FINAL REPORT Post-Fire Landscape Management and Fire Severity Influences in Western Oregon Forests
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FINAL REPORT Post-fire landscape management and fire severity influences in Western Oregon forests JFSP PROJECT ID: 16-1-05-11 31 October 2020 J Boone Kauffman Department of Fisheries and Wildlife Oregon State University Corvallis OR, 97331 Lisa Ellsworth Department of Fisheries and Wildlife Oregon State University Corvallis OR, 97331 David Bell, USFS, PNW Research Station Corvallis OR, 97331 Jane Kertis USDA Forest Service Corvallis, OR 97331 Steve Acker USDA Forest Service Sandy, OR 97055 The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government. Table of Contents Part 1. Forest structure and biomass reflects the variable effects of fire and land use 15 and 29 years following fire in the western Cascades, Oregon ...................................................... 5 Part II. Reburn intensity modified by fire severity and forest management in mesic mixed conifer forests .................................................................................................................................................................... 44 Appendix A: Contact Information for Key Project Personnel ................................................................... 63 Appendix B. List of Completed/Planned Scientific/Technical Publications/Science Delivery Products…………………………………………………………………………………………67 Appendix C. Data Management…………………………………………………………………70 List of Tables Table 1. Specific gravity (g cm-3), mean diameter (cm) and the quadratic mean diameter (cm) of dead wood samples in low to high severity fires, Warner Creek Aug 2017 (29 years following fire)…………………………………………………………………………………………….29 Table 2. Basal area and density of standing live and dead trees partitioned by large trees (prefire establishment and >10 cm dbh) and small trees (post fire establishment and <10 cm dbh). Numbers are mean with standard errors in parentheses. The P values are results of the Analysis of Variance testing for differences between the land use/fire cover types. Different superscripted letters note a significant difference between the land use/fire cover types…………………..30 Table 3. Forest biomass 26-29 years following fire at the Warner Creek Fires, Willamette National Forest, Oregon. Numbers are means (Mg ha-1) and one standard error (in parentheses). P values are results of the Analysis of Variance testing for differences between the land use/fire cover types. Different superscripted letters note a significant difference between the land use/fire cover types……31 Table 4. Forest biomass 15 years following fire at Apple Fire, Umpqua National Forest, Oregon. Numbers are means (Mg ha-1) and one standard error (in parentheses). P values are results of the Analysis of Variance testing for differences between the land use/fire cover types. Different superscripted letters note a significant difference (P≤,0.10) between the different land cover types (fires and land uses.)……………………………………………………………………………………………………32 Supplementary Table 1. Equations utilized to determine ecosystem biomass, fuel loads and aboveground carbon stocks. All diameters are in cm; all mass is in kg……………………….38 Supplementary Table 2. Depth of organic horizons (cm) and mass (Mg. ha-1) of the Apple and Warner Creek Fires, Western Oregon, 2017……………………………………………………………………….43 List of Figures Figure I-1. The fire perimeters and burn severity (% live tree basal area loss) of study sites in mixed severity fire regime/forest landscapes of the Willamette and Umpqua National Forests, Oregon (Reiley et al. 2017)……………………………………………………………………..26 Figure I-2. Experimental plot layout for quantification of species composition and total aboveground biomass of forests. Components include live and dead trees (measured in circular plots depending upon size), downed wood (measured in 4 transects per subplot, and litter and duff mass (measured along fuel transects). …………………………………………………27 Figure I-3. The relationship of the depth of the organic horizon (cm) to its mass (g cm-2). Figure I-4. The composition of woody vegetation that established following fire at the Warner Creek. Fires. Data are the percent of the total live biomass that is comprised by each species. Species abbreviations are: ACCI - Acer circinatum, ACMA - Acer macrophyllum, ALRU - Alnus rubra, CEVE - Ceanothus velutinus, CHCH - Chrysolepis chrysophylla, COCO – Corylus cornuta, FRLA – Fraxinus latifolia, PSME – Pseudotsuga menziesii, QUGA – Quercus garryana, THPL - Thuja plicata, TSHE - Tsuga heterophylla, and VAPA - Vacciniun parviflorum…………………………………………………………………………………28 Figure I-5. The composition of woody vegetation that established following fire