FINAL 

Development of 2000-04 

Baseline Period and 2018 

Projection Year Emission 

Inventories 

WESTERN GOVERNORS 

ASSOCIATION / WESTERN REGIONAL 

AIR PARTNERSHIP

PROJECT NO. 178-8 

MAY 2007 
WRAP Fire Ph3-4 EI Report_20070515.doc ii

CONTENTS Page

EXECUTIVE SUMMARY ...............................................................................................................................................E-1

1 INTRODUCTION............................................................................................................................................................ 1

1.1 Fire Inventory Calculation Tool............................................................................................................................... 2

1.2 Quality Assurance/Quality Control.......................................................................................................................... 3

1.3 National Inventory Format (NIF) Files..................................................................................................................... 3

2 BASELINE (2000 – 04) FIRE EMISSION INVENTORIES............................................................................................. 4

2.1 Wildfire Baseline Inventory ..................................................................................................................................... 4

2.2 Prescribed Burning Baseline Inventory................................................................................................................... 9

2.3 Wildland Fire Use Baseline Inventory................................................................................................................... 11

2.4 Agricultural Burning Baseline Inventory................................................................................................................ 12

2.5 Non-Federal Rangeland Prescribed Burning Baseline Inventory ......................................................................... 16

2.6 Baseline Inventory Results and Comparison to Phase II...................................................................................... 17

2.7 Base Control Case Inventory................................................................................................................................ 21

3 PROJECTION (2018) FIRE EMISSION INVENTORIES ............................................................................................. 27

3.1 Prescribed Burning Projection Inventory .............................................................................................................. 28

3.1.1 Prototype or “Stem Cell” Events.................................................................................................................... 30

3.2 Wildfire and Wildland Fire Use Projection Inventory............................................................................................. 31

3.3 Agricultural Burning Projection Inventory.............................................................................................................. 33

3.4 Non-Federal Rangeland Prescribed Burning Projection Inventory....................................................................... 37

3.5 Air Quality Planning Suites ................................................................................................................................... 38

3.6 Projection Inventory Results and Comparison to Baseline................................................................................... 39

Tables 

Table 1: Summary of Phase II EI and Baseline EI Development..................................................................................... 6

Table 2: Summary of Baseline Development and Phase II Comparison Methods ........................................................ 18

Table 3: ERFs (percent PM2.5 emissions averted) for Seasonal Suites of ERTs........................................................... 23

Table 4: Summary of 2018 Projection Scalars for the Less, Likely, and More Scenarios.............................................. 27

Table 5: Summary of Air Quality Planning Suites .......................................................................................................... 39
WRAP Fire Ph3-4 EI Report_20070515.doc iii

CONTENTS - continued Page

Figures 

Figure ES-1: Baseline and Projection Emission Inventory Results...............................................................................E-2

Figure 1: Baseline Scalars for Wildfire and Comparison of WRAP Phase II to Fed-5 Database ................................. 7

Figure 2: Potential Range of Wildfire Activity and Emissions Estimated From the Baseline Period Fed-5 Data and 

Comparison to Baseline Activity and Emissions ........................................................................................... 8

Figure 3: Potential Range of Wildfire Activity by State Estimated From the Baseline Period Fed-5 Data and 

Comparison to Baseline Activity.................................................................................................................... 9

Figure 4: Baseline Scalars for Prescribed Burning and Comparison of WRAP Phase II to SIT Database ................ 10

Figure 5: Baseline Scalars for WFU and Comparison of WRAP Phase II to SIT Database....................................... 12

Figure 6: Comparison of WRAP Phase II Burned Agricultural Acres to NASS Harvested Agricultural Acres............ 13

Figure 7: Baseline Acres Harvested by Crop, County, and Month for Nevada .......................................................... 15

Figure 8: Baseline Agricultural Acres Burned and Number of Burn Events by Crop and County for Nevada............ 15

Figure 9: Comparison of WRAP Phase II Burned NFR Acres to NRI Existing NFR Acres......................................... 17

Figure 10: Comparison of WRAP Phase II to Phase III Emission Inventories by Fire Type......................................... 18

Figure 11: Comparison of WRAP Phase II to Phase III Wildfire Inventory by State..................................................... 19

Figure 12: Comparison of WRAP Phase II to Phase III Prescribed Burning Inventory by State .................................. 19

Figure 13: Comparison of WRAP Phase II to Phase III WFU Inventory by State......................................................... 20

Figure 14: Comparison of WRAP Phase II to Phase III Agricultural Burning Inventory by State ................................. 20

Figure 15: Comparison of WRAP Phase II to Phase III Non-Federal Rangeland Burning Inventory by State ............. 21

Figure 16: WRAP Phase III Base Control Case: Wildland Prescribed Burning PM2.5 Emissions by State With 

Emissions Averted Due to the Implementation of ERTs ............................................................................. 25

Figure 17: WRAP Phase III Base Control Case: Wildland Prescribed Burning PM2.5 Emissions and Acres by 

Vegetation Category With Emissions Averted Due to the Implementation of ERTs ................................... 26

Figure 18: WRAP Phase III Base Case Control: Agricultural Burning PM2.5 Emissions by State With Emissions 

Averted Due to the Implementation of ERTs............................................................................................... 26

Figure 19: WRAP Phase IV 2018 Projection Inventory: Prescribed Burning PM2.5 Emissions and Acres by State for 

Each Scenario ............................................................................................................................................. 29

Figure 20: WRAP Phase IV 2018 Projection Inventory: Prescribed Burning PM2.5 Emissions and Acres by Scenario 

With Emissions Averted Due to the Implementation of ERTs ..................................................................... 29

Figure 21: Comparison of WRAP Phase III to Phase IV Wildfire and Wildland Fire Use Acres and PM2.5 .................. 32

Figure 22: Comparison of WRAP Phase III to Phase IV Wildfire and Wildland Fire Use Acres and PM2.5 by State .... 32

Figure 23: Agricultural Burning Baseline Versus 2018 Projection Inventory ................................................................ 36

Figure 24: Agricultural Burning Projection EI Acres Burned, Tons PM2.5 Emitted, and Emission Averted from the 

Application of ERTs..................................................................................................................................... 37

Figure 25: Comparison of WRAP Phase III to Phase IV 2018 Non-Federal Rangeland Burning Likely Inventory by 

State............................................................................................................................................................ 38

Figure 26: Summary of Phase IV Projection Inventory Air Quality Planning Suites ..................................................... 40
WRAP Fire Ph3-4 EI Report_20070515.doc iv

 CONTENTS - continued Page

Appendices 

Appendix A: Technical Methodologies Used to Create Event-Based Fire Records in the 2002 Phase II Fire Emission 

 Inventories

Appendix B: Uncertainty Analysis and Exceptions for WRAP Phase IV Fire Event Projection Methodology

Appendix C: Reviewer Comments and Corrective Actions

Appendix D: EPA Proposed SCC Codes
WRAP Fire Ph3-4 EI Report_20070515.doc E-1

SECTION 

EXECUTIVE SUMMARY 

The Fire Emissions Joint Forum (FEJF) of the Western Regional Air Partnership (WRAP), through 

a contract issued by the Western Governors Association (WGA) to Air Sciences Inc. and EC/R 

Incorporated, has prepared “Phase III” baseline period (2000-2004) and “Phase IV” projection 

year (2018) fire emission inventories. This document is a summary of the technical methodology, 

activity data, and calculated emissions for baseline and projection inventories of wildfire, 

prescribed burning, wildland fire use (WFU), agricultural burning, and non-federal prescribed 

rangeland burning (NFR). 

The purpose of this project (“Development of 2000-04 Baseline Period and 2018 Projection Year 

Emissions Inventories”) is to develop fire emissions inventories (EIs) for regional haze planning 

purposes. The inventories are intended to be representative of fire emissions during the Regional 

Haze Rule’s (Rule) baseline monitoring period (2000-04) and to describe potential fire activity 

scenarios for the Rule’s initial projection year of 2018. Projection inventories were prepared for 

“less,” “likely,” and “more” activity scenarios for each fire type. Then individual EI files for each 

fire type were combined to form three distinct air quality planning suites for fire emissions: 

• Base-case – Likely projection activity scenarios for all fire types. 

• Climate Conditions/Resource Limited – More occurrences of wildfire and Wildland 

Fire Use with less application of prescribed burning in wildlands. 

• Max-Application of Prescribed Fire – Highest level of application of prescribed burning 

with likely activity levels for all other fire types. 

The EI data files and air quality planning suites produced for this project are to be used for 

regional dispersion modeling analyses and to populate the WRAP’s Emissions Data Management 

System (EDMS). In addition, the deliverables for this project are intended to provide necessary, 

timely, and sufficient documentation for use by WRAP members for use in assessing the need, 

structure, and scope of fire and smoke emissions management programs in the implementation 

plans due by the end of 2007. Figure ES-1 and its associated data table present a summary of the 

results of the baseline and projection emission inventories. 
WRAP Fire Ph3-4 EI Report_20070515.doc E-2

Figure ES-1: Baseline and Projection Emission Inventory Results 

The methodologies for creating the baseline inventories for each fire source, along with a 

presentation of the results of the baseline inventory work appear in Section 2. The methodologies 

and results for the projection inventories are presented in Section 3. 

WRAP Phase IV 2018 Fire Projection EI 

Source Activity Scenarios Grouped into Air Quality Planning Suites

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

5,000,000

Acres

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

Tons PM2.5

Prescribed Acres 669,348 1,959,700 966,191 3,704,327

WFU Acres 153,697 2,311,067 4,703,922 2,311,067

Wildfire Acres 4,517,818 2,263,069 2,263,069 2,263,069

Agricultural Acres 2,164,166 1,730,333 1,730,333 1,730,333

NF Rangeland Acres 1,042,003 1,257,004 1,257,004 1,257,004

Prescribed PM2.5 59,635 219,298 110,091 427,028

WFU PM2.5 41,171 526,636 1,155,633 526,636

Wildfire PM2.5 971,453 480,269 480,269 480,269

Agricultural PM2.5" 34,590 29,591 29,591 29,591

NF Rangeland PM2.5 15,454 18,643 18,643 18,643

Baseline Control Case Base-case Climate conditions/

resource limited Max-App of Rx Fire

Less

More

More

More

("Likely" activity and emission scenario choosen unless otherwise noted)
WRAP Fire Ph3-4 EI Report_20070515.doc 1

SECTION 1 

INTRODUCTION 

The Fire Emissions Joint Forum (FEJF) of the Western Regional Air Partnership (WRAP), through 

a contract issued by the Western Governors Association (WGA) to Air Sciences Inc. and EC/R 

Incorporated, has prepared “Phase III” baseline period (2000-2004) and “Phase IV” projection 

year (2018) fire emission inventories. This document is a summary of the technical methodology, 

activity data, and calculated emissions for baseline and projection inventories of wildfire, 

prescribed burning, wildland fire use (WFU), agricultural burning, and non-federal prescribed 

rangeland burning (NFR). 

The purpose of this project (“Development of 2000-04 Baseline Period and 2018 Projection Year 

Emissions Inventories”) is to develop fire emissions inventories (EIs) for regional haze planning 

purposes. These wildfire, wildland fire use, prescribed fire, rangeland fire, and agricultural fire 

EIs will be representative of fire emissions during the Regional Haze Rule’s (Rule) baseline 

monitoring period (2000-04) and describe potential inventory scenarios for the Rule’s initial 

projection year of 2018. The objective is to build event-based inventories comprised of 

realistically sized, placed, and timed fires that add up to equal activity targets that have been 

determined to be representative of the baseline and projection periods. The source of the fire 

events used to populate the baseline and projection inventories are the fire event records from the 

WRAP’s Phase II (historical 2002) fire emission inventory. 

In order to gather data and develop appropriate assessment and analysis techniques, Air Sciences 

directed two Phase III/IV Technical Workshops (Workshops) in August and November 2005. 

The Workshops were attended by federal land managers, Smoke Management Program 

personnel, and any other stakeholders that wished to participate. The primary purpose of the 

Workshops was to agree on the baseline and activity targets for each fire type (wildfire, Wildland 

Fire Use, prescribed burning, agricultural burning, and non-federal rangeland burning). In the 

Workshops, participants were presented Strawman approaches for their consideration and then 

participants and the contractors would work together to refine and approve the technical 

approaches to be employed to build the baseline and projection inventories. The details of the 

Workshop #1 (August 2005) can be reviewed at 

http://www.wrapair.org/forums/fejf/meetings/050810fc/index.html and the details for 

Workshop #2 (November 2005) can be reviewed at 

http://www.wrapair.org/forums/fejf/meetings/051101m/index.html. 

Results from prior and ongoing FEJF emissions inventory work, air quality sensitivity modeling 

results, and source attribution analyses will provide additional information on the appropriate 

considerations and framework to conduct the preparation of the baseline and projection years’ 

fire EIs. 
WRAP Fire Ph3-4 EI Report_20070515.doc 2

The EI files for this project are expected to serve as input to the WRAP Emissions Data 

Management System (EDMS). The EDMS is expected to be capable of producing output EI files 

that can be used in regional modeling analyses to quantify the air quality improvements 

associated with emissions reductions due to smoke management programs being implemented 

by WRAP states and Tribes. In addition, the deliverables for this project are intended to provide 

necessary, timely, and sufficient documentation for use by WRAP members for use in assessing 

the need, structure, and scope of fire and smoke emissions management programs in the 

implementation plans due by the end of 2007. 

For regional dispersion modeling purposes, the baseline and projection inventory files have been 

delivered in SMOKE Model Format (PT/IDA). For emission inventory purposes, the baseline 

and projection inventory files have been delivered in database file (DBF) format. 

There are many technical methodologies that are common to the development of the Phase II 

events that are used to build both the baseline and the projection fire emission inventories. These 

methodologies are described in detail in the documentation for previously completed 

WRAP/FEJF projects. These projects are listed below and the posted documentation is available 

on the FEJF project pages of the WRAP’s website (url’s are provided in parentheses). In addition, 

for ease of reference as reviewers read this document, descriptions of several critical technical 

methodologies are included in this report in Appendix X. 

• WRAP Phase I Fire Emission Inventory. 

(http://www.wrapair.org/forums/fejf/tasks/FEJFtask7PhaseI.html) 

• WRAP 2002 Phase II Fire Emission Inventory. 

(http://www.wrapair.org/forums/fejf/tasks/FEJFtask7PhaseII.html) 

1.1 Fire Inventory Calculation Tool 

Air Sciences Inc. developed an EXCEL-based spreadsheet tool to generate the nominal (i.e., not 

actual) fire event databases for the baseline and projection inventories. The essential functions of 

the Calculation Tool include: 

• Store Phase II fire events (actual fire events) as “seed” data to be used to build the 

nominal, event-based inventories. 

• Accommodate entry of state- and agency-specific fire activity targets (in acres) for the 

inventory planning years (Phase III – 2000-2004 representative year; Phase IV – 2018). 

• Perform database processing tasks that populate the nominal fire inventory with seed 

data until the state- and agency-specific fire activity targets are reached. 
WRAP Fire Ph3-4 EI Report_20070515.doc 3

The Calculation Tool, while developed to prepare the baseline and projection inventories for this 

project, will be modified and made available to WRAP states and Tribes to facilitate preparation 

of custom nominal inventories of prescribed fire. It is anticipated that the Calculation Tool will 

be available to states and Tribes in the spring of 2007 as a technical tool on the WRAP’s webbased Technical Support System. 

1.2 Quality Assurance/Quality Control 

The Quality Assurance/Quality Control (QA/QC) Plan was implemented as specified in 

Appendix A of the project Work Plan (Air Sciences and EC/R, August 2005). Specific QA/QC 

procedures are described in the text of this report. In addition, changes to the inventories that 

arose out of the implementation of QA/QC procedures are presented and quantified in the text 

of this report. 

