Critical Loads of Atmospheric Nitrogen and Sulfur Deposition for Protection of Sensitive Aquatic and Terrestrial Resources in the Intermountain Region of the USDA Forest Service T.C. McDonnell T.J. Sullivan D.L. Moore E&S Environmental Chemistry, Inc. Corvallis, OR September 27, 2019 TABLE OF CONTENTS List of Figures .................................................................................................................................v List of Tables .............................................................................................................................. xix Acknowledgments ...................................................................................................................... xxi Executive Summary .................................................................................................................. xxii 1 Background ......................................................................................................................... 1-1 1.1 Pollutants of Concern .................................................................................................. 1-1 1.2 Ecosystem Effects of Air Pollution ............................................................................. 1-1 1.3 Critical Loads and Forest Planning ............................................................................. 1-2 2 Objectives ............................................................................................................................ 2-1 3 Critical Load Databases ..................................................................................................... 3-1 3.1 Surface Water Acidification ........................................................................................ 3-1 3.2 Surface Water Eutrophication ..................................................................................... 3-2 3.3 Lichen Species Richness and Abundance ................................................................... 3-3 3.4 Tree Growth and Survival ........................................................................................... 3-5 3.5 Herbaceous Plants and Mycorrhizae ........................................................................... 3-6 4 Approach ............................................................................................................................. 4-1 4.1 Surface Water Acidification ........................................................................................ 4-1 4.2 Surface Water Eutrophication ..................................................................................... 4-7 4.3 Lichen Species Richness and Abundance ................................................................... 4-7 4.4 Tree Growth and Survival ........................................................................................... 4-8 5 Results and Discussion ....................................................................................................... 5-1 5.1 Summary Data Tables ................................................................................................. 5-1 5.1.1 Surface Water Acidification ............................................................................ 5-1 5.1.2 Surface Water Eutrophication ......................................................................... 5-1 5.1.3 Lichen Species Richness and Abundance ....................................................... 5-4 5.1.4 Tree Growth and Survival ............................................................................... 5-5 5.2 Results by National Forest ........................................................................................ 5-12 5.2.1 Ashley NF ..................................................................................................... 5-12 5.2.1.1 Surface Water Acidification ........................................................... 5-12 5.2.1.2 Surface Water Eutrophication ......................................................... 5-12 5.2.1.3 Lichen Species Richness and Abundance ....................................... 5-12 5.2.1.4 Tree Growth and Survival .............................................................. 5-19 5.2.2 Boise NF ....................................................................................................... 5-26 5.2.2.1 Surface Water Acidification ........................................................... 5-26 5.2.2.2 Surface Water Eutrophication ......................................................... 5-26 5.2.2.3 Lichen Species Richness and Abundance ....................................... 5-26 5.2.2.4 Tree Growth and Survival .............................................................. 5-26 ii 5.2.3 Bridger-Teton NF .......................................................................................... 5-40 5.2.3.1 Surface Water Acidification ........................................................... 5-40 5.2.3.2 Surface Water Eutrophication ......................................................... 5-40 5.2.3.3 Lichen Species Richness and Abundance ....................................... 5-40 5.2.3.4 Tree Growth and Survival .............................................................. 5-47 5.2.4 Caribou-Targhee NF ..................................................................................... 5-56 5.2.4.1 Surface Water Acidification ........................................................... 5-56 5.2.4.2 Surface Water Eutrophication ......................................................... 5-56 5.2.4.3 Lichen Species Richness and Abundance ....................................... 5-56 5.2.4.4 Tree Growth and Survival .............................................................. 5-63 5.2.5 Dixie NF ........................................................................................................ 5-69 5.2.5.1 Surface Water Acidification ........................................................... 5-69 5.2.5.2 Surface Water Eutrophication ......................................................... 5-69 5.2.5.3 Lichen Species Richness and Abundance ....................................... 5-69 5.2.5.4 Tree Growth and Survival .............................................................. 5-76 5.2.6 Fishlake NF ................................................................................................... 5-85 5.2.6.1 Surface Water Acidification ........................................................... 5-85 5.2.6.2 Surface Water Eutrophication ......................................................... 5-85 5.2.6.3 Lichen Species Richness and Abundance ....................................... 5-85 5.2.6.4 Tree Growth and Survival .............................................................. 5-92 5.2.7 Humboldt-Toiyabe NF ................................................................................ 5-101 5.2.7.1 Surface Water Acidification ......................................................... 5-101 5.2.7.2 Surface Water Eutrophication ....................................................... 5-101 5.2.7.3 Lichen Species Richness and Abundance ..................................... 5-101 5.2.7.4 Tree Growth and Survival ............................................................ 5-113 5.2.8 Manti-La Sal NF ......................................................................................... 5-150 5.2.8.1 Surface Water Acidification ......................................................... 5-150 5.2.8.2 Surface Water Eutrophication ....................................................... 5-150 5.2.8.3 Lichen Species Richness and Abundance ..................................... 5-150 5.2.8.4 Tree Growth and Survival ............................................................ 5-157 5.2.9 Payette NF ................................................................................................... 5-166 5.2.9.1 Surface Water Acidification ......................................................... 5-166 5.2.9.2 Surface Water Eutrophication ....................................................... 5-166 5.2.9.3 Lichen Species Richness and Abundance ..................................... 5-166 5.2.9.4 Tree Growth and Survival ............................................................ 5-171 5.2.10 Salmon-Challis NF ...................................................................................... 5-180 5.2.10.1 Surface Water Acidification ......................................................... 5-180 5.2.10.2 Surface Water Eutrophication ....................................................... 5-180 iii 5.2.10.3 Lichen Species Richness and Abundance ..................................... 5-180 5.2.10.4 Tree Growth and Survival ............................................................ 5-185 5.2.11 Sawtooth NF ............................................................................................... 5-194 5.2.11.1 Surface Water Acidification ......................................................... 5-194 5.2.11.2 Surface Water Eutrophication ....................................................... 5-194 5.2.11.3 Lichen Species Richness and Abundance ..................................... 5-194 5.2.11.4 Tree Growth and Survival ............................................................ 5-201 5.2.12 Uinta-Wasatch-Cache NF ........................................................................... 5-212 5.2.12.1 Surface Water Acidification ......................................................... 5-212 5.2.12.2 Surface Water Eutrophication