow pine tree groups over time.
• Significant effort will be made to enhance existing oak groups as well as encourage oak regeneration by thinning overstory pines that are shading oak groups. No thinning within oak groups will occur. The 16" dbh diameter cap for ponderosa pine applies even when thinning for oak enhancement.
• All dead standing snags will be preserved. All downed logs greater than 10" diameter will be preserved. Efforts to protect these snags and downed material will be made during the initial prescribed fire treatments.
• All slash will be lopped, scattered, and left onsite to provide material for nutrient cycling and fuel for initial fire treatments. Excessive duff will be raked away from the boles of yellow pines prior to the introduction of prescribed fire.
• Wildlife cover areas adjacent to drainages, roads, and water sources will be identified and will be marked as non-treatment zones. Attention will also be paid to travel corridors between cover areas as well as small patches of cover between the larger designated cover areas.
• Livestock grazing deferment should occur following the initial fire treatment to allow for understory recovery. Long-term or permanent deferral is most desirable.
• No new roads will be constructed. Over time there will be a reduction in road densities, allowing for more natural fire regimes, less habitat fragmentation, and larger roadless areas.

SOUTHWEST FOREST ALLIANCE

Founded in 1994, the Southwest Forest Alliance is a coalition of environmental and sportsman organizations-with over 50,000 members-in Arizona and New Mexico charting a new course for the Southwest's public lands. The Alliance is dedicated to restoring a natural balance to our public lands by promoting solutions that preserve the remaining mature and old-growth forests and restoring degraded watersheds and forest ecosystems. This vision includes working for positive changes in forest management while helping forest-dependent communities become self-sustaining. The Alliance seeks to create the need for large-scale change in the Bureau of Land Management's and the Forest Service's land management practices by highlighting problems at the local level. The Alliance, in concert with its member organizations, also works to protect regional biodiversity and natural ecosystem integrity by seeking legal protection of candidate species under the Endangered Species Act and by advocating permanent protection of lands as Congressionally designated Wilderness.

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