1.3 National Inventory Format (NIF) Files 

Air Sciences, in consultation with the FEJF, have concluded that NIF files for the baseline and the 

projected fire inventories will have limited utility for WRAP states and tribes. This finding is 

based on the fact that the baseline and projection fire inventories are nominal (i.e., not actual) 

inventories and files in NIF format have historically been used for States and Tribes to fulfill 

federal requirements for periodic reporting of actual emissions to the National Emission 

Inventory (NEI). Therefore, the NIF files will not be prepared. Air Sciences will retain the scripts 

to create the NIF files in the future if required by the WRAP. 
WRAP Fire Ph3-4 EI Report_20070515.doc 4

SECTION 2 

BASELINE (2000 – 04) FIRE EMISSION INVENTORIES 

Baseline period (2000-04) inventories were built based upon the FEJF's Phase II (historical 2002) 

inventories for wildfire, wildland fire use, prescribed burning, agricultural burning, and nonfederal rangeland burning completed in 2005 by the FEJF (Air Sciences, July 2005 

http://www.wrapair.org/forums/fejf/tasks/FEJFtask7PhaseII.html). 

The fundamental steps to build the baseline fire inventory were: 

1. Gather relevant activity data to determine emissions estimates; and 

2. Apply various assessment and analysis techniques to determine if and where fire 

emissions for the 2000-04 period are different from the WRAP Phase II “actual 2002” 

inventory report and EI products at various appropriate geographic scales, using 

statistical significance tests. 

The project team has prepared a 2000-04 baseline period EI similar in scope and scale to the Phase 

II 2002 fire EI. The process for preparing the baseline period EI included an assessment of 

whether the temporal and spatial distribution of the Phase II 2002 EIs for all types of fire can be 

preserved or can reasonably be changed with technical justification. These analyses were 

presented to the FEJF prior to building the baseline period EI. For WRAP region jurisdictions 

with Smoke Management Programs (SMP), data were also gathered to allow the calculation of 

the benefit of applying Emissions Reduction Techniques (ERTs) in each jurisdiction’s SMP. 

Wildfire, prescribed burning, and WFU baseline emission inventories were each created by 

"scaling" the respective Phase II inventory up or down based on an analysis of independent 

activity data across the baseline period. Agricultural burning and non-federal prescribed 

rangeland burning inventories for Phase II were considered to be representative of annual 

activity during the baseline period. Therefore, the Phase II EIs for agricultural burning and nonfederal rangeland burning were used as is as the baseline inventories. 

2.1 Wildfire Baseline Inventory 

A single scenario for wildfire activity was developed that represented wildfire in the baseline 

(2000-04). All events in the wildfire inventory were categorized as "natural" per the WRAP's Fire 

Categorization Policy. 

The WRAP's Phase II wildfire inventory for 2002 (which has been reviewed by state, Tribal, and 

federal agencies through the Phase II QC process) served as the starting place for the wildfire 

baseline inventory. The Phase II wildfire inventory was scaled up or down on a state-by-state 

basis to meet computed baseline levels per the following steps: 
WRAP Fire Ph3-4 EI Report_20070515.doc 5

1. Air Sciences obtained the Federal Fire History data (Fed-5 data) compiled by the 

Geospatial Task Group of the National Wildfire Coordinating Group 

(ftp://ftp.nifc.gov/pub/FireHistoryData/). Fed-5 data is available for the baseline 

years 2000-2003 but data for 2004 was not compiled at the time of the preparation of 

the baseline inventories. 

2. Developed a summary table of acres of wildfire by state by year. 

3. For each state, calculated the mean number of annual wildfire acres over the baseline 

period 2000 - 2003. This is the average annual activity for the baseline period according 

to the Fed-5 data. 

4. For each state, calculated the difference in Phase II wildfire acres and Fed-5 wildfire 

acres strictly for year 2002. This difference is intended to emphasize the more resolved 

data collection and quality control activities in the WRAP Phase II activity data set. 

The goal for building the baseline inventory for wildfire is to preserve this difference 

when considering the average annual activity derived from the Fed-5 data. 

5. For each state, the Phase II versus Fed-5 difference for 2002 was added to the mean of 

the Fed-5 wildfire acres. The result represents the "baseline target" in acres for each 

state. The baseline target divided by the Phase II activity acres is the "baseline scalar" 

for a state. See Equations 1 and 2. 

 Baseline target = [Phase II 2002 – Fed-5 2002] + Average (Fed-5 2000 thru 2003) (1) 

 Baseline scalar = Baseline Target / Phase II 2002 (2) 

Phase II wildfire events (acres/day for each fire event) were used to build the baseline wildfire 

inventory on a state-by-state basis (see Figure 1 on page 7). For states with a baseline scalar of 

less than one, then Phase II events were randomly removed from the Phase II data set for that 

state until the baseline target in acres was met. If the scalar for a state was greater than one, then 

wildfire events from the Phase II inventory for that state were randomly repeated until the 

baseline target was met. Wildfire events added or removed were randomized but fire days 

comprising an event were kept together. In this way the concept of multi-day events was 

preserved in the baseline inventory. Similarly, smoldering records were carried over to the 

baseline inventory (or excluded) according to the outcome of its parent flaming-day record. 

In the instances where records from the Phase II inventory were added to the baseline inventory 

in order to reach the baseline targets, data processing steps were implemented: 

• Each event added to the baseline inventory was assigned a random date within the 

month of occurrence of the original Phase II record. 

• All other attributes of the fire event were cloned including acres consumed and tons of 

each pollutant emitted. The location (latitude and longitude) of the event was not 
WRAP Fire Ph3-4 EI Report_20070515.doc 6

changed because when the emissions input data are processed by the WRAP’s 

Regional Modeling Center, each emissions event is associated with the 36 km by 36 km 

grid cell (i.e., the latitude and longitude of the event is not preserved in the results of 

the model runs). Therefore, the Emissions Task Team of the FEJF determined to not 

change the latitude and longitude of the event going into the baseline inventory so that 

the emissions from the event would appear in the same RMC grid cell. 

Scaling the Phase II inventory up or down in this manner created a baseline emission inventory 

with the desired change in emissions magnitude and retention of the overall activity statistics 

(seasonality, location, fuel types, etc.) of an “actual” year of fire events (the 2002 Phase II 

inventory). Table 1 presents the WRAP-wide statistics for the baseline inventory (as well as a the 

Phase II fire statistics for comparison purposes). 

Table 1: Summary of Phase II EI and Baseline EI Development 

Fire Source 

Baseline 

Adaptation 

From Phase II 

Phase II 

Acres 

Burned 

Phase II 

Tons PM2.5 

Emitted 

Baseline 

Acres Burned 

Baseline 

Tons PM2.5 

Emitted 

Wildfire Scaled by state 5,276,485 1,489,886 4,517,818 971,453 

Prescribed Burning Scaled by state 649,044 71,421 669,348 72,218 

WFU Scaled by state 201,548 81,505 153,697 41,171 

Agricultural As is + NV 2,162,836 34,571 2,164,166 34,571 

NFR As is 1,042,003 15,454 1,042,003 15,454 

Total 9,331,917 1,692,838 8,547,031 1,134,868 

Figure 1 and its associated data table show the Phase II wildfire acreage compared to Fed-5 

wildfire acreage and the baseline target acreage and lists the scalars used to reach the baseline 

targets. 
WRAP Fire Ph3-4 EI Report_20070515.doc 7

Figure 1: Baseline Scalars for Wildfire and Comparison of WRAP Phase II to Fed-5 Database 

For Alaska and Utah, the 2002 Fed-5 wildfire acreages were at least 1.5 times greater than the 

2002 Phase II acreages. Using the 2002 Fed-5 acres in Equation 1 resulted in a baseline target that 

was less than any individual year of Fed-5 data for the respective state. Upon investigation of the 

suspected source of the differences in activity levels between the Phase II EI and the Fed-5 data, 

Air Sciences concluded that the discrepancy is likely to be due to the more rigorous data 

collection and quality control techniques implemented in the WRAP Phase II project. 

Implementing the scalar development techniques that were applied to all other states would have 

produced unreasonably low baseline targets for Alaska and Utah. Therefore, Air Sciences, with 

concurrence from the Emissions Task Team of the FEJF, elected to use the average of the Fed-5 

acres as the baseline targets for Alaska and Utah. 

In addition to the "static" baseline inventory for wildfire, a potential range of emissions (from low 

to high) for wildfire was estimated for the baseline period based on Fed-5 data. The low and high 

range of wildfire activity was determined from minimum and maximum years of the annual 

WRAP-wide Fed-5 total acres burned. The low range year of activity was Fed-5 2001 and the 

high range year was Fed-5 2002. The low and high range of emissions was estimated from the 

Fed-5 2001 and 2002 activity totals by scaling Baseline PM2.5 up or down by the difference 

between Baseline total acres and the Fed-5 low and high year total acres. As shown in Figure 2, 

Baseline Scalars for Wildfire: WRAP Phase II vs. "Fed5 database"

0

250,000

500,000

750,000

1,000,000

1,250,000

Acres

2000 Fed 5 767,707 68,854 323,205 126,301 1,677,150 945,541 9,238 340,445 594,609 350,385 373,416 233,577 99,167 367,077

2001 Fed 5 218,114 21,081 411,334 15,552 190,009 230,694 5,481 32,674 444,329 370,971 57,149 69,382 255,136 90,450

2002 Fed 5 2,660,393 597,932 596,550 404,025 85,614 186,403 39,636 260,990 42,714 1,017,949 91,576 406,698 81,031 156,518

2003 Fed 5 583,214 333,573 1,155,525 45,537 346,840 903,556 5,286 183,991 17,793 158,568 45,992 105,564 145,727 108,374

Phase II Wildfire 1,790,533 555,873 510,140 412,697 77,678 112,413 83,599 247,243 56,218 921,515 78,384 212,853 89,854 127,486

Baseline 1,057,357 213,301 535,244 156,525 566,967 492,559 58,874 190,778 288,365 378,034 128,841 203,805 154,088 151,573

Scalar 0.6 0.4 1.0 0.4 7.3 4.4 0.7 0.8 5.1 0.4 1.6 1.0 1.7 1.2

Average Fed5 1,057,357 255,360 621,653 147,854 574,903 566,549 14,910 204,525 274,861 474,468 142,033 203,805 145,265 180,605

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 8

the low range of emissions was estimated as 512,100 tons PM2.5 and the high range as 1,407,100 

tons PM2.5. 

Figure 2: Potential Range of Wildfire Activity and Emissions Estimated From the Baseline Period 

Fed-5 Data and Comparison to Baseline Activity and Emissions 

Figure 3 shows the potential range of wildfire activity by state. On a WRAP-wide basis, 2001 was 

the low range year and 2002 was the high range year. However, for any individual state, any 

year during the baseline period can have the lowest or highest acres burned. (For example, in 

Idaho, 2002 was the lowest year and 2000 was the highest year.) The totals shown are the totals 

for each year. Figure 3 shows the extremes within each state. Note that for the range of 

emissions estimation, the 2002 emissions do not match the WRAP Phase II 2002 emission 

inventory because they are estimated from Fed-5 data, not calculated from individual events. 

Potential Range of Wildfire Activity (acres) and Emissions (PM2.5) 

Estimated from Baseline Period Fed-5 Data

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

Acres or Tons

Acres 2,412,400 4,576,300 6,628,000

Tons PM2.5 512,100 971,500 1,407,100 

Low Range (2001 Fed5) Baseline Wildfire High Range (2002 Fed5)
WRAP Fire Ph3-4 EI Report_20070515.doc 9

Figure 3: Potential Range of Wildfire Activity by State Estimated From the Baseline Period Fed-5 

Data and Comparison to Baseline Activity 

2.2 Prescribed Burning Baseline Inventory 

The WRAP's Phase II prescribed fire inventory for 2002 (which has been reviewed by state, 

Tribal, and federal agencies through the Phase II QC process) served as the starting place for the 

prescribed fire baseline inventory. The baseline inventory for prescribed burning was built stateby-state using methods similar to the process implemented to develop the wildfire baseline 

inventory. The primary difference between the two methods is that the average annual activity 

for the baseline period (2000 – 2004) for prescribed burning was obtained from the Interagency 

Situation Report (SIT) Program SIT/ICS-209 reports (not the Fed-5 data used for wildfire). 

The Interagency Situation Report (SIT) Program is a web-based application that captures incident 

activity and resource status information in summary form intended for use by land managers. 

SIT reports for prescribed and wildland fires are submitted by Dispatch Offices on a daily basis 

May through October. Reports are also submitted November through April if wildland fires are 

active or if fire danger is "very high" or "extreme." The SIT Program uses incident information 

from the ICS-209 Program. Incident Status Summaries (ICS-209) are submitted to the Geographic 

Area Coordination Centers (GACCs) and are used to report significant fire events on lands under 

federal protection or federal ownership. Lands administered by states and other federal 

cooperators may also report to the ICS-209 Program. Significant events are classified as large 

Potential Range of Wildfire Activity (acres)

by State from Baseline Period Fed-5 Data

0

400,000

800,000

1,200,000

1,600,000

2,000,000

Acres

Baseline 1,057,357 213,301 535,244 156,525 566,967 492,559 58,874 190,778 288,365 378,034 128,841 203,805 154,088 151,573 4,576,311

2000 Fed 5 767,707 68,854 323,205 126,301 1,677,150 945,541 9,238 340,445 594,609 350,385 373,416 233,577 99,167 367,077 6,276,673

2001 Fed 5 218,114 21,081 411,334 15,552 190,009 230,694 5,481 32,674 444,329 370,971 57,149 69,382 255,136 90,450 2,412,356

2002 Fed 5 2,660,393 597,932 596,550 404,025 85,614 186,403 39,636 260,990 42,714 1,017,949 91,576 406,698 81,031 156,518 6,628,028

2003 Fed 5 583,214 333,573 1,155,525 45,537 346,840 903,556 5,286 183,991 17,793 158,568 45,992 105,564 145,727 108,374 4,139,540

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY TOTAL
WRAP Fire Ph3-4 EI Report_20070515.doc 10

wildfires or WFU events that are 100 acres or larger in timber fuel types, 300 acres or larger in 

grass or brush fuel types, or events when a Type 1 or 2 Incident Management Team is assigned. 

The ICS-209 is submitted by the agency that has protection responsibility for the incident 

regardless of who administers the land. GACCs are responsible for ensuring that reports are 

complete and accurate. The SIT data was the most appropriate data source available at the time 

that this project was performed for determining average annual activity during the baseline 

period because the SIT and 209 Programs "capture incident activity" as opposed to cataloging 

planned activity. 

SIT acres were filtered for prescribed burning activity tallied in the "RXACRES" field. The 

baseline target from prescribed burning was calculated as indicated in Equations 3 and 4. 

Baseline target = [Phase II 2002 – SIT 2002] + Average (SIT 2000 thru 2004) (3) 

Baseline scalar = Baseline target / Phase II 2002 (4) 

Phase II prescribed burning events were used to assemble the scaled baseline inventory in the 

same manner as for wildfire. Each event in the Phase II prescribed fire inventory has been 

categorized as "natural" or "anthropogenic" according the categorization method approved by the 

ETT and the FEJF. This categorization carried through to the baseline inventory. Figure 4 shows 

the state-by-state Phase II prescribed burning acreage compared to SIT prescribed burning 

acreage, as well as the baseline target acreage and the scalars used to reach baseline. 

Figure 4: Baseline Scalars for Prescribed Burning and Comparison of WRAP Phase II to SIT 

Database 

Baseline Scalars for Prescribed Burning: WRAP Phase II vs. SIT

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Acres

2000 SIT 0 24,393 41,598 9,235 13,433 12,137 3,506 26,702 2,540 24,427 8,561 3,275 9,080 2,363

2001 SIT 2,280 50,726 28,146 19,769 14,454 12,143 13,071 23,734 11,032 86,951 4,156 35,198 10,430 1,936

2002 SIT 1,560 44,347 73,962 8,762 38,049 15,022 17,269 7,989 1,441 72,005 3,636 14,117 12,624 3,179

2003 SIT 1,555 69,405 58,840 15,398 38,760 16,297 4,235 22,384 3,584 83,260 264 17,886 22,514 23,390

2004 SIT 58,231 55,310 76,586 49,602 46,158 34,802 21,099 18,393 3,630 127,260 10,056 18,840 32,521 14,802

Phase II Rx 1,108 103,619 86,785 17,425 89,477 77,419 26,826 25,292 5,659 129,290 8,811 14,531 41,196 21,605

Baseline 1,346 108,108 68,649 29,216 81,599 80,478 21,393 37,143 8,664 136,066 10,510 18,278 46,006 27,560

Scalar 1.2 1.0 0.8 1.7 0.9 1.0 0.8 1.5 1.5 1.1 1.2 1.3 1.1 1.3

Average SIT 1,798 48,836 55,826 20,553 30,171 18,080 11,836 19,840 4,445 78,781 5,335 17,863 17,434 9,134

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 11

For Alaska, review of the 2000 and 2004 SIT acreage during the Workshops by the participants 

and the contractor resulted in the conclusion that the 2000 and 2004 SIT acreage data were not 

accurate. Therefore, only 2001, 2002, and 2003 SIT data were used to develop the baseline scalar 

for Alaska. 

