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M.G. Rollins

Publications and source records attributed to M.G. Rollins.

3 recordsLinked to original sources
USGS2009

Spatial fuel data products of the LANDFIRE Project

The Landscape Fire and Resource Management Planning Tools (LANDFIRE) Project is mapping wildland fuels, vegetation, and fire regime characteristics across the United States. The LANDFIRE project is unique because of its national scope, creating an integrated product suite at 30-m spatial resolution and complete spatial coverage of all lands within the 50 states. Here we describe development of the LANDFIRE wildland fuels data layers for the conterminous 48 states: surface fire behavior fuel models, canopy bulk density, canopy base height, canopy cover, and canopy height. Surface fire behavior fuel models are mapped by developing crosswalks to vegetation structure and composition created by LANDFIRE. Canopy fuels are mapped using regression trees relating field-referenced estimates of canopy base height and canopy bulk density to satellite imagery, biophysical gradients and vegetation structure and composition data. Here we focus on the methods and data used to create the fuel data products, discuss problems encountered with the data, provide an accuracy assessment, demonstrate recent use of the data during the 2007 fire season, and discuss ideas for updating, maintaining and improving LANDFIRE fuel data products.

International Journal of Wildland Fire↗
USGS2006

Ponderosa pine snag densities following multiple fires in the Gila Wilderness, New Mexico

Fires create and consume snags (standing dead trees), an important structural and ecological component of ponderosa pine forests. The effects of repeated fires on snag densities in ponderosa pine forests of the southwestern USA have not been studied. Line intercept sampling was used to estimate snag densities in areas of the Gila Wilderness that had burned one to three times under Wildland Fire Use for Resource Benefit (WFU), a fire management policy implemented since 1974 aimed at restoring natural fire regimes. Twenty randomly located transects were measured in areas burned since 1946; six in once-burned areas, six in twice-burned areas and eight in thrice-burned areas. The mean density ?? standard errors of large (>47.5 cm dbh) snags for areas that burned once, twice and thrice was 7.0 ?? 2.7, 4.4 ?? 1.1 and 4.1 ?? 1.3 snags/ha, respectively. Differences in snag densities between once- and multiple-burned areas were significant (F-test; p < 0.05). There was no significant difference in density of large snags between twice- and thrice-burned areas. Proportions of type 1 snags (recently created) were higher in once- and twice-burned areas than in areas that burned three times, likely reflecting high tree mortality and snag recruitment resulting from an initial entry fire. Type 3 snags (charred by previous fire) were more abundant in areas that burned multiple times. The lack of differences in snag densities between areas that burned two and three times suggests that repeated fires leave many snags standing. The increasing proportion of type 3 snags with repeated fires supports this conclusion. ?? 2005 Elsevier B.V. All rights reserved.

Forest Ecology and Management↗