Landscape-scale changes in canopy fuels and potential fire behaviour following ponderosa pine restoration treatments

We evaluated canopy fuels and potential fire behaviour changes following landscape-scale restoration treatments in a ponderosa pine forest at Mt Trumbull, Arizona, USA. The goal of the project was to restore historical forest structure by thinning and burning, thereby reducing canopy fuels and minimising active crown fire potential. We measured 117 permanent plots before (1996–97) and after (2003) treatments. The plots were evenly distributed across the landscape and represented an area of ~1200 ha, about half of which was an untreated control. We compared canopy fuel estimates using three different methods to assess whether fire behaviour modelling outputs were sensitive to the choice of canopy fuel equation. Treatments decreased canopy fuel load by 43–50% from 0.77–1.83 kg m–2 to 0.44–0.91 kg m–2 (the range of values reflects the different canopy fuel equations) and decreased canopy bulk density by 42–61% from 0.038–0.172 kg m–3 to 0.022–0.067 kg m–3 in the treated area, while slight increases occurred in the control. We applied two fire models to estimate potential fire behaviour: FlamMap and NEXUS. These models differ in several important features but predicted outcomes were consistent: under extreme drought and wind conditions, the proportion of the landscape susceptible to active crown fire decreased in the treated area while little change occurred in the control.

[1]  Peter Z. Fulé,et al.  Restoring Ecosystem Health in Ponderosa Pine Forests of the Southwest , 1997, Journal of Forestry.

[2]  M. M. Moore,et al.  Diversity in Ponderosa Pine Forest Structure Following Ecological Restoration Treatments , 2003, Forest Science.

[3]  Charles E. Keegan,et al.  Reducing Crown Fire Hazard in Fire-Adapted Forests of New Mexico , 2003 .

[4]  Charles W. McHugh,et al.  Stand- and landscape-level effects of prescribed burning on two Arizona wildfires , 2005 .

[5]  K. Moore,et al.  Mt. Trumbull Ponderosa Pine Ecosystem Restoration Project , 2003 .

[6]  C. Allen,et al.  Effects of seeding ryegrass (Lolium multiflorum) on vegetation recovery following fire in a ponderosa pine (Pinus ponderosa) forest , 2004 .

[7]  M. M. Moore,et al.  DETERMINING REFERENCE CONDITIONS FOR ECOSYSTEM MANAGEMENT OF SOUTHWESTERN PONDEROSA PINE FORESTS , 1997 .

[8]  M. M. Moore,et al.  Natural variability in forests of the Grand Canyon, USA , 2002 .

[9]  Joe H. Scott,et al.  Estimating canopy fuels in conifer forests , 2002 .

[10]  Richard D. Stratton,et al.  Assessing the Effectiveness of Landscape Fuel Treatments on Fire Growth and Behavior , 2004, Journal of Forestry.

[11]  J. Ganey,et al.  Technical Note: A Comparison of Two Techniques for Measuring Canopy Closure , 1994 .

[12]  Miguel G. Cruz,et al.  Assessing canopy fuel stratum characteristics in crown fire prone fuel types of western North America , 2003 .

[13]  Russell T. Graham,et al.  Hayman Fire Case Study , 2003 .

[14]  James K. Brown.  Weight and density of crowns of Rocky Mountain conifers , 1978 .

[15]  Joy Nystrom Mast,et al.  How resilient are southwestern ponderosa pine forests after crown fires , 2005 .

[16]  J. W. Thomas,et al.  Wildlife habitats in managed forests--the Blue Mountains of Oregon and Washington , 1981 .

[17]  M. M. Moore,et al.  REFERENCE CONDITIONS AND ECOLOGICAL RESTORATION: A SOUTHWESTERN PONDEROSA PINE PERSPECTIVE , 1999 .

[18]  J. Bence,et al.  TEMPORAL AND SPATIAL VARIATION IN ENVIRONMENTAL IMPACT ASSESSMENT , 2001 .

[19]  Joe H. Scott,et al.  Assessing Crown Fire Potential by Linking Models of Surface and Crown Fire Behavior , 2003 .

[20]  Charles W. McHugh,et al.  Potential fire behavior is reduced following forest restoration treatments , 2001 .

[21]  Joe H. Scott.  Fuel reduction in residential and scenic forests: A comparison of three treatments in a western Montana ponderosa pine stand , 1998 .

[22]  M. Applequist.  A simple pith locator for use with off-center increment cores , 1958 .

[23]  M. M. Moore,et al.  Comparison of Historical and Contemporary Forest Structure and Composition on Permanent Plots in Southwestern Ponderosa Pine Forests , 2004 .

[24]  R. Youngs.  "A right smart little jolt": loss of the chestnut and a way of life. , 2000 .

[25]  D. L. Lynch,et al.  Forest Restoration in Southwestern Ponderosa Pine , 2000 .

[26]  Scott L. Stephens,et al.  Evaluation of the effects of silvicultural and fuels treatments on potential fire behaviour in Sierra Nevada mixed-conifer forests , 1998 .

[27]  M. Finney.  FARSITE : Fire Area Simulator : model development and evaluation , 1998 .

[28]  Patricia L. Andrews,et al.  Introduction To Wildland Fire , 1984 .

[29]  C. E. Van Wagner,et al.  Conditions for the start and spread of crown fire , 1977 .

[30]  M. Stokes,et al.  An Introduction to Tree-Ring Dating , 1996 .

[31]  Donald McKenzie,et al.  Climatic Change, Wildfire, and Conservation , 2004 .

[32]  P. Gould,et al.  Slash Compression Treatment Reduced Tree Mortality from Prescribed Fire in Southwestern Ponderosa Pine , 2004 .

[33]  Philip N. Omi,et al.  Performance of Fuel Treatments Subjected to Wildfires , 2003 .

[34]  W. Wallace Covington,et al.  Helping western forests heal , 2000, Nature.

[35]  W. Clary,et al.  Distribution of biomass within small tree and shrub form Quercus gambelii stands , 1986 .

[36]  Peter Z. Fulé,et al.  Comparing ecological restoration alternatives: Grand Canyon, Arizona , 2002 .

[37]  M. M. Moore,et al.  RESTORATION OF PRESETTLEMENT AGE STRUCTURE OF AN ARIZONA PONDEROSA PINE FOREST , 1999 .

[38]  P. Fulé,et al.  Pre-wildfire fuel treatments affect long-term ponderosa pine forest dynamics , 2007 .

[39]  Peter Z. Fulé,et al.  Measuring forest restoration effectiveness in reducing hazardous fuels , 2001 .

[40]  K. Elliott,et al.  Biomass distribution and productivity of Pinus edulis-Juniperus monosperma woodlands of north-central Arizona , 1992 .

[41]  Alan S. White.  Presettlement regeneration patterns in a southwestern Ponderosa pine stand , 1985 .

[42]  C. E. Van Wagner,et al.  Prediction of crown fire behavior in two stands of jack pine , 1993 .

[43]  M. M. Moore,et al.  Changes in canopy fuels and potential fire behavior 1880-2040: Grand Canyon, Arizona , 2004 .

[44]  C. Allen,et al.  ECOLOGICAL RESTORATION OF SOUTHWESTERN PONDEROSA PINE ECOSYSTEMS: A BROAD PERSPECTIVE , 2002 .

[45]  Philip N. Omi,et al.  Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests , 2002 .