2.3 Wildland Fire Use Baseline Inventory 

The WRAP's Phase II WFU inventory for 2002 (which has been reviewed by state, Tribal, and 

federal agencies through the Phase II QC process) served as the starting place for the WFU 

baseline inventory. The baseline inventory for WFU was built state-by-state analogous to the 

method used for prescribed burning, also using the SIT database. In this case, the SIT data was 

filtered for wildland fire use acres identified as "WFURBACRES." 

The following special rules were necessary to account for incomplete data in either the Phase II or 

SIT database. 

• The average of the SIT (2000-2004) acres was used as the baseline target if: 

o The Phase II acres were fewer than the SIT 2002 acres (presumed underreporting in 

Phase II for the affected state). 

o Either Phase II or SIT 2002 has zero acres reported. 

• In both North and South Dakota, no WFU acres were recorded in the Phase II 

inventory or in any year of the SIT data, and therefore baseline targets were zero. 

• In Oregon and Washington, the WFU acres burned were negligible (less than 500 acres 

annually) and therefore the baseline inventories would have been difficult to precisely 

produce through the standard of using random events to build the inventory until the 

baseline targets are reached. Therefore, the baseline targets for Oregon and 

Washington were set to zero. 

Phase II WFU events were used to assemble the scaled baseline inventory in the same manner as 

for prescribed burning: Phase II WFU events were added to the inventory or dropped to meet 

WFU baseline targets. For states that had a WFU-baseline/Phase II scalar greater than 1.0, new 

WFU events were created from Phase II wildfire events. (This is because there were so few WFU 

events in the Phase II inventory that building the baseline WFU inventory from Phase II WFU 

events would have resulted in an unrealistically homogeneous set of events in the baseline WFU 

inventory). On a state-by-state basis, events from the original Phase II wildfire database were 

randomly chosen until the baseline target was met. The dates for these adapted wildfire events 

were shifted to the subsequent month because an analysis of WFU and wildfire activity by month 

in the SIT database showed that the WFU "season" lagged behind wildfire by about one month. 
WRAP Fire Ph3-4 EI Report_20070515.doc 12

Each event in the baseline WFU inventory was categorized as "natural" per the categorization 

method approved by the ETT and the FEJF. Figure 5 shows the Phase II WFU acreage compared 

to SIT WFU acreage and the baseline target acreage, along with the scalars used to reach baseline. 

Figure 5: Baseline Scalars for WFU and Comparison of WRAP Phase II to SIT Database 

Baseline Scalars for WFU: WRAP Phase II vs. SIT

0

10,000

20,000

30,000

40,000

50,000

60,000

Acres

2000 SIT 0 1,175 756 1 19 6,001 0 305 0 0 0 861 0 400

2001 SIT 0 2,717 11,490 4,824 11,049 34,746 0 773 7,566 1 0 530 2 4,196

2002 SIT 0 0 2,421 15,523 5,552 1,155 0 1,643 852 1 0 193 11 5,137

2003 SIT 0 754 27,164 1,563 28,814 56,616 0 83,294 2 151 0 587 1 6,380

2004 SIT 55,021 1,172 5,030 4,707 5,177 433 0 859 494 1,112 0 12,529 27 4

Phase II WFU 159,554 0 4,051 22,852 3,543 25 0 4,759 0 0 0 545 0 6,220

Baseline 55,021 1,455 11,002 12,652 10,122 19,790 0 20,491 2,229 0 0 3,292 0 4,306

Scalar 0.3 0.0 2.7 0.6 2.9 791.6 0.0 4.3 0.0 0.0 0.0 6.0 0.0 0.7

Average SIT 55,021 1,455 9,372 5,324 10,122 19,790 0 17,375 2,229 316 0 2,940 10 3,223

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY

2.4 Agricultural Burning Baseline Inventory 

The WRAP's Phase II agricultural burning inventory for 2002 (which has been reviewed by state 

and Tribal agencies through the Phase II QC process) served as the starting place for the 

agricultural burning baseline inventory. The Phase II agricultural burning inventory was 

comprised of a combination of event-based and gap-filled data (i.e., for states with minimal 

agricultural burning data but where agricultural burning activities are known to occur, 

agricultural burning events derived from summary statistics such as crop production and cropspecific percentage of acres burned data were allocated to these states. Given the nature of the 

burning activity data (comprised of actual events and gap-filled events), the Phase II inventory 

was considered to be representative of any year during the baseline period. 

Air Sciences performed a "reality check" of agricultural burning activity in the Phase II inventory 

and performed additional and essential gap-filling to develop the final baseline inventory for 

agriculture burning. Air Sciences acquired acres harvested statistics from the 2002 Census of 

Agriculture published by the USDA – National Agricultural Statistics Service (NASS). This 
WRAP Fire Ph3-4 EI Report_20070515.doc 13

analysis was for field crops and excluded "forage". The total acres burned by state in the Phase II 

inventory was divided by the acres harvested by state according to NASS to arrive at a "percent 

burned" statistic. Figure 6 shows the comparison of Phase II acres burned to NASS acres 

harvested, as well as the percent burned statistic. 

Figure 6: Comparison of WRAP Phase II Burned Agricultural Acres to NASS Harvested 

Agricultural Acres 

Montana, South Dakota and Nevada had the lowest percent burned statistics and their Phase II 

activity was therefore scrutinized in detail. Air Sciences reviewed correspondence and data 

augmentation previously performed under the Phase II contract. The Montana Department of 

Environmental Quality had submitted data during the Phase II "QC process" to bring the activity 

levels to their satisfaction. Likewise, South Dakota Department of Environment and Natural 

Resources had participated in the Phase II QC Process and provided activities levels and 

knowledge of burning practices. Even though Montana and South Dakota had low percent 

burned statistics relative to other WRAP states, the investigation determined the inventory was 

reasonable. Phase II activity in the state of Nevada was initially zero acres and this was identified 

as requiring essential gap-filling. 

Chet Sergent at the Nevada Division of Environmental Protection provided annual acres 

harvested of field crops for 2002 (using NASS as his source), the predominate counties in which 

agricultural burning occurs, and the typical size of an agricultural burn in each county. The 

Agricultural:

Phase II (acres burned) vs. NASS (acres harvested)

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

16,000,000

Acres (Burned or Harvested)

0%

2%

4%

6%

8%

10%

12%

14%

16%

Percent Burned

Sum of NASS acres 612,435 6,552,232 3,007,856 2,694,871 5,966,349 15,441,302 502,582 26,599 1,243,874 10,083,013 221,085 3,574,304 336,002

Sum of Phase II acres 16,203 727,641 38,231 292,348 8,890 211,932 21,180 1,330 129,781 5,018 16,684 656,705 38,223

Percent 2.65% 11.11% 1.27% 10.85% 0.15% 1.37% 4.21% 5.00% 10.43% 0.05% 7.55% 18.37% 11.38%

AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 14

average annual harvest activity by crop for the baseline period was also obtained, where 

available, from NASS, and merged with the information provided by Mr. Sergent to determine 

the total acres harvested. This value was then converted to acres burned and subsequently 

allocated to individual fire events. Mr. Sergent determined that five-percent of the NASS harvest 

acres was a reasonable assumption to estimate agricultural burning activity for Nevada. This 

assumption was used in Figure 6. The crops that were presumed to be burned were alfalfa 

(grown for seed), barley, corn (for silage), oats, spring wheat, and winter wheat. Annual acres 

harvested per crop were allocated to each "major player" county based on NASS reporting. 

Those annual county figures were then allocated to monthly totals based on Nevada Department 

of Environmental Protection general rules. Figure 7 shows the acres harvested by crop by county 

by month in Nevada. The acres burned (shown in Figure 8) were calculated from the acres 

harvested using the 5% burning rate provided by Mr. Sergent. The acres of burning by crop by 

county by month were further broken down into typically sized (10 acres or the remainder 

thereof) events and assigned to a random day in the month. "Blackout days" per the Phase II 

agricultural emission inventory allocation, were observed. (For details, please see the report 

“Integrated Assessment Update and 2018 Emissions Inventory for Prescribed Fire, Wildfire, and 

Agricultural Burning,” Air Sciences Inc. (December 2002) posted at 

http://www.wrapair.org/forums/fejf/tasks/FEJFtask7.html.) Events were given random 

coordinates in their county based on the USGS Land Cover characteristics map, per the existing 

WRAP emission inventory method. 
WRAP Fire Ph3-4 EI Report_20070515.doc 15

WRAP Baseline Agricultural EI for Nevada

Acres Harvested by Crop and Month

(Annual Average for Baseline Period)

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Month Harvested (and Burned)

Acres Harvested

11 142 2,975 1,133 917 208 1,675 158 200 439 818 884 1,625

10 142 2,975 1,133 917 208 1,675 158 200 439 818 884 1,625

5 195 195 1,346 195 195

4 195 195 1,346 195 195

Churchill HumboldtPershing HumboldtLyon Churchill Lyon Churchill HumboldtLyon Nye HumboldtChurchill Douglas HumboldtLyon Nye

ALFALFA: BARLEY: CORN FOR

SILAGE:

OATS: SPRING

WHEAT:

WINTER WHEAT:

WRAP Baseline Agricultural EI for 

Acres Burned and Number of 

0

20

40

60

80

100

120

140

160

180

200

Ac

re

s

Num Events 2 30 12 10 4 18 2 4 6 10 10 18 2 2 14 2 2

Acres Burned 14.2 297.5 113.3 91.7 20.8 167.5 15.8 20.0 43.9 81.8 88.4 162.5 19.5 19.5 134.6 19.5 19.5

Churchill HumboldtPershing HumboldtLyon Churchill Lyon Churchill HumboldtLyon Nye HumboldtChurchill Douglas HumboldtLyon Nye

ALFALFA: BARLEY: CORN FOR 

SILAGE:

OATS: SPRING 

WHEAT: 

WINTER WHEAT:

Figure 7: Baseline Acres Harvested by Crop, County, and Month for Nevada 

Figure 8: Baseline Agricultural Acres Burned and Number of Burn Events by Crop and County 

for Nevada. 
WRAP Fire Ph3-4 EI Report_20070515.doc 16

The baseline agricultural inventory was identical to Phase II for all states with the exception of 

Nevada. Each event in the baseline agricultural burning fire inventory was categorized as 

"anthropogenic" according the categorization method approved by the ETT and the FEJF. 

2.5 Non-Federal Rangeland Prescribed Burning Baseline Inventory 

The WRAP's Phase II non-federal rangeland prescribed burning inventory for 2002 (the 

development of which was reviewed and approved by the ETT and FEJF) served as the starting 

place for the non-federal rangeland burning baseline inventory. Each event in the baseline 

rangeland burning fire inventory was categorized as "natural" based on the typically low fuel 

loading levels and the reasonable opinion of the FEJF that non-federal rangeland burning is 

typically done to maintain natural fuel conditions. 

The Phase II 2002 non-federal rangeland burning inventory was comprised entirely of allocated 

summary data (i.e., gap-filled data) and was assessed to be representative of the baseline 2000-

2004 period. The top-down approach to estimate rangeland burning activity was documented in 

the Phase II report (Air Sciences, July 2005). Because of the nature of the Phase II non-federal 

rangeland burning level data and the fact that the inventory was "nominal" by design (i.e. no 

actual event-based rangeland burning data is included in the inventory), the Phase II 2002 nonfederal rangeland inventory was used "as is" as the baseline inventory. 

To increase confidence in the rangeland inventory, a brief reality check was performed. Air 

Sciences compared the Phase II 2002 non-federal rangeland acres burned by state to total 

rangeland existing per state appearing in the 1997 National Resources Inventory (NRI) published 

by the USDA – Natural Resources Conservation Service. Rangeland acres burned divided by 

existing rangeland acres created a "percent burned" statistic by state. Figure 9 shows the 

comparison of Phase II rangeland acres burned to NRI rangeland acres existing, as well as the 

percent burned statistic. 
WRAP Fire Ph3-4 EI Report_20070515.doc 17

Figure 9: Comparison of WRAP Phase II Burned NFR Acres to NRI Existing NFR Acres 

The average percent burned of non-federal rangeland acres by state is 0.48%. Oregon was the 

most apparent outlier and had the highest percent burned with 3.23%. The next highest was 

Arizona with 0.77%. Nevada had the lowest percent burned with 0.01% and the next lowest were 

Colorado and Wyoming with 0.05%. If the baseline inventory for non-federal rangeland fire data 

be used for other emission inventory or regional dispersion modeling in the future, users of the 

data should consider further examination of the total acres of non-federal rangeland burned in 

Oregon. 

2.6 Baseline Inventory Results and Comparison to Phase II 

The baseline inventories for wildfire, prescribed burning, and WFU were created by adding or 

subtracting events from the phase II inventory to achieve the baseline targets, as discussed above. 

In that fire days were added or subtracted in their entirety, the baseline target was inevitably 

over exceeded or not reached by a nominal amount. The fire activity and emissions of the final 

baseline inventories are presented in this section. Table 2 tabulates, in summary format, the 

method used to develop the baseline inventories for each fire type. Figure 10 compares Phase II 

to Phase III (Baseline) acreage totals for each fire source, and Figures 11-15 show the comparison 

of Phase II to Phase III (Baseline) inventories for each fire source by state. 

Non-Fed Rangeland:

Phase II (acres burned) vs NRI (acres existing)

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

35,000,000

40,000,000

45,000,000

Acres (Burned or Existing)

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

3.5%

4.0%

4.5%

Percent Burned

NASS (acres) 13,505,375 15,952,019 20,129,123 5,691,125 41,666,273 12,395,570 41,420,424 5,004,806 11,397,443 24,543,574 7,340,047 6,859,879 31,745,109

NRI (acres) 32,323,000 18,269,300 24,574,100 6,500,500 36,750,900 10,689,400 39,989,500 8,372,400 9,286,300 21,876,400 10,733,400 5,856,900 27,302,400

Phase II (acres burned) 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000

Percent Burned (Ph2/NRI) 0.77% 0.22% 0.05% 0.12% 0.41% 0.23% 0.15% 0.01% 3.23% 0.69% 0.23% 0.10% 0.05%

AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 18

Table 2: Summary of Baseline Development and Phase II Comparison Methods 

Fire Source 

Comparison 

Data Set 

Years of 

Comparison 

Averaging 

Method 

Baseline Target 

Equation Adjustments 

Wildfire Fed-5 2000-2003 Mean [Phase II – Fed-5 

2002] 

+ Average (Fed-5) 

AK and UT baseline = 

Fed-5 mean 

Prescribed SIT 2000-2004 Mean [Phase II – SIT 2002] 

+ Average (SIT) 

None 

WFU SIT 2000-2004 Mean [Phase II – SIT 2002] + 

Average (SIT) 

If Phase II < SIT 2002 

then baseline = SIT 

Average; If Phase II or all 

SIT years = 0, then 

baseline = SIT Average; 

ND, SD, WA, OR apply 

de minimis, baseline = 0 

Agricultural Phase II Inventory (as Baseline Inventory) plus a supplemental 

inventory for Nevada. 

 

Rangeland Phase II Inventory (as Baseline Inventory). 

