Analysis of small-diameter wood supply in northern Arizona - Final report

Forest management to restore fire-adapted ponderosa pine ecosystems is a central priority of the Southwestern Region of the USDA Forest Service. Appropriately-scaled businesses are apt to play a key role in achieving this goal by harvesting, processing and selling wood products, thereby reducing treatment costs and providing economic opportunities. The manner in which treatments occur across northern Arizona, with its multiple jurisdictions and land management areas, is of vital concern to a diversity of stakeholder groups. To identify a level of forest thinning treatments and potential wood supply from restoration byproducts, a 20-member working group representing environmental non-governmental organizations (NGOs), private forest industries, local government, the Ecological Restoration Institute at Northern Arizona University (NAU), and state and federal land and resource management agencies was assembled. A series of seven workshops supported by Forest Ecosystem Restoration Analysis (ForestERA; NAU) staff were designed to consolidate geographic data and other spatial information and to synthesize potential treatment scenarios for a 2.4 million acre analysis area south of the Grand Canyon and across the Mogollon Plateau. A total of 94% of the analysis area is on National Forest lands. ForestERA developed up-to-date remote sensing-based forest structure data layers to inform the development of treatment scenarios, and to estimate wood volume in three tree diameter classes of 16" diameter at breast height (dbh, 4.5' above base). For the purposes of this report, the group selected a 16" dbh threshold due to its common use within the analysis landscape as a break point differentiating "small" and "large" diameter trees in the ponderosa pine forest type. The focus of this study was on small-diameter trees, although wood supply estimates include some trees >16" dbh where their removal was required to meet desired post-treatment conditions.4 There was no concurrence within the group that trees over 16" dbh should be cut and removed from areas outside community protection management areas (CPMAs)..

Models of Regional Habitat Quality and Connectivity for Pumas (<i>Puma concolor</i>) in the Southwestern United States

<div><p>The impact of landscape changes on the quality and connectivity of habitats for multiple wildlife species is of global conservation concern. In the southwestern United States, pumas (<i>Puma concolor</i>) are a well distributed and wide-ranging large carnivore that are sensitive to loss of habitat and to the disruption of pathways that connect their populations. We used an expert-based approach to define and derive variables hypothesized to influence the quality, location, and permeability of habitat for pumas within an area encompassing the entire states of Arizona and New Mexico. Survey results indicated that the presence of woodland and forest cover types, rugged terrain, and canyon bottom and ridgeline topography were expected to be important predictors of both high quality habitat and heightened permeability. As road density, distance to water, or human population density increased, the quality and permeability of habitats were predicted to decline. Using these results, we identified 67 high quality patches across the study area, and applied concepts from electronic circuit theory to estimate regional patterns of connectivity among these patches. Maps of current flow among individual pairs of patches highlighted possible pinch points along two major interstate highways. Current flow summed across all pairs of patches highlighted areas important for keeping the entire network connected, regardless of patch size. Cumulative current flow was highest in Arizona north of the Colorado River and around Grand Canyon National Park, and in the Sky Islands region owing to the many small habitat patches present. Our outputs present a first approximation of habitat quality and connectivity for dispersing pumas in the southwestern United States. Map results can be used to help target finer-scaled analyses in support of planning efforts concerned with the maintenance of puma metapopulation structure, as well as the protection of landscape features that facilitate the dispersal process.</p></div

Average (±1SD) of the expert-defined importance values and swing weights for the habitat variables (i.e., data layers) used to estimate habitat quality and permeability for dispersing pumas in Arizona and New Mexico.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081898#pone-0081898-t001" target="_blank">Table 1</a>.¹ Variable abbreviations defined in </p

Expert-defined habitat variables (data layer name) and associated classes, and average (±1SD) habitat quality and permeability scores used to estimate connectivity for pumas in Arizona and New Mexico.

<p>Expert-defined habitat variables (data layer name) and associated classes, and average (±1SD) habitat quality and permeability scores used to estimate connectivity for pumas in Arizona and New Mexico.</p

Map of habitat quality and high quality habitat patches for pumas.

<p>Estimates of habitat quality were derived using expert-elicited information and seven habitat variables. High quality habitat patches are uniquely numbered for reference. Background maps were produced using data obtained from the U.S. Geological Survey’s Earth Resources Observation and Science Center.</p

Models of habitat patch centrality.

<p>A) Centrality scores derived from summing total current flow across all pixels in each patch as it passes between all other patch pairs. B) Area-weighted centrality scores obtained by dividing scores in panel (A) by patch area. Background maps were produced using data obtained from the U.S. Geological Survey’s Earth Resources Observation and Science Center.</p