at the Apple Fire, 2017. Data are the percent of the total live biomass that is comprised by each species. Species abbreviations are: ACCI - Acer circinatum, ACMA - Acer macrophyllum, ALRU - Alnus rubra, ARCO - Arctostphylos Columbiana, ARME - Arbutus menziesii , BETULA - Betula sp, CADE - Calocedrus decurrans, CESA - Ceanothus sanguineas, CEVE - Ceanothus velutinus, CHCH - Chrysolepis chrysophylla, COCO – Corylus cornuta, CONU - Cornus nutallii, HODI - Holodiscus discolor, PIPO - Pinus ponderosa, PSME – Pseudotsuga menziesii, QUGA – Quercus garryana, and VAPA - Vacciniun parviflorum……………………………………………………………………………………..29 Figure I-6. Total aboveground biomass (Mg ha-1) of managed (plantations and salvage-logged) and natural (burned late successional forests). Vertical small bars are one standard error of the total aboveground biomass………………………..……………………………………………………………….30 Figure II-1. Study areas included the Warner Creek and Shady Beach fires (top right) and Apple fire (bottom left) in mesic mixed conifer forests with mixed severity fire regimes of the Willamette and Umpqua National Forests, Oregon, USA. Burn severity within the fire perimeter is based on basal area mortality of tree canopy (modified from Kauffman et al 2019). …………………………………………………………………………………………………50 Figure II-2. Summary of fuel loads in 15 year old Apple fire and 29 year old Warner fires in mesic mixed conifer forests with mixed severity fire regimes of the Willamette and Umpqua National Forests, Oregon, USA…………………………………………………………………54 Figure II-3. Rate of modeled fire spread (m min-1), flame length (m), and reaction intensity (kW m-2 min-1) of a reburn 15 years after wildfire in high severity, moderate severity, low severity, plantation, and salvage logged plots across four curing scenarios (fully green, ⅓ cured, ⅔ cured, and fully cured) at the Apple Fires on the Umpqua National Forest, OR, USA……………………………………………………………………………………..………56. Figure II-4. Rate of modeled fire spread (m min-1), flame length (m), and reaction intensity (kW m-2 min-1) of a reburn 15 years after wildfire in high severity, moderate severity, low severity, plantation, and salvage logged plots in a fully cured moisture scenario at the Apple Fires on the Umpqua National Forest, OR, USA. Lines within boxes represent treatment means; error bars represent one standard error; different letters represent significant differences among treatments. Flame lengths less than 1.2 m (4 ft; dashed line) are typically fought with hand lines. Flame lengths between 1.2-2.4 m (4-8 ft) require heavy equipment, such as bulldozers, fire retardant, and helicopter drops. Flame lengths above 2.4 m (8 ft; solid line) are indicative of crowning, spotting, and running fires that are difficult for suppression resources to safely control. ………57 Figure II-5. Rate of modeled fire spread (m min-1), flame length (m), and reaction intensity (kW m-2 min-1) of a reburn 29 years after wildfire in high severity, moderate severity, low severity, plantation, and salvage logged plots across four curing scenarios (fully green, ⅓ cured, ⅔ cured, and fully cured) at the Warner Fires near Oakridge, OR, USA. ………………………………59 Figure II-6. Rate of modeled fire spread (m min-1), flame length (m), and reaction intensity (kW m-2 min-1) of a reburn 29 years after wildfire in high severity, moderate severity, low severity, plantation, and salvage logged plots in a fully cured moisture scenario at the Warner Fires near Oakridge, OR, USA. Lines within boxes represent treatment means; error bars represent one standard error; different letters represent significant differences among treatments. Flame lengths less than 1.2 m (4 ft; dashed line) are typically fought with hand lines. Flame lengths between 1.2-2.4 m (4-8 ft) require heavy equipment, such as bulldozers, fire retardant, and helicopter drops. Flame lengths above 2.4 m (8 ft; solid line) are indicative of crowning, spotting, and running fires that are difficult for suppression resources to safely control. ………………….60 Acknowledgements This study was funded by the US Joint Fire Sciences Program JFSP PROJECT ID: 16-1-05- 11.. We thank Raymond Davis and Matthew Reilly for conversations regarding the development of this research project. We wish to thank Dani Jackson, Becca Crawford, Trevor Bavarskas, Jacob Dittel, Jim Kelly, Leila Giovannoni, and Nick Dunstan for assistance in the field. We also wish to thank personnel from the Middle Fork and North Umpqua Districts of the Willamette and Umpqua National Forests. Abstract for the entire project The mixed severity fire regime of western Oregon forests creates a complex post-fire landscape mosaic with patches of low, moderate and high overstory tree mortality that modifies fuel loads and reburn fire behavior.