Figure 10: Comparison of WRAP Phase II to Phase III Emission Inventories by Fire Type 

WRAP Phase II vs. Phase III (Baseline) Emissions Inventory 

Annual Acres Burned and Tons PM2.5 Emitted by Fire Type

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

Acres or Tons

Phase II Acres 5,276,485 649,044 201,548 2,162,836 1,042,003

Baseline Acres 4,517,818 669,348 153,697 2,164,166 1,042,003

Phase II PM2.5 1,489,886 71,421 81,505 34,571 15,454

Baseline PM2.5 971,453 72,218 41,171 34,590 15,454

Wildfire Prescribed Burning WFU Agricultural Non-Fed Rangeland
WRAP Fire Ph3-4 EI Report_20070515.doc 19

Comparison of Phase II and Baseline (2000-2004) Inventories

Prescribed Acres Burned and PM2.5 Emissions

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Acres or Tons

Phase II Prescribed Acres 1,108 103,619 86,785 17,425 89,477 77,419 26,826 25,292 5,659 129,290 8,811 14,531 41,196 21,605

Baseline Prescribed Acres 1,244 103,569 69,291 28,746 78,494 77,418 21,030 37,259 8,460 142,153 9,905 18,649 45,109 28,025

Phase II Prescribed PM2.5 177 20,230 9,438 379 11,499 7,067 713 2,029 284 12,568 245 2,021 2,256 2,516

Baseline Prescribed PM2.5 178 20,213 7,564 705 10,222 7,054 555 2,795 397 13,739 332 2,487 2,548 3,428

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY

Figure 11: Comparison of WRAP Phase II to Phase III Wildfire Inventory by State 

Figure 12: Comparison of WRAP Phase II to Phase III Prescribed Burning Inventory by State 

Comparison of Phase II and Baseline (2000-2004) Inventories

Wildfire Acres Burned and PM2.5 Emissions

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

Acres or Tons

Phase II Wildfire Acres 1,790,533 555,873 510,140 412,697 77,678 112,413 83,599 247,243 56,218 921,515 78,384 212,853 89,854 127,486

Baseline Wildfire Acres 1,065,097 220,221 510,092 155,763 566,039 479,068 52,300 197,353 286,362 347,657 124,788 212,828 150,257 149,993

Phase II Wildfire PM2.5 802,701 100,920 112,759 108,436 7,962 10,453 3,665 19,872 5,541 246,411 2,393 30,509 11,854 26,409

Baseline Wildfire PM2.5 452,336 39,491 112,743 34,058 57,046 44,610 2,001 17,886 28,207 98,993 3,560 30,505 22,105 27,912

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 20

Comparison of Phase II and Baseline (2000-2004) Inventories

Agricultural Acres Burned and PM2.5 Emissions

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

Acres or Tons

Phase II Agricultural Acres 0 16,203 727,641 38,231 292,348 8,890 211,932 21,180 0 129,781 5,018 16,684 656,705 38,223

Baseline Agricultural Acres 0 16,203 727,641 38,231 292,348 8,890 211,932 21,180 1,330 129,781 5,018 16,684 656,705 38,223

Phase II Agricultural PM2.5 0 209 8,543 852 4,302 195 2,155 190 0 3,407 136 210 13,797 576

Baseline Agricultural PM2.5 0 209 8,543 852 4,302 195 2,155 190 19 3,407 136 210 13,797 576

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY

Figure 13: Comparison of WRAP Phase II to Phase III WFU Inventory by State 

Figure 14: Comparison of WRAP Phase II to Phase III Agricultural Burning Inventory by State 

Comparison of Phase II and Baseline (2000-2004) Inventories

WFU Acres Burned and PM2.5 Emissions

0

5,000

10,000

15,000

20,000

25,000

30,000

Acres or Tons

Phase II WFU Acres 159,554 0 4,051 22,852 3,543 25 0 4,759 0 0 0 545 0 6,220

Baseline WFU Acres 58,236 1,516 11,914 15,094 10,421 20,017 0 25,262 2,686 0 0 3,302 0 5,250

Phase II WFU PM 2.5 67,616 0 2,304 8,152 1,881 14 0 194 0 0 0 196 0 1,147

Baseline WFU PM2.5 25,710 83 3,510 5,165 2,348 871 0 488 682 0 0 1,221 0 1,092

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 21

Figure 15: Comparison of WRAP Phase II to Phase III Non-Federal Rangeland Burning Inventory 

by State 

2.7 Base Control Case Inventory 

The Phase III Base Control case for fire is the Phase III Baseline inventory with emissions reduced 

to reflect emission reduction techniques (ERTs) being applied to prescribed fire and agricultural 

burning throughout the WRAP region. 

A method to develop a lookup table of seasonal ERTs and associated emission reduction factors 

(ERF) included a Strawman process over the course of several FEJF meetings, Phase III/IV Task 

Team breakout sessions, and conference calls. The primary resource document for this work is 

the Smoke Management Guide for Prescribed and Wildland Fire – 2001 Edition (National 

Wildfire Coordinating Group, Fire Use Working Team). From this document and 

expert/stakeholder input, several EXCEL worksheet tables were developed. In addition, Federal 

Land Mangers (FLM) from each geographic region for which seasonal suites of ERTs have been 

developed provided input to complete the lookup table of seasonal suites of ERTs and the 

associated ERFs. 

The lookup table of ERTs and ERFs generally characterize ERTs by season (winter, spring, 

summer, fall), by vegetation type category (grass, brush, timber, crop), and by geographic region 

(northwest [NW], southwest [SW], and intermountain west [IMW]). Air Sciences and the FLMs 

Comparison of Phase II and Baseline (2000-2004) Inventories

Non-Federal Rangeland Acres Burned and PM2.5 Emissions

0

50,000

100,000

150,000

200,000

250,000

300,000

Acres or Tons

Phase II Rangeland Acres 0 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000

Baseline Rangeland Acres 0 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000

Phase II Rangeland PM 2.5 0 3,708 593 178 119 2,225 371 890 15 4,449 2,225 371 89 222

Baseline Rangeland PM2.5 0 3,708 593 178 119 2,225 371 890 15 4,449 2,225 371 89 222

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc 22

who provided input to prepare the lookup table recognize that that the ERT seasonal suites 

reasonably represent ERTs (and combinations of ERTs) that are typically implemented for the 

regions and vegetation categories. The ERFs are intended to be general estimates of the overall, 

average effectiveness of the seasonal suites of ERTs in reducing emissions of PM2.5. Each ERF 

that has been assigned to a seasonal ERT suite for a geographic region is based upon ERF 

information found in the current literature, estimates of the effectiveness of certain ERTs in 

reducing available fuel loading, and the professional experience of the FLMs who provided input 

to the lookup table. The seasonal suites of ERTs and the ERFs are not intended to be prescriptive 

nor precise in representing the application of ERTs in all cases. 

Seasonal suites of ERTs and the associated ERFs were developed for three regions of the WRAP. 

Each event was classified into a region based on the event's location (state). The regions and 

associated states are: 

• Northwest region (NW): Alaska, Oregon, and Washington 

• Southwest region (SW): Arizona, California, New Mexico, Nevada, and Utah 

• Inter-Mountain West region (IMW): Colorado, Idaho, Montana, North Dakota, South 

Dakota, and Wyoming 

Seasonal suites of ERTs and the associated ERFs were developed for each of the four seasons. 

Each event was classified into a season based on the event's date of burn (month). The seasons 

and associated months are: 

• Winter: December, January, and February 

• Spring: March, April, and May 

• Summer: June, July, and August 

• Fall: September, October, and November 

Seasonal suites of ERTs and the associated ERFs were developed for each of four vegetation 

categories (grass, brush, timber, crop). The fuel category of a prescribed event was determined 

by the National Fire Danger Rating System (NFDRS) fuel model code (fuel model A though U) 

assigned to each event in the Base Case fire inventory. All agricultural burning events were 

assigned the "crop" fuel type. The vegetation categories and associated NFDRS fuel models are: 

• Grass – 

o A - western grasses (annual), 

o L - western grasses (perennial), 

o N - sawgrass, and 

o S - tundra 
WRAP Fire Ph3-4 EI Report_20070515.doc 23

• Brush – 

o B - California chaparral, 

o F - intermediate brush, 

o O - high pocosin, and 

o T - Sagebrush grass 

• Timber – 

o C – pine grass savanna, 

o D - southern rough, 

o E - hardwood litter (winter), 

o G - short needle (heavy dead), 

o H - short needle (normal dead), 

o I - heavy slash, 

o J - intermediate slash, 

o K - light slash, 

o P - southern pine plantation, 

o Q - Alaskan black spruce, 

o R - hardwood litter (summer), and 

o U - western pines 

Accounting for the implementation of ERTs in the Phase III Base Case (2000-2004) fire emissions 

inventory was accomplished by reducing emissions according to the appropriate ERF based on 

the location, timing, and vegetation type of each event. The seasonal suites of ERTs and 

associated ERFs are listed in Table 3. ERFs are defined as the percentage of PM2.5 emissions 

averted due to the application of the seasonal suite of ERTs. 

Table 3: ERFs (percent PM2.5 emissions averted) for Seasonal Suites of ERTs 

 Vegetation Category 

Region Season Grass Brush Timber Crop 

SW Spring 55% 45% 45% 50% 

SW Summer 55% 40% 30% 50% 

SW Fall 55% 45% 45% 70% 

SW Winter 55% 45% 60% 70% 

NW Spring 55% 70% 40% 0% 

NW Summer 65% 45% 45% 30% 

NW Fall 65% 65% 52.5% 70% 

NW Winter 10% 70% 25% 75% 

IMW Spring 55% 40% 40% 50% 

IMW Summer 60% 40% 45% 40% 

IMW Fall 65% 60% 60% 70% 

IMW Winter 25% 50% 20% 0% 
WRAP Fire Ph3-4 EI Report_20070515.doc 24

ERFs were applied to all agricultural burning events, which have all been categorized as 

"anthropogenic" in the Base Case inventory. ERFs were also applied to prescribed broadcast fires 

categorized as "anthropogenic" in the Base Case inventory. Prescribed pile burning events in the 

inventory, also categorized as "anthropogenic," did not have ERFs applied because a unique suite 

of emission factors for pile burning events (which accounts for the emissions control associated 

with pile burning) was already applied to burning events in the Base Case prescribed fire 

inventory. The application of ERFs to prescribed broadcast and agricultural burning events was 

dependent upon specific data contained in each fire record: location (state, cross-walked to ERT 

region), time of burn (month, cross-walked to season), and fuel type (NFDRS, cross-walked to 

fuel category [grass, brush, timber, crop]). 

The Base Control case emissions were calculated by multiplying the PM2.5 emissions from each 

qualifying event in the Base (2000-2004) fire inventory times one minus the by-region, by-season, 

by-fuel category ERF. The application of the ERF is shown in Equation 5. 

 Emissions (Base Control) = Emissions (Base) × (1 – ERF) (5) 

A step-by-step example of the Base Control emissions calculation for a hypothetical prescribed 

burning broadcast event is shown below: 

1. Base PM2.5 emissions from single prescribed broadcast burn event: 

a. Fire type – prescribed fire, broadcast, anthropogenic. 

b. Emissions – 100 tons PM2.5. 

c. Fire location – Southwest (Arizona). 

d. Fire timing – Spring (April). 

e. Vegetation category – Grass (NFDRS fuel model A). 

2. Look up ERF in the ERT Seasonal Suite lookup Table: 55% (Southwest, spring, grass 

fire). 

3. Calculate PM2.5 emissions: 

a. Equation: Emissions (Base Control) = 100 tons PM2.5 × (1 – 0.55) 

b. Result: Emissions (Base Control) = 45 tons PM2.5 

c. Emissions Averted = 55 tons PM2.5 

Figures 16 through 18 display the effectiveness in reducing PM2.5 emissions due to the application 

of ERFs associated with the seasonal suites of ERTs to the qualifying events in the Base Control 

fire inventory. 
WRAP Fire Ph3-4 EI Report_20070515.doc 25

Figure 16: WRAP Phase III Base Control Case: Wildland Prescribed Burning PM2.5 Emissions by 

State With Emissions Averted Due to the Implementation of ERTs 

WRAP Phase III Baseline Control Case 

Prescribed Burning by State: Emissions Averted

0

5,000

10,000

15,000

20,000

25,000

Tons PM2.5

Averted (ERTs on Broad-ANTH) 79 30 1,944 39 3,784 2,395 0 214 16 2,955 0 136 163 840 12,595

Broadcast - ANTH 88 37 2,395 56 3,594 1,857 0 353 19 3,840 0 155 167 587 13,148

Piled - ANTH 4 814 276 273 162 453 0 166 44 4,512 0 195 1,123 296 8,318

Broadcast - NAT 8 19,337 2,955 339 2,688 2,361 556 2,064 319 2,447 333 2,003 1,105 1,708 38,221

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY Grand 

Total
WRAP Fire Ph3-4 EI Report_20070515.doc 26

WRAP Phase III Baseline Control Case 

Prescribed Burning by Fuel Type: Emissions Averted

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

Tons PM2.5

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

Acres

Averted (ERTs on Broad-ANTH) 413 0 12,182 12,595

Broadcast - ANTH 459 0 12,688 13,148

Piled - ANTH 286 34 7,997 8,318

Broadcast - NAT 8,314 2,125 27,782 38,221

Acres 110,105 59,641 499,602 669,348

Brush Grass Timber Grand Total

WRAP Phase III Baseline Control Case 

Agricultural Burning by State: Emissions Averted

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Tons PM2.5

Emissions Averted 110 5,378 298 2,350 101 1,509 118 13 1,207 68 121 4,238 264 15,774

Baseline Control PM2.5 99 3,164 554 1,952 94 647 72 6 2,200 68 89 9,559 312 18,816

AZ CA CO ID MT ND NM NV OR SD UT WA WY Grand 

Total

Figure 17: WRAP Phase III Base Control Case: Wildland Prescribed Burning PM2.5 Emissions 

and Acres by Vegetation Category With Emissions Averted Due to the Implementation of ERTs 

Figure 18: WRAP Phase III Base Case Control: Agricultural Burning PM2.5 Emissions by State 

With Emissions Averted Due to the Implementation of ERTs 
WRAP Fire Ph3-4 EI Report_20070515.doc 27

SECTION 3 

PROJECTION (2018) FIRE EMISSION INVENTORIES 

Projection (2018) inventories were built from the baseline inventories for wildfire, wildland fire 

use, prescribed burning, agricultural burning, and non-federal rangeland burning (described in 

Section 2). 

Prescribed burning, wildfire, and WFU burning projection emission inventories were each 

created by "scaling" the respective baseline inventory up or down based on input presented 

during the two technical Workshops that was provided by the Interagency Fuels Committee 

(IFC) to the FEJF. The non-federal prescribed rangeland burning projection inventory was built 

by "scaling" the NFR baseline inventory up or down based on input from the USDA - National 

Resource Conservation Service (NRCS) and FEJF. For each fire type, sets of scalars were 

developed to create less, likely, and more projection inventories. A likely agricultural burning 

projection inventory was created by removing events from the baseline inventory to reflect 

known limits to future agricultural burning. The less, likely, and more scalars for each fire type 

are shown in Table 4. 

Table 4: Summary of 2018 Projection Scalars for the Less, Likely, and More Scenarios 

Fire Type Breakdown Less Likely More 

Prescribed By state 

and agency 

Fed. Agencies = IFC x 

0.25 

State/Private/Other 

= baseline 

Fed. Agencies = IFC x 

0.5 

State/Private/Other 

= baseline x 2 

Fed. Agencies = IFC 

 

State/Private/Other 

= baseline x 3 

Wildfire By state 0.9 x (WF base + 

WFU base) 

0.5 x (WF base + 

WFU base) 

0.5 x (WF base + 

WFU base) 

WFU By state 0.1 x (WF base + 

WFU base) 

0.5 x (WF base + 

WFU base) 

(WF base + WFU 

base) 

Agricultural By state Baseline - limits to 

future burning 

Rangeland By state 0.5 x NRCS 2018 

Estimate 

NRCS 2018 Estimate 2.0 x NRCS 2018 

Estimate 

In addition, the results from the 2018 projection inventories for each fire type were grouped into 

three air quality planning suites to reflect possible future burning scenarios (see Section 3.5). 

These suites include, 

• Base Case, reflecting the most probable scenario. 

• Climate Conditions/Resource Limited, reflecting high rates of wildfire and WFU and 

resource constraints for prescribed burning. 

• Maximum Application of Prescribed Fire, influenced by the IFC’s targets for prescribed 

burning. 
WRAP Fire Ph3-4 EI Report_20070515.doc 28

3.1 Prescribed Burning Projection Inventory 

The WRAP's Phase III Baseline (2000-2004) prescribed fire inventory (described in Section 2.2) 

served as the starting place for the prescribed fire projection inventory. The projection inventory 

for prescribed burning was built by scaling the baseline inventory based on IFC target acres and 

FEJF scalars. 

The IFC provided projected activity targets (in acres) for broadcast and piled burning by state 

and agency. The participants of the Technical Workshops used the IFC targets to develop the 

agency- and scenario-specific scalars. The IFC targets were used to establish the "more" 

prescribed burning scenario scalars for federal agencies. For state, private, and other agencies, 

the “more” scenario scalar was set to three times baseline. The "likely" scenario scalars were 

calculated using half of the IFC target acres for federal agencies and twice the baseline values for 

state, private, and other agencies. The "less" scenario scalars were calculated using one-quarter of 

the IFC target acres for federal agencies and equal to baseline the baseline values for state, 

private, and other agencies. For all WRAP states other than Nevada, the scalars for the less 

scenario were set to ensure that the “less” scenario projections were at least equal to the baseline 

values for the federal agencies. For Nevada, 2018 prescribed burning levels for the less scenario 

were established at 1,553 acres below baseline levels. 

The 2018 scaled projection inventories were assembled by adding events to the baseline 

prescribed burning inventory based on the by-state, agency, and burn type scalars in the same 

manner as described for creating the baseline prescribed inventory from Phase II events in 

Section 2.2, with the exception that a random date was assigned to new, repeated events. For the 

projection inventories, new repeated events were given a date within seven days before or after 

the original date. ERTs were applied to the 2018 projection inventory using a similar technical 

methodology as used for the Base Control case described in Section 2.7. Figure 19 shows the 

projected prescribed acres compared to baseline prescribed acres. Figure 20 shows the affect on 

PM2.5 emissions of applying ERTs to the prescribed projection inventory. 
WRAP Fire Ph3-4 EI Report_20070515.doc 29

WRAP Phase IV 2018 Fire Projection EI 

Prescribed Burning: Burn Type (with Alaska)

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

Tons PM2.5

0

2

4

Millions

Acres

Averted (ERTs on Broad-ANTH) 12,595 24,978 50,385 96,894

Broadcast - ANTH 13,148 29,413 59,396 114,889

Piled - ANTH 8,318 11,256 22,816 40,080

Broadcast - NAT 38,221 60,192 120,281 238,422

Acres 669,348 966,251 1,959,146 3,704,081

Baseline Less Likely More

WRAP Phase IV 2018 Fire Projection EI 

Prescribed Burning Scenarios

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

Acres

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

Tons PM2.5

Baseline Acres 1,244 103,569 69,291 28,746 78,494 77,418 21,030 37,259 8,460 142,153 9,905 18,649 45,109 28,025

Less Acres 5,505 150,072 95,680 41,621 116,860 122,538 26,772 78,718 6,906 188,369 13,726 29,403 60,077 30,006

Likely Acres 11,002 297,937 191,740 90,329 234,519 250,593 54,509 160,830 15,491 379,089 31,157 59,196 121,514 61,242

More Acres 22,029 601,074 375,276 182,153 459,294 453,779 94,572 305,973 30,341 672,849 61,633 118,668 210,439 116,003

Baseline PM2.5 180 20,218 7,570 707 10,227 7,067 556 2,796 398 13,753 333 2,490 2,558 3,430

Less PM2.5 165 33,489 8,565 1,102 15,158 8,175 707 6,977 335 15,058 375 4,057 3,949 2,749

Likely PM2.5 250 66,278 17,618 2,318 30,889 16,609 1,446 13,807 735 30,212 805 7,805 7,989 5,730

More PM2.5 502 133,829 34,079 4,652 60,790 30,587 2,529 27,189 1,443 54,490 1,657 15,785 14,807 11,052

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY

Figure 19: WRAP Phase IV 2018 Projection Inventory: Prescribed Burning PM2.5 Emissions and 

Acres by State for Each Scenario 

 

Figure 20: WRAP Phase IV 2018 Projection Inventory: Prescribed Burning PM2.5 Emissions and 

Acres by Scenario With Emissions Averted Due to the Implementation of ERTs 
WRAP Fire Ph3-4 EI Report_20070515.doc 30

3.1.1 Prototype or “Stem Cell” Events 

The 2018 prescribed burning inventories were created from the Phase III (baseline) inventory by 

adjusting the baseline inventory based on the scalars (specific to state, agency, and burn type) 

developed during the two Technical Workshops. This scaling method resulted in fire activity in 

areas of some states, agencies, and burn types, which did not exist in the baseline inventory. In 

order to include this fire activity in the 2018 inventories, prototype or "stem cell" events were 

created and added to the baseline seed events. 

Stem cell fire events were created to create events for each state-agency-burn type combination 

with acres projected by the IFC activity targets but without acres in the baseline inventory. The 

stem cell events were then used to augment the baseline events utilized by the Projection 

Calculation Tool (described in Section 1.1) to create the prescribed burning projection inventories. 

In order to include fire events in the projection inventory that are spatially and temporally 

reasonable, a 12 kilometer grid was created for the WRAP region. For each grid cell (based on the 

location of the centroid of the grid cell), fuel loading, agency jurisdiction, and natural or 

anthropogenic emissions, along with state, county, and time zone was determined. The fuel 

loading was calculated from the NFDRS code and the natural or anthropogenic categorization 

was determined based on the fuel characteristic classification system (FCCS) code at each 

centroid. By creating the stem cell events from the grid centroids, each event has site-specific fuel 

information as well as accurate location information. 

The average burn size for prescribed broadcast burns in the baseline inventory is 50 acres and for 

piled burns it is 25 acres. In the baseline inventory, the spring month with the most broadcast 

acres burned is April and the fall month with the most activity is October. For piled burning, the 

spring month with the most burned acres is also April and the fall month with the most piled 

burning is November. For each grid cell with state and agency combinations needing stem cell 

events, 50 acre broadcast burns and 25 acre piled burns were created with the appropriate sitespecific fuel information. To add events to the projection inventory in the appropriate stateagency combinations, an appropriate broadcast burn stem cell event was assigned a random burn 

date in April and October and added to the projection inventory until the target value of acres 

was reached. Similarly, stem cell piled events were added to the projection inventory with a 

random burn date in April and November until the targets are reached. The emissions from each 

stem cell event were calculated based on site-specific fuel loading and acres burned. 

Stem cell events were created for 40 state-agency combinations and comprised approximately 

20,000 acres out of 1,000,000 acres in the 2018 prescribed burning “less” projection inventory, 

about 45,000 acres of the 2,000,000 acres in the “likely” projection inventory, and approximately 

90,000 acres out of the 3,700,000 acres in “more” projection inventory. In each inventory, the stem 

cell events account for approximately 2 percent of the total acres. 
WRAP Fire Ph3-4 EI Report_20070515.doc 31

3.2 Wildfire and Wildland Fire Use Projection Inventory 

The WRAP's Phase III Baseline (2000-2004) wildfire and Wildland Fire Use (WFU) inventories 

(described in Section 2.1 and Section 2.3, respectively) served as the starting place for the wildfire 

and WFU projection inventories. The projection inventories for wildfire and WFU were built by 

summing total baseline wildfire and WFU acres from the baseline inventory and allocating the 

total acres on a by state basis using the activity targets provided by the IFC and the FEJF 

projection scalars. The IFC provided projected activity targets (in acres) for WFU by state and 

agency. In general, the IFC activity targets indicate that Federal Land Managers intend to utilize 

the WFU designation for more naturally caused wildland fire events in the future. Therefore, the 

participants in the Technical Workshops elected to represent significantly more wildland fire 

acres as WFU in the projection inventory. 

The wildfire and WFU scalars are presented in Table 4. For all scenarios, WFU acres were 

allocated on a by-state basis by allocating the total wildfire and WFU acres according to IFC 

activity targets. The IFC activity targets were used to allocate WFU by state by calculating each 

state's target acres as a percent of the total target acres. 1

The 2018 scaled wildfire and WFU projection inventories were assembled by combining the 

wildfire and WFU baseline inventories and randomly selecting events from the combined set for 

each fire type regardless of the original baseline fire type of each event. This technique ensured 

that each inventory had spatially and temporally realistic fire events and increased the number of 

seed events that were available to be pulled from the seed data and added to the projection 

inventory for the WFU “more” scenario. The scaled 2018 wildfire and WFU inventories were 

created from events in the baseline inventories in the same manner as the creation of the baseline 

wildfire inventory from the Phase II wildfire inventory (described in Section 2.1). An exception 

to this method is that the date given to new, repeated events was plus or minus seven days from 

the original date. In addition, WFU events were limited to fire events smaller than 50,000 acres 

(except in Alaska). For wildfire, one abnormally large fire in Arizona was removed from the seed 

data. Figure 21 shows wildfire and WFU acres and PM2.5 for each scenario compared to baseline 

wildfire and WFU acres and PM2.5. Figure 22 shows wildfire and WFU projected acres by state 

compared to baseline acres. 

 

1 State-by-state WFU activity targets to not reflect the role that Smoke Management Programs may play in permitting 

wildland fires to be managed as Wildland Fire Use events. 
WRAP Fire Ph3-4 EI Report_20070515.doc 32

WRAP Phase IV 2018 Fire Projection EI 

Wildfire and WFU by State 

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

Baseline

Likely

More

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY

Acres

Sum of WFU

Sum of Wildfire

WRAP Phase IV 2018 Fire Projection EI 

Wildfire and WFU (with Alaska)

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

Acres

0

1

2

Millions

Tons PM2.5

Total Acres 4,671,515 4,606,074 6,934,577

Wildfire Acres 4,517,818 2,291,618 2,291,618

WFU Acres 153,697 2,314,456 4,642,959

WF+WFU PM2.5 1,012,663 1,088,938 1,642,907

Baseline Likely More

Figure 21: Comparison of WRAP Phase III to Phase IV Wildfire and Wildland Fire Use Acres and 

PM2.5

Figure 22: Comparison of WRAP Phase III to Phase IV Wildfire and Wildland Fire Use Acres and 

PM2.5 by State 

 
WRAP Fire Ph3-4 EI Report_20070515.doc 33

3.3 Agricultural Burning Projection Inventory 

As determined during the two Technical Workshops for developing the projection inventories, 

only a "likely" scenario that accounts for variations from the Phase III (baseline) for agricultural 

burning was developed. To determine the extent, if any, the projection inventory should vary 

from baseline activity levels for agricultural burning, legal documents (such as state and local 

bills and statutes) were examined for codified limits to present and future agricultural burning. 

The agricultural projection inventory was created by removing activity from the baseline 

inventory to reflect the known limits to future agricultural burning. The projected emission 

inventory was created to reflect realistic burning patterns (on a spatial and temporal scale) with a 

reasonable projected activity level. In addition, ERTs were applied to the 2018 projection 

agricultural inventory in the same manner as for the base-control case discussed in Section 2.7. 

For agricultural burning, the foreseeable variations from baseline resulted from changes in 

allowable burning levels throughout the WRAP region. The "likely" inventory was therefore 

developed by starting with the baseline (2000-2004) agricultural burning inventory and removing 

agricultural burning activity based on future or current (2005) limitations on burning. The 

allowable burning levels were gleaned through a search of literature, rules, regulations, and 

statute of state and local agencies in the WRAP region. Each limit was examined for its effect on 

the baseline inventory and fire events were dropped accordingly. Specifically, events in the 

baseline emission inventory were dropped (by geographic area and crop type) as necessary to 

meet the burning level targets (in acres), identified in the literature search. 

The quality controlled baseline emission inventory was created from reported and estimated 

burning levels centering on 2002, and is therefore deemed accurate for fire size, fuel type, 

location, and time of burns. By starting with the baseline agricultural burning inventory and 

then dropping events for regulation changes, the 2018 projection inventory remained realistic on 

a spatial and temporal basis. That is, fire events in the projected inventory were of realistic size, 

location and timing. 

A summary of the bills, statute, rules, and regulations that were examined is presented in the 

numbered list that follows. The consequent acres removed from the baseline inventory to arrive 

at the projected inventory are also identified. 

1. Pima County: Only tumbleweed can be burned in Pima County, Arizona. 

Area: Pima County, Arizona

Citation: Pima County Code 17.12.480 - .500 

Implementation Method: Select all burning except ditches and ditch banks in Pima 

County.
WRAP Fire Ph3-4 EI Report_20070515.doc 34

Affected Acres in Baseline: 0 acres 

Proposed Acres Removed: 0 acres 

2. Sacramento Valley: Rice Straw burning limited to 125,000 acres per year in the 

Sacramento Valley Air Basin. 

Area: Sacramento Valley air basin includes the California counties: Shasta, Placer, Butte, 

Colusa, Yolo, Sacramento, Tehama, Glenn, Yuba, Sutter, and Solano

Citation: Connelly-Areias-Chandler Rice Straw Burning Reduction Act 

Implementation Method: Select all rice straw burning in the Sacramento Valley Air 

Basin counties. 

Affected Acres in Baseline: 155,078 acres 

Proposed Acres Removed: 30,154 acres (randomly chosen events, total acres removed is 

slightly more than necessary due to randomly removing entire events) 

3. San Joaquin Valley: Eliminate burning of all agricultural wastes in the San Joaquin 

Valley starting June 2006. 

Area: San Joaquin Valley air basin includes the California counties: San Joaquin, 

Stanislaus, Merced, Madera, Fresno, Kings, Tulane, and Kern (western part)

Citation: Senate Bill 1056 

Implementation Method: Select all burning in the San Joaquin Valley Air Basin 

counties. 

Affected Acres in Baseline: 402,987 acres 

Proposed Acres Removed: 402,987 acres2

4. Southwest Air District: Best Management Practices allows very little agricultural 

burning in Washington's Southwest Clean Air Agency district. 

Area: Southwest Clean Air Agency includes the Washington counties: Clark, Cowlitz, 

Lewis, Skamania, and Wahkiakum

Citation: BMP Part II (WAC 173-430) 

Implementation Method: Select all burning in Washington's Southwest Clean Air 

Agency counties. 

Affected Acres in Baseline: 0 acres 

Proposed Acres Removed: 0 acres 

 

2 The efforts to quantify the effects on agricultural emissions of regulations that will be implemented in the future did not 

consider the degree to which exemptions to the regulations would be utilized. 
WRAP Fire Ph3-4 EI Report_20070515.doc 35

5. Willamette Valley: Open field burning limited to 65,000 acres (40,000 acres regular 

burning, 22,000 acres identified species, 3,000 acres steep terrain) and propane flaming 

limited to 37,500 acres in the Willamette Valley. 

Area: The Willamette Valley includes the Oregon counties of: Columbia, Washington, 

Multnomah, Yamhill, Clackamas, Polk, Marion, Linn, Benton, Lane, and Douglas

Citation: Field Burning Rule 603-077-0101 

Implementation Method: Select all burning in the Willamette Valley counties.

Affected Acres in Baseline: 51,845 acres 

Proposed Acres Removed: 0 acres 

The agricultural burning inventory does not include information regarding the type of 

burn (i.e. regular, identified species, steep terrain, propane flaming) and therefore the 

specific limits by type of burn cannot be assessed. However, from 2002 to 2005 the total 

average open-field burning in the Willamette Valley was 50,000 acres with an addition 

average of 1,700 acres of propane flaming. The baseline inventory includes 51,845 acres 

(including propane flaming) and is therefore deemed average, resulting in no removal of 

acres from the baseline inventory. 

6. Washington Orchards: No orchard removal in Washington in 2018. 

Area: Washington State

Citation: Discussions at Phase III/IV Technical Workshop 2.5 in Seattle 

Implementation Method: Select all orchard removal burning in Washington.

Affected Acres in Baseline: 1334 acres 

Proposed Acres Removed: 1334 acres 

The total fire activity that was dropped for the 2018 projection inventory was 434,475 acres 

accounting for 4,999 tons PM2.5 (Figure 23). Of the agricultural activity that was dropped, 99.7% 

of acres occurred in California. Within California, a majority (97%) of the activity removed was 

from the San Joaquin Valley. The only other state with fire activity removed from baseline for the 

2018 projection inventory was Washington for orchard removal. 
WRAP Fire Ph3-4 EI Report_20070515.doc 36

WRAP Phase IV 2018 Agricultural Burning Projection EI

Baseline vs 2018 Projection Inventory (Proposed)

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

Acres

Baseline Acres 0 16,203 727,641 38,231 292,348 8,890 211,932 21,180 1,330 129,781 5,018 16,684 656,705 38,223 2,164,166

2018 Acres 0 16,203 294,500 38,231 292,348 8,890 211,932 21,180 1,330 129,781 5,018 16,684 655,371 38,223 1,729,691

Acres Removed 0 0 433,141 0 0 0 0 0 0 0 0 0 1,334 0 434,475

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY Grand Total

Figure 23: Agricultural Burning Baseline Versus 2018 Projection Inventory 

The total agricultural burning activity in the baseline fire inventory was 2,164,166 acres. The total 

agricultural burning activity in the projected (2018) fire inventory is 1,729,691 acres, or 80% of 

baseline activity. The total PM2.5 emissions and acres in the projected inventory and the 

emissions averted from the application of ERTs are shown in Figure 24. 
WRAP Fire Ph3-4 EI Report_20070515.doc 37

WRAP Phase IV 2018 Fire Projection EI 

Agricultural Burning by State: Emissions Averted

0

1,000

2,000

3,000

4,000

5,000

6,000

Tons PM2.5

0

100000

200000

300000

400000

500000

600000

Acres

Emissions Averted 128 2,320 193 1,700 99 1,294 127 13 843 34 107 4,652 203

PM2.5 81 1,322 659 2,602 96 862 63 6 2,563 102 103 9,040 373

Acres 16,203 294,500 38,231 292,348 8,890 211,932 21,180 1,330 129,781 5,018 16,684 655,371 38,223

AZ CA CO ID MT ND NM NV OR SD UT WA WY

Figure 24: Agricultural Burning Projection EI Acres Burned, Tons PM2.5 Emitted, and Emission 

Averted from the Application of ERTs 

3.4 Non-Federal Rangeland Prescribed Burning Projection Inventory 

The WRAP's Phase III Baseline (2000-2004) non-federal rangeland (NF) fire inventory (described 

in Section 2.5) served as the starting place for the NFR projection inventory. The projection 

inventory for NFR was built by scaling up the baseline inventory based on NRCS projected acres 

and FEJF scalars. The NRCS provided projected acres by state, which were determined by the 

participants of the Technical Workshops as the likely scenario. The Workshop participants 

determined that the less scenario should be half of the NRCS projected acres by-state and the 

more scenario should be twice the NRCS projected acres by-state.3 

The baseline non-federal rangeland events were used to assemble the scaled projection inventory 

in the same manner as the creation of the baseline wildfire inventory from the Phase II wildfire 

inventory. Figure 25 shows the projected NFR acres compared to the baseline NFR acres. 

 

3 In the Air Quality Planning Suites (described in Section 3.5) only the likely scenario was utilized. 
WRAP Fire Ph3-4 EI Report_20070515.doc 38

Figure 25: Comparison of WRAP Phase III to Phase IV 2018 Non-Federal Rangeland Burning 

Likely Inventory by State 

3.5 Air Quality Planning Suites 

The technical approach to produce projection inventories for each of the fire types included the 

development of “less,” “likely,” and “more” scenarios. The projection inventories are intended 

for use by the WRAP and its Regional Modeling Center (RMC) to estimate future air quality 

impacts associated with fire emissions. As a practical matter, the resources of the WRAP to have 

the RMC execute regional dispersion models are limited. Therefore, the FEJF was asked to 

identify a limited number of combinations of fire emissions (one scenario from each of the five 

fire types) to serve as the Air Quality Planning Suites for fire. The Air Quality Planning Suites 

are summarized in Table 5. 

WRAP Phase IV 2018 Fire Projection EI 

Non-Federal Prescribed Rangeland Burning by State

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

Acres

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Tons PM2.5

Baseline Acres 0 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000 1,042,003

Likely Acres 0 374,721 40,000 19,969 9,962 149,901 34,951 119,937 1,000 300,001 150,001 34,734 5,929 15,000 1,256,106

Baseline PM2.5 0 3,708 593 178 119 2,225 371 890 15 4,449 2,225 371 89 222 15,454

Likely PM2.5 0 5,558 593 296 148 2,223 518 1,779 15 4,449 2,225 515 88 222 18,630

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY Grand 

Total
WRAP Fire Ph3-4 EI Report_20070515.doc 39

Table 5: Summary of Air Quality Planning Suites 

Fire Type 

Baseline 

Control Case 

Base 

Case 

Climate 

Conditions/ 

Resource 

Limited 

Maximum 

Application of 

Prescribed Fire 

Wildfire Baseline Likely More Likely 

WFU Baseline Likely More Likely 

Prescribed Baseline with ERT Likely Less More 

Rangeland Baseline Likely Likely Likely 

Agricultural Baseline with ERT Likely Likely Likely 

Base Case Planning Suite. This suite reflects the most "likely" fire emissions scenario for 2018. 

This suites avoids extremes of either mostly prescribed or mostly wildfire burning. As shown in 

Table 5, the base case suite is comprised of all of the likely inventories. The base case suite can be 

compared to baseline to estimate changes in emissions and visibility due to fire from the baseline 

period (2000-2004) to 2018. This suite would reflect favorable conditions for prescribed burning 

in most states and steady funding for fuels treatment using prescribed fire. 

Climate Conditions and Resource Limited Suite. This suite reflects the highest expected levels 

of wildfire and wildland fire use in 2018. This suite includes low prescribed fire usage (due to 

unfavorable fuel and weather conditions). This suite is comprised of the “more” inventory for 

wildfire and WFU, the “less” inventory for prescribed burning, and the “likely” inventory for 

agricultural and NFR burning. The climate conditions and resource limited suite can be 

compared to baseline to estimate the potential change in emissions and visibility impacts due to 

prolonged drought, heaving loadings of dry fuels, and constrained resources. 

Maximum Application of Prescribed Fire Suite. This suite reflects prescribed burning at the 

Interagency Fuels Committee's target activity levels. The suite includes the “more” inventory for 

prescribed burning and the “likely” inventories for wildfire, WFU, agricultural burning, and NFR 

burning. The maximum application of prescribed fire suite can be compared to baseline to 

estimate the possible change in emissions and visibility impacts due to the maximum application 

of prescribed fire. This suite would reflect the maximum funding for treatment and ideal 

conditions for burning. It could also be used to estimate the maximum potential air quality 

benefit that could be accomplished through the application of ERTs to prescribed fire events. 

3.6 Projection Inventory Results and Comparison to Baseline 

The 2018 projection inventories for prescribed burning, wildfire, WFU, and NFR were created by 

adding or subtracting events from the baseline inventory to achieve the projection targets, as 

discussed above. These inventories were then compiled into air quality planning suites to reflect 
WRAP Fire Ph3-4 EI Report_20070515.doc 40

future burning scenarios and allow for comparison to baseline to analyze possible changes in 

emissions and visibility impacts due to fire. The fire activity and emissions of the final 2018 

projection inventories are presented in this section. Figure 26 presents the acreage and PM2.5

totals for the Phase III Baseline, Baseline Control, Phase IV Base Case suite, Climate Conditions 

and Resource Limited suite, and the Maximum Application of Prescribed Fire suite for each fire 

source. 

Figure 26: Summary of Phase IV Projection Inventory Air Quality Planning Suites 

WRAP Phase IV 2018 Fire Projection EI 

Source Activity Scenarios Grouped into Air Quality Planning Suites

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

5,000,000

Acres

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

Tons PM2.5

Prescribed Acres 669,348 1,959,146 966,251 3,704,081

WFU Acres 153,697 2,314,456 4,642,959 2,314,456

Wildfire Acres 4,517,818 2,291,618 2,291,618 2,291,618

Agricultural Acres 2,164,166 1,729,691 1,729,691 1,729,691

NF Rangeland Acres 1,042,003 1,256,106 1,256,106 1,256,106

Prescribed PM2.5 59,687 202,493 100,861 393,391

WFU PM2.5 41,173 574,159 1,128,127 574,159

Wildfire PM2.5 971,490 514,780 514,780 514,780

Agricultural PM2.5 18,816 17,871 17,871 17,871

NF Rangeland PM2.5 15,454 18,630 18,630 18,630

Baseline Control Case Base-case Climate conditions/

resource limited Max-App of Rx Fire

("Likely" activity and emission scenario choosen unless otherwise noted) More More More Less

 
APPENDIX A 

Technical Methodologies Used to Create Event-Based Fire 

Records in the 2002 Phase II Fire Emission Inventories 
WRAP Fire Ph3-4 EI Report_20070515.doc A-ii

CONTENTS Page

A.1 Fuel Loading and Emission Factors ........................................................................................................................A-1

A.2 Emission Calculations..............................................................................................................................................A-3

A.3 Day-After Smoldering Emissions Added to Eligible Fires ........................................................................................A-3

A.4 Plume Profile ...........................................................................................................................................................A-4

A.4.1 Virtual Acres .................................................................................................................................................A-4

A.4.2 Diurnal Consumption ....................................................................................................................................A-4

A.4.3 Fire Size Classes and Plume Profile Calculations........................................................................................A-5

A.5 Natural and Anthropogenic Assignments (For All Fire Sources) ...........................................................................A-14

Tables 

Table A-1: Summary of Fuel Loading and Consumption by NFDRS Model .................................................................A-2

Table A-2: Summary of Emission Factors.....................................................................................................................A-3

Table A-3: Standard Diurnal Consumption Template Used to Distribute Fire-Total Heat Production and Emissions ..A-5

Table A-4: Fire-Related Parameters as Function of Fire Size Classes.........................................................................A-5

Table A-5: Buoyant Efficiency as Function of Hour of Day ...........................................................................................A-6

Table A-6: SCCs and Their Fire Type and Natural/Anthropogenic Classification.......................................................A-15

Table A-7: Prescribed Fire NFDRS Fuel Model Categorization as Natural or Anthropogenic....................................A-17

Figures 

Figure A-1: Buoyant Efficiency......................................................................................................................................A-7

Figure A-2: Projected Top of Plume..............................................................................................................................A-7

Figure A-3: Projected Bottom of Plume.........................................................................................................................A-8

Figure A-4: Proportion of Plume in Surface Layer ........................................................................................................A-9

Figure A-5: Fire Size Class 1 Plume Characteristics ..................................................................................................A-10

Figure A-6: Fire Size Class 2 Plume Characteristics ..................................................................................................A-11

Figure A-7: Fire Size Class 3 Plume Characteristics ..................................................................................................A-12

Figure A-8: Fire Size Class 4 Plume Characteristics ..................................................................................................A-13

Figure A-9: Fire Size Class 5 Plume Characteristics ..................................................................................................A-14
WRAP Fire Ph3-4 EI Report_20070515.doc A-1

A.1 Fuel Loading and Emission Factors 

In the event that fire event-specific fuel loading values were not contained in the database record, 

fuel loading in tons per acre for the wildfire inventory were assigned using the NFDRS fuel 

model codes and a table of fuel loading values for NFDRS fuel model categories (Cohen and 

Deeming, 1985). In addition to the default NFDRS fuel loadings, additional fuel loading was 

added to each category to adjust for fuel present as duff and tree crowns. Similarly, for 

prescribed fire events for which no fuel loading value was available, the prescribed fire fuel 

loading values were the same as those used for the wildfire inventory. “Adjusted” NFDRS fuel 

loading assignments for wildfire and prescribed burning differed by the percent consumption 

assumed for live fuels, duff, and crown components. Table A-1 presents the adjusted NFDRS 

fuel loading assignments for wildfire and prescribed burning. 

An emission factor suite was developed to apply to wildfire and prescribed fire activity data. 

The emission factor suite included one look-up table for wildfire and prescribed broadcast burns 

and one table for prescribed pile burns. The twelve pollutants included were total suspended 

particulate matter (TSP), particulate matter less than 10 microns in diameter (PM10), particulate 

matter less than 2.5 microns in diameter (PM2.5), elemental carbon (EC), organic carbon (OC), 

non-methane volatile organic compounds (VOC), methane (CH4), ammonia (NH3), oxides of 

nitrogen (NOx), carbon monoxide (CO), sulfur dioxide (SO2), and coarse particulate matter– 

defined as the difference between PM10 and PM2.5 (PMC). The emission factor suite consists of 

two look-up tables. Two emission factor references were drawn upon: the U.S. Environmental 

Protection Agency’s (U.S. EPA) AP-42 Section 13.1 and an emission inventory methods survey 

report (Battye, 2001) funded by the U.S. EPA Office of Air Quality Planning and Standards 

(OAQPS). The emission factor suite is a compilation of emission factors and emission factor 

relationships (multipliers) from both documents. Table A-2 lists the emission factors used for the 

Phase II EI. 

In addition to smoldering consumption incorporated into the NFDRS fuel loading table, distinct 

smoldering emissions were added to the emission inventory on the day after certain wildland fire 

days (see Section A.3). 
WRAP Fire Ph3-4 EI Report_20070515.doc A-2

Table A-1: Summary of Fuel Loading and Consumption by NFDRS Model for Wildfire, WFU, and Prescribed Fire. Dead and live fuel loadings were based on Cohen and Deeming (1985). Values in parentheses indicate total fuel loading foasterisk (*) after the NFDRS model description indicates the wildfire emissions were augmented for smoldering consumpti

Dead Fuels (tons/acre) Live Fuels (tons/acre) 

NFDRS Abbr. NFDRS Model Description 

Total, 

WF/WFU 

(Rx fire) 

(tons/acre) 1-hour 

10- 

hour 

100- 

hour 

1,000- 

hour 

Fine 

Wood Herbaceous 

A Western grasses (annual) 0.50 0.20 0.00 0.00 0.00 0.00 0.30 B California chaparral 19.5 3.50 4.00 0.50 0.00 11.50 0.00 C Pine-grass savanna 4.7 0.40 1.00 0.00 0.00 0.50 0.80 D Southern rough * 15.6 (10.6) 2.00 1.00 0.00 0.00 3.00 0.75 E Hardwood litter (winter) * 3.8 1.50 0.50 0.25 0.00 0.50 0.50 F Intermediate brush 15.0 2.50 2.00 1.50 0.00 9.00 0.00 G Short needle (heavy dead) * 43.5 (25.6) 2.50 2.00 5.00 12.00 0.50 0.50 H Short needle (normal dead) * 27.5 (15.0) 1.50 1.00 2.00 2.00 0.50 0.50 I Heavy slash * 55.1 (49.1) 12.00 12.00 10.00 12.00 0.00 0.00 J Intermediate slash * 34.0 (31.2) 7.00 7.00 6.00 5.50 0.00 0.00 K Light slash * 14.4 (13.1) 2.50 2.50 2.00 2.50 0.00 0.00 L Western grasses (perennial) 0.75 0.25 0.00 0.00 0.00 0.00 0.50 N Saw grass * 5.0 1.50 1.50 0.00 0.00 2.00 0.00 O High pocosin * 46.1 (45.1) 2.00 3.00 3.00 2.00 7.00 0.00 P Southern pine plantation * 16.4 (10.2) 1.00 1.00 0.50 0.00 0.50 0.50 Q Alaskan Black Spruce 57.6 (48.8) 2.00 2.50 2.00 1.00 4.00 0.50 R Hardwood litter (summer) * 3.1 0.50 0.50 0.50 0.00 0.50 0.50 S Tundra * 19.3 (19.1) 0.50 0.50 0.50 0.50 0.50 0.50 T Sagebrush grass * 4.5 1.00 0.50 0.00 0.00 2.50 0.50 U Western pines * 19.1 (10.3) 1.50 1.50 1.00 0.00 0.50 0.50 
WRAP Fire Ph3-4 EI Report_20070515.doc A-3

Table A-2: Summary of Emission Factors 

Summary of emission factors (EF) in pounds per ton for prescribed burning. In the case of piled 

fuels, when two sources are mentioned, the first source refers to the emission factor and the 

second to the empirical relationship used to derive that emission factor. 

Prescribed Fire 

Piled Fuels 

Prescribed Fire 

Non-Piled 

Pollutant EF Source EF Source 

TSP 12.0 AP424 34.1 AP42 

PM10 8.0 AP42 28.1 OAQPS 

PM2.5 8.0 AP42 24.1 OAQPS 

Elemental Carbon 0.6 AP42, OAQPS PM2.5 * 0.072 1.5 OAQPS 

Organic Carbon 4.3 AP42, OAQPS PM2.5 * 0.54 11.6 OAQPS 

VOC 6.3 AP42, OAQPS CO * 0.085 13.6 OAQPS 

CH4 7.7 OAQPS 2*(42.7-43.2*CE) 13.6 OAQPS 

NH3 0.5 AP42, OAQPS CO * 0.0073 1.3 OAQPS 

NOx 6.2 OAQPS 6.2 OAQPS 

CO 74.3 AP42 289.0 OAQPS 

SO2 1.7 OAQPS 1.7 OAQPS 

PM coarse 0.0 PM10 – PM2.5 4.0 PM10 – PM2.5

A.2 Emission Calculations 

For wildfire and prescribed burning, daily emissions were calculated as fuel consumed (tons of 

fuel) multiplied by each emission factor (pounds of pollutant per ton of fuel). Total fuel 

consumed was either extracted directly from the activity data (more often the case with 

prescribed fire) or was calculated as the size of the fire (acres burned) multiplied by the 

“adjusted” NFDRS fuel loading value (tons of fuel per acre burned). For wildfires and prescribed 

broadcast burns of fuel model types with a fuel loading greater than 5 tons per acre, additional 

smoldering emissions were assigned to the same location on the following calendar day. 

A.3 Day-After Smoldering Emissions Added to Eligible Fires 

Emissions due to smoldering were estimated and added to the emissions estimates for wildland 

broadcast fire events. Fire events associated with heavy fuel loading (based on the National Fire 

Danger Rating System fuel model assigned to each event) were assumed to produce smoldering 

emissions on the day after each day of burning (assumed to be flaming-phase days). For 

smoldering-eligible wildfire and WFU events, smoldering emissions were assumed to be 17 

percent of the emissions of the previous day (personal communication with David Sandberg, 

USDA – Forest Service (retired)). For smoldering-eligible prescribed fire events, smoldering 

 

4 AP-42, Section 13.1, Table 13.1-3, Logging Slash Debris, No Mineral Soil, weighted average of flaming and smoldering. 
WRAP Fire Ph3-4 EI Report_20070515.doc A-4

emissions were assumed to be 8.5 percent of the emissions of the previous day. Smoldering 

emissions were not added to pile burning events. 

A.4 Plume Profile 

A plume profile tailored for wildland fire was assigned to each daily fire event. Normally, plume 

rise is predicted using hourly pyrotechnical and meteorological information. However, given the 

unique physical characteristics of wildland fire events and previous experience with dispersion 

models that indicated questionable performance with regard to dispersing smoke plumes, the 

FEJF utilized expert opinion to assign plume characteristics to each fire event. 

It is important to note that there are alternative methods available to represent smoke plumes in 

regional dispersion models. In 2007, the FEJF intends to coordinate a stakeholder group to 

investigate the available methods and any associated research on model performance. The focus 

of the stakeholder group will be to determine if the FEJF should recommend that the WRAP’s 

plume assignment method be modified or replaced in order to enhance the performance of the 

WRAP’s regional modeling analyses with regard to smoke impacts. Users of the WRAP’s 

modeling results and entities that conduct regional dispersion modeling using the WRAP’s fire 

emission input files should factor these technical realities into the interpretation and use of 

regional modeling results. 

A.4.1 Virtual Acres 

Fires were classified into size classes based on “virtual acreage.” The virtual acreage was 

calculated by multiplying the actual fire size by the square root of the normalized pre-burn fuel 

loading (Equation A-1). This was done in order to relate fuel loading to the characteristic “stack” 

diameter of the plume. Total fuel loading was normalized to 13.8 tons per acre for wildfire and 

5.0 tons per acre for prescribed fire. The normalizer for wildfire was equal to the total surface 

loading plus a portion of the crown biomass of NFDRS fuel model U (western pines). The 

prescribed fire normalizer is equal to the surface loading only of NFDRS fuel model U. 

Acreage Acreage Fuel Loading / Normalizer virtual actual = ⋅ Equation A-1 

The plume profile for days added to model smoldering for the day after an original activity day 

was the same as for the original fire event. In the emission inventory, the smoldering events 

retained the virtual acreage of the fire event they were created from, and thus the plume 

calculations were identical. 

A.4.2 Diurnal Consumption 

A diurnal fuel consumption table was created to allocate daily wildland fire emissions by hour 

(Table A-3). The table, consisting of a percent of fuel consumed for each hour of the day, 
WRAP Fire Ph3-4 EI Report_20070515.doc A-5

summing to 100, was submitted to the Air Quality Modeling Forum (and the WRAP’s Regional 

Modeling Center [RMC]). The diurnal fuel consumption table was implemented by the RMC 

within the SMOKE emissions processor to allocate daily emission estimates to hourly emissions. 

Table A-3: Standard Diurnal Consumption Template Used to Distribute Fire-Total Heat Production 

and Emissions 

Hour 1 2 3 4 5 6 7 8 9 10 11 12 

% Per 

Hour 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 0.57 2.00 4.00 7.00 

 

Hour 13 14 15 16 17 18 19 20 21 22 23 24 

% Per 

Hour 10.00 13.00 16.00 17.00 12.00 7.00 4.00 0.57 0.57 0.57 0.57 0.57 

A.4.3 Fire Size Classes and Plume Profile Calculations 

Plume values include the top and bottom of the plume (Ptop and Pbot, respectively; both 

expressed in meters above ground elevation) and the percent of emissions entrained within the 

surface layer of the atmosphere (Lay1F), defined by the ETT of the FEJF as the first 38 meters 

above the ground.5 These three plume parameters are established and assigned for each of the 24 

hours of each daily fire event. All of the plume values were assigned based on the limited 

information available for each fire event, including fire size (fire area grown per day) and either a 

reported fuel loading or the NFDRS fuel model. 

Five plume classes were defined with increasing potential plume heights to reflect the range of 

“heat release” possible in wildland fires (Table A-4). Plume bottom heights and percent of the 

plume fumigated to the first layer of the atmosphere were also developed for the five plume 

classes. Using expert opinion and anecdotal evidence, a table of hourly buoyant efficiency values 

was derived (Table A-5). 

Table A-4: Fire-Related Parameters as Function of Fire Size Classes 

Class 1 2 3 4 5 

Size 

(virtual acres) 0 – 10 >= 10 – 100 >= 100 – 1,000 >= 1,000 – 5,000 >= 5,000 

BEsize 0.40 0.60 0.75 0.85 0.90 

Ptop max (m) 160 2,400 6,400 7,200 8,000 

Pbot max (m) 0 900 2,200 3,000 3,000 

 

5 The height of the first (lowest) vertical layer is 38 m in the WRAP’s Regional Modeling Center’s model setup. The 

calculation methodology for the Lay1F values have been reviewed (by Air Sciences and the USDA Pacific Wildland Fire 

Sciences Lab) and assessed to be reasonable with no additional scaling. The maximum bottom of plume values was 

revised downward for the three largest fire size classes (also based on discussions with the USDA Pacific Wildland Fire 

Sciences Lab). 
WRAP Fire Ph3-4 EI Report_20070515.doc A-6

Table A-5: Buoyant Efficiency as Function of Hour of Day 

Hour 1 2 3 4 5 6 7 8 9 10 11 12 

BEhour 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.06 0.10 0.2 0.4 

 

Hour 13 14 15 16 17 18 19 20 21 22 23 24 

BEhour 0.7 0.8 0.9 0.95 0.99 0.8 0.7 0.4 0.06 0.03 0.03 0.03 

Equations were used to calculate Ptop and Pbot as a function of time of day and size of the fire 

(expressed in terms of virtual acres). Note that the calculations used an hourly value for buoyant 

efficiency (Table A-5) and heat release value based on fire size, also referred to as normalized fire 

growth. 

The hourly top of the plume was calculated as follows: 

( )( ) max

2

size

2 Ptophour = BEhour

* BE * Ptop (A-2) 

Where: BE is the buoyant efficiency looked up from the hourly or size class tables. The 

hourly bottom of plume was similarly calculated as: 

( )( ) max

2

size

2 Pbot hour = BEhour

* BE *Pbot (A-3) 

Lastly, an equation was used to calculate Lay1F, the proportion of emissions fumigated into the 

first atmospheric layer. Lay1F was calculated as the arithmetic inverse of the hour-specific 

buoyant efficiency multiplied by the size-specific buoyant efficiency. 

( ) hour hour BEsize Lay1F = 1 - BE * (A-4) 

Using Equations A-1 through A-4, the bottom and top of the atmospheric plume as well as the 

proportion of the plume fumigated into the first atmospheric surface layer were all scaled to fire 

size, fuel loading (incorporated in virtual acres calculation), and hour of the day. Figures A-1 

through A-4 illustrate the relationships described above. 

Figures A-1 through A-9 illustrate the hourly plume characteristics (Ptop, Pbot, and Lay1F) 

assigned to each of the five fire size classes into which daily fire events in the Phase II EI have 

been assigned (Class 1 - less than 10 acres; Class 2 – 10 to 100 acres; Class 3 – 100 to 1,000 acres; 

Class 4 – 1,000 to 5,000 acres; Class 5 – greater than 5,000 acres). Also shown on Figures A-5 

through A-9 is the height (38 m) of the first vertical atmospheric layer (as designated by the 

WRAP’s RMC). 
WRAP Fire Ph3-4 EI Report_20070515.doc A-7

Projected Top of Plume

1.0

10.0

100.0

1000.0

10000.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m) [log-scale]

>5000

1000-5000

100-1000

10-100

<10

Figure A-1: Buoyant Efficiency 

The relationship between buoyant efficiency and time of day. 

Figure A-2: Projected Top of Plume 

The projected top of the atmospheric plume (meters) as a function of time of day and fire size. 

Fire sizes represent the upper cutoff of the fire size categories. The lowest line represents the 10-

acre cutoff. Note the logarithmic scale on the Y-axis. 

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10 12 14 16 18 20 22

Hour

Buoyant efficiency
WRAP Fire Ph3-4 EI Report_20070515.doc A-8

Projected Bottom of Plume

1.0

10.0

100.0

1000.0

10000.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m) [log-scale]

>5000

1000-5000

100-1000

10-100

<10

Figure A-3: Projected Bottom of Plume 

The projected bottom of the atmospheric plume (meters) as a function of time of day and fire size. 

Fire sizes represent the upper cutoff of the fire size categories. The line representing the 10-acre 

cutoff is constant at a value of zero. 
WRAP Fire Ph3-4 EI Report_20070515.doc A-9

Figure A-4: Proportion of Plume in Surface Layer 

The proportion of the plume fumigation to the atmospheric surface layer (<38 m) as a function of 

time of day and fire size. Fire sizes represent the upper cutoff of the fire size categories. The 

highest line represents the 10-acre cutoff. 

Percent Entrained Lowest Vertical Layer

0%

25%

50%

75%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m) [log-scale]

>5000

1000-5000

100-1000

10-100

<10
WRAP Fire Ph3-4 EI Report_20070515.doc A-10

Figure A-5: Fire Size Class 1 Plume Characteristics 

This figure shows plume characteristics (Ptop, Bbot, and Lay1F) for Class 1 fires for each hour. 

Plume height in meters is shown on the left Y-axis (in log-scale), and Lay1F in percent entrained 

into the lowest vertical layer is shown on the right Y-axis. For reference, the height of the lowest 

vertical layer (38 m) is shown in red. 

WRAP Plume Rise Class 1: Virtual Acres <10

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m)

0%

25%

50%

75%

100%

% entrained in lowest vertical layer

P_top

P_bot

Reference

Lay1F
WRAP Fire Ph3-4 EI Report_20070515.doc A-11

WRAP Plume Rise Class 2: Virtual Acres 10-100

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m)

0%

25%

50%

75%

100%

% entrained in lowest vertical layer

P_top

P_bot

Reference

Lay1F

Figure A-6: Fire Size Class 2 Plume Characteristics 

This figure shows plume characteristics (Ptop, Bbot, and Lay1F) for Class 2 fires for each hour. 

Plume height in meters is shown on the left Y-axis (in log-scale), and Lay1F in percent entrained 

into the lowest vertical layer is shown on the right Y-axis. For reference, the height of the lowest 

vertical layer (38 m) is shown in red. 
WRAP Fire Ph3-4 EI Report_20070515.doc A-12

Figure A-7: Fire Size Class 3 Plume Characteristics 

This figure shows plume characteristics (Ptop, Bbot, and Lay1F) for Class 3 fires for each hour. 

Plume height in meters is shown on the left Y-axis (in log-scale), and Lay1F in percent entrained 

into the lowest vertical layer is shown on the right Y-axis. For reference, the height of the lowest 

vertical layer (38 m) is shown in red. 

WRAP Plume Rise Class 3: Virtual Acres 100-1000

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m)

0%

25%

50%

75%

100%

% entrained in lowest vertical layer

P_top

P_bot

Reference

Lay1F
WRAP Fire Ph3-4 EI Report_20070515.doc A-13

Figure A-8: Fire Size Class 4 Plume Characteristics 

This figure shows plume characteristics (Ptop, Bbot, and Lay1F) for Class 4 fires for each hour. 

Plume height in meters is shown on the left Y-axis (in log-scale), and Lay1F in percent entrained 

into the lowest vertical layer is shown on the right Y-axis. For reference, the height of the lowest 

vertical layer (38 m) is shown in red. 

WRAP Plume Rise Class 4: Virtual Acres 1000-5000

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m)

0%

25%

50%

75%

100%

% entrained in lowest vertical layer

P_top

P_bot

Reference

Lay1F
WRAP Fire Ph3-4 EI Report_20070515.doc A-14

WRAP Plume Rise Class 5: Virtual Acres >5000

1

10

100

1000

10000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour

Plume height (m)

0%

25%

50%

75%

100%

% entrained in lowest vertical layer

P_top

P_bot

Reference

Lay1F

Figure A-9: Fire Size Class 5 Plume Characteristics 

This figure shows plume characteristics (Ptop, Bbot, and Lay1F) for Class 5 fires for each hour. 

Plume height in meters is shown on the left Y-axis (in log-scale), and Lay1F in percent entrained 

into the lowest vertical layer is shown on the right Y-axis. For reference, the height of the lowest 

vertical layer (38 m) is shown in red. 

A.5 Natural and Anthropogenic Assignments (For All Fire Sources) 

Each wildfire, wildland fire use event, prescribed burn, agricultural burn, and non-federal 

rangeland burn in the baseline and projection emission inventories for fire was flagged as 

“natural” (NAT) or “anthropogenic” (ANTH). There are two principal reason for categorizing 

fire events as natural or anthropogenic: 

1. To allow the results of the WRAP’s regional dispersion modeling to be used to 

distinguish “natural background” conditions from man-made impacts. 

2. To identify anthropogenic fire events in the emission inventories for which the 

emission reduction effects of applying Emission Reduction Techniques can be 

estimated. 

It is important to note that the results of implementing the NAT/ANTH categorization method in 

the Phase II (historical 2002), Phase III (baseline) and Phase IV (projection) inventories do not 

necessarily reflect actual emissions that are, in fact, natural or anthropogenic. While the 

NAT/ANTH categorization criteria are based on sound logic and available information 
WRAP Fire Ph3-4 EI Report_20070515.doc A-15

pertaining to fuel levels and conditions, the application of these criteria to historical or nominal 

events only produces a representative breakdown of fire emissions into natural and 

anthropogenic categories. State and Tribal Smoke Management Programs that actively track 

fires, make burn-no-burn decision, require the application of Emission Reduction Techniques to 

burns, and who categorize burns as NAT/ANTH at the time of the burn will be able to generate 

actual inventories of natural and anthropogenic emissions from fire. 

NAT/ANTH categorization was done using the following approaches, based on the WRAP Fire 

Emissions Joint Forum’s 2001 WRAP Policy for Categorizing Fire Emissions and Guidance for 

Classifying Natural Versus Anthropogenic Fire Emissions.

6 (Posted at the “Fire Categorization” 

heading at http://www.wrapair.org/forums/fejf/docs.html). The FEJF database for fire was 

amended with a field to flag each fire event as natural or anthropogenic. Also, the Source 

Classification Code (SCC) assignment performed in the database was refined to assign custom 

SCCs, which accommodate specific fire types discussed in this document. Each SCC present in 

the emission inventory identifies each event as either natural or anthropogenic. The SCC stays 

with the fire event in the SMOKE model-ready files delivered to the WRAP Regional Modeling 

Center (RMC). These SCCs are defined in Table A-6.7

Table A-6: SCCs and Their Fire Type and Natural/Anthropogenic Classification 

SCC Fire Type Natural or Anthropogenic 

2810001000 Wildfire Natural 

2810001001 WFU Natural 

2810001002 WFU Anthropogenic 

2801500000 Agricultural Anthropogenic 

2801500001 Agricultural (Native 

American) 

Natural 

2810015000 Prescribed Anthropogenic 

2810015001 Prescribed Natural 

2810016000 Non-Federal Rangeland Anthropogenic 

2810016001 Non-Federal Rangeland Natural 

The categorization criteria are summarized in the following bullets: 

• Wildfire. All wildfire was categorized as natural (SCC 2810001000). was considered 

exclusively natural. 

 

6Alternative approaches for categorizing natural and anthropogenic fires are discussed in Appendix B. 

7 After reviewing the WRAP’s Phase II emission inventories, the US Environmental Protection Agency provided the 

WRAP with a proposed list of SCC’s for all type and categories of fires. The WRAP has not implemented EPA’s proposed 

SSC list and continues to assign SCCs to fire events per the Phase II method described herein. EPA’s proposed list is 

included for reference as Appendix D to this report. 
WRAP Fire Ph3-4 EI Report_20070515.doc A-16

• Wildland Fire Use. All Wildland Fire Use (WFU) incidents were categorized as natural 

(custom SCC of 2810001001). It is helpful to note that by definition WFU is a distinct fire 

source from both wildfire and prescribed burning. That is, a WFU incident cannot also be 

considered wildfire or prescribed burning. In the event that entities within the WRAP 

modify the categorization of WFU incidents to include anthropogenic events, a custom 

SCC of 2810001002 has been reserved as a placeholder. 

• Agricultural Burning. All agricultural burning in the Phase II EI was categorized as 

anthropogenic (standard SCC 2801500000). The 2001 WRAP Policy for Categorizing Fire 

Emissions states that “vegetative burning conducted by Native Americans for traditional, 

religious, and ceremonial purposes” is considered natural. All other vegetative burning 

conducted by Native Americans is classified as “prescribed,” with agricultural burning 

fitting the definition of prescribed fire. Some agricultural fire events in the inventories 

occur within the exterior boundaries of tribal lands, but the data from which the baseline 

and projection events are made lack an indication of “traditional, religious, or 

ceremonial” purpose. Therefore agricultural events falling on tribal lands were 

categorized as anthropogenic. A custom SCC of 2801500001 has been reserved as a 

placeholder should agricultural burning determined to be of a natural origin in future 

inventories. 

• Prescribed Fire. Prescribed fire events were categorized as either natural or 

anthropogenic. The standard SCC of 2810015000 was used for anthropogenic prescribed 

burns, and a custom SCC of 2810015001 was used for natural burns. Because the raw 

activity data for prescribed fire do not include a natural or anthropogenic identifier, nor 

do the raw data contain burning objective information (e.g., “maintenance” or 

“restoration”), the Emissions Task Team (ETT) of the FEJF elected to base the 

categorization of prescribed fire as natural or anthropogenic on the National Fire Danger 

Rating System (NFDRS) fuel model for each incident (Table A-7). For example, heavy 

fuel loads or "restoration" burns were identified as anthropogenic, while lighter fuel 

loads or "maintenance" burns were identified as natural. 

An NFDRS fuel model exists for each prescribed burn in the inventories. Each incident 

has only one NFDRS assignment based on: 1) the observed fuel model reported in the 

activity database (preferred); or 2) based on NFDRS assignment by overlaying the fire 

location on the national NFDRS fuel model map using GIS (see the WRAP 1996 Fire 

Emission Inventory documentation). The NFDRS categorizations as natural or 

anthropogenic were based on examining the text descriptions of the NFDRS fuel models. 

If fuel model descriptions indicated a buildup of “above normal” fuel loadings (for 

example, the short-needle conifer model G), then the NFDRS fuel model was categorized 

as anthropogenic. If the fuel model descriptions indicated normal fuel loading levels (for 

example, short-need conifer model (H), then the NFDRS fuel model was categorized as 
WRAP Fire Ph3-4 EI Report_20070515.doc A-17

natural. Regardless of NFDRS fuel model, all piled prescribed burns were categorized as 

anthropogenic. 

Table A-7: Prescribed Fire NFDRS Fuel Model Categorization as Natural or Anthropogenic 

NFDRS 

Fuel Model Categorization Short Vegetation Description 

A Natural Western annual grasslands 

B Anthropogenic Tall dense older brush 

C Natural Open pine with grass understory 

D Natural Southeast fuel types 

E Natural Hardwood after leaf fall 

F Natural Mature closed Chamise with Oakbrush 

G Anthropogenic Dense Conifer with heavy downed duff 

H Natural Short-needled Conifer with thin litter 

I Anthropogenic Clearcut Conifer Slash <6" 

J Anthropogenic Clearcut heavily thinned Conifer Slash <6" 

K Anthropogenic Light conifer slash partial cuts 

L Natural Western perennial grasslands 

N Natural Southeast fuel types 

O Natural Southeast fuel types 

P Natural Southeast fuel types 

Q Natural Upland Alaska Black Spruce 

R Natural Hardwoods after leafout 

S Natural Alpine Tundra and grass 

T Natural Sagebrush and grasslands 

U Anthropogenic Closed Western Long-Needled Pine 

Piles Anthropogenic Piled activity fuels

• Non-Federal Prescribed Rangeland Burning. The ETT elected to assign all non-federal 

rangeland burning events in the inventory as natural (custom SCC 2810016001). This 

decision was deemed to be consistent with the intent of the WRAP’s categorization 

policy. The decision is also based on the facts that fuel loading assignments for nonfederal rangeland burning events are assigned generally (i.e., there are no event-specific 

fuel loading data for nonfederal rangeland fire events in the inventory) and fuel loading 

is low (1.75 tons of fuel per acre). The SCC 281001600 will be reserved for anthropogenic 

non-federal rangeland burning in case the categorization technique changes for the 

future fire inventories. 

The ETT also acknowledged the following: 
WRAP Fire Ph3-4 EI Report_20070515.doc A-18

• Non-federal rangeland burning should be regarded similarly to wildland prescribed 

burning in that efforts to control emissions should be implemented when and where 

possible. 

• The FEJF’s fire tracking system (to be developed) should accommodate data that 

indicates the stated objective(s) of non-federal rangeland burning events. The 

categorization technique for non-federal rangeland burning may be modified for future 

inventories. 
APPENDIX B 

Uncertainty Analysis and Exceptions for WRAP Phase IV 

Fire Event Projection Methodology 
WRAP Fire Ph3-4 EI Report_20070515.doc B-ii

CONTENTS Page

B.1 "Rounding Error" from Scalars and Activity Targets................................................................................................B-1

B.2 "Rounding Error" Statistics ......................................................................................................................................B-1

B.3 Assignment of Natural vs. Anthropogenic Fire Events ............................................................................................B-1

B.4 Assignment of Smoldering Values for Fire Event Records......................................................................................B-3

Tables 

Table B-1: Total Acres Burned From Prescribed Burns From the Phase II (2002) Emission Inventory When 

Applying the NFDRS NAT/ANTH Classification Scheme and the FCCS/FRCC Scheme..........................B-3

Table B-2: Impact of Missing Emissions From Smoldering Events on Baseline total PM2.5 ........................................B-3
WRAP Fire Ph3-4 EI Report_20070515.doc B-1

B.1 "Rounding Error" from Scalars and Activity Targets 

Multiplying a baseline fire event level times its scalar produces an activity target in acres. By 

design, the 2018 Fire Event Projection Calc-Tool populates fire-days (with their complete acres 

and emissions) up to this activity target. For every jurisdiction for which the Projection 

Calculation Tool builds an inventory, the event-based projection emission inventory will deviate 

from the activity targets. This deviation can be thought of as a "rounding error” in the 2018 fire 

event projection. 

B.2 "Rounding Error" Statistics 

The "Rounding Error" deviation was assessed by-state or by-agency or by-burn type for all fire 

types and scenarios, although the assessment did not aim to examine each prescribed 

state/agency/burn type combination. The average deviation for all 124 scalars needed for the 

2018 projection suites is 2.6%. There were 10 projections that had a deviation of over 10%. The 

projection target of these events was less than 100,000 acres; therefore, these events could be 

affected by a large fire in the seed data.

B.3 Assignment of Natural vs. Anthropogenic Fire Events 

The National Fire Danger Rating System (NFDRS) is the method currently used by the USDA 

Forest Service, and many other organizations to integrate the effects of topography, fuels, risk 

conditions and current or predicted weather into numerical indices of fire danger on a day-to-day 

basis. The fire danger rating of an area gives the manager a tool to assist in the day-to-day "fire 

business" decisions. The NFDRS is a tool that is considered along with the manager’s local 

knowledge of the area and consequences of the decision when arriving at the best solution to a 

fire business decision or problem. 

Phase II fire events were categorized as Natural or Anthropogenic based on the NFDRS fuel 

model described above. In this method, heavy fuel loads (restoration mode, where fuel 

conditions deviate significantly from natural conditions) were classified as "Anthropogenic" fires, 

while lighter fuel loads (maintenance mode, where fuel conditions approximate natural 

conditions) were classified as "Natural" events. The NFDRS method has been used in previous 

fire emission inventories and is described in the Fire Emissions Joint Forum Meeting (September 

27-29, 2005) in Missoula, MT (http://www.wrapair.org/forums/ef/meetings/050927/Ph_3-

4_MissoulaMT_20050928.pdf). 

As an alternative to the NFDRS method, the FEJF with the assistance of Air Sciences Inc. devised 

the National System of Fuel Characteristic Classification/Fire Regime Condition Class 

(FCCS/FRCC) method of classifying fire events as Natural or Anthropogenic. Participants at the 

first Phase III/IV Workshop proposed using the FCCS/FRCC method to categorize events as 

Natural or Anthropogenic for the WRAP fire models. 
WRAP Fire Ph3-4 EI Report_20070515.doc B-2

The FCCS is a comprehensive software system used to build, characterize, and classify fuel beds 

to accurately capture the structural complexity and geographical diversity of fuel components 

across landscapes and provide the ability to assess elements of human (e.g. logging slash) and 

natural (e.g. insect and disease) change. The FCCS could be characterized as a more resolved 

version of the NFDRS and a system that is more centered on characterizing vegetation conditions, 

in general, than on characterizing fuel conditions as they pertain to fire danger. It analyses fuel 

conditions and assigns each a descriptor name and a fuel loading mass. 

The FRCC is an interagency, standardized tool for determining the degree of departure from 

reference (historical) conditions for vegetation, fuels and disturbance regimes. The FRCC 

examines FCCS fuel types and assigns each fuel class a certain fire danger level. The three fire 

regime condition classes are based on no or low (FRCC 1), moderate (FRCC 2), and high (FRCC 3) 

departure from the central tendency of the reference conditions. Low departure (FRCC 1) 

describes fire regimes and vegetation-fuel conditions considered to be within the natural range of 

variability. 

The FEJF devised a NAT/ANTH categorization method that utilizes FCCS and FRCC. All FCCS 

that correspond to FRCC1 are categorized as Natural fire events. FRCC2 events represent 

moderate departures from reference conditions. The FRCC2 class represents conditions, which 

may require fire, hand or mechanical treatment to restore conditions to the natural fire regime. 

The FCCS that correspond to FRCC2 are not considered entirely natural or anthropogenic and 

fall between maintenance and restoration modes. The Natural or Anthropogenic assignment for 

this class is based on a review of FCCS fuel model information (fuel loading, duff depth, 

description, etc.). FRCC3 represents areas having high departures from reference conditions, 

which may need high levels of restoration to return to natural conditions. All FCCS that 

correspond to FRCC3 are characterized as Anthropogenic. Further information about FCCS and 

FRCC is available online at: http://www.fs.fed.us/pnw/fera/fccs/ and 

http://www.frcc.gov/ respectively. 

Although the FEJF and Air Sciences had developed the FCCS/FRCC method to categorize fire 

events with the intention of implementing the method in the baseline inventory, Air Sciences 

implemented the NFDRS-based NAT/ANTH classification scheme (in a continuation of the 

method implemented in the Phase II inventory). The Phase III baseline inventories using the 

NFDRS scheme have already been used in model runs for the RMC. In order to facilitate the 

comparison of Phase IV to Phase III model results, Air Sciences decided, with the concurrence of 

the FEJF, to continue using the NFDRS method for categorizing fire events in the Phase IV 

inventories as Natural or Anthropogenic. (This exception applies only to prescribed broadcast 

burns. The NAT/ANTH categorization of other categories of fire events (wildfire, WFU, NFR, 

agricultural burning, and prescribed pile burns) are based on criteria other than fuel loading.) 
WRAP Fire Ph3-4 EI Report_20070515.doc B-3

In the interest of full documentation of this step in the processing of the Phase IV emission 

inventory files, Air Sciences has prepared a statistical comparison of the Natural versus 

Anthropogenic categorization methods using the Phase II (2002) fire emission inventory for 

prescribed fires. Air Sciences applied the FCCS/FRCC parameters to the Phase II (2002) fire 

emission inventory and compared those results to the Phase II EI using the NFDRS classification 

scheme to statistically review how the classification of total fire acres would change. The results 

are shown in Table B-1. 

Table B-1: Total Acres Burned From Prescribed Burns From the Phase II (2002) Emission Inventory 

When Applying the NFDRS NAT/ANTH Classification Scheme and the FCCS/FRCC Scheme 

 Total Acres 

Description Natural Anthropogenic 

Phase II RX w/ NFDRS 348,000 301,000 

Phase II RX w/ FCCS/FRCC 326,000 323,000 

Net Change -6.7% +6.8% 

The table above shows that when using Phase II emission inventory data as a case study, the 

FCCS method would categorize more total burned acres as Anthropogenic (restoration mode) as 

compared to the NFDRS method. 

B.4 Assignment of Smoldering Values for Fire Event Records 

In the baseline and baseline control case inventories, emissions for some wildfire and WFU 

events were underestimated because some fire events that were eligible to have smoldering 

records added were not correctly processed in the emissions inventory system. The missing 

emissions from smoldering events impacted only the baseline and baseline control case. The 

emissions processing error was corrected for the Phase IV 2018 fire projection inventories. As 

shown in Table A2 below, emissions from wildfire and WFU events in the Phase III baseline and 

baseline control inventories were underestimated by 19,148 tons of PM2.5 (approximately 4 

percent of the entire inventory). When comparing model runs for the baseline and projection 

cases, the additional emissions of PM2.5 not present in the baseline cases should be considered. 

Table B-2: Impact of Missing Emissions From Smoldering Events on Baseline total PM2.5 

Description Wildfire WFU

PM2.5 Tons 19,147 1.579

Percent of fire-specific PM2.5 4% 2%
APPENDIX C 

Reviewer Comments and Corrective Actions 
WRAP Fire Ph3-4 EI Report_20070515.doc C-1

Table C-1: Reviewer comments with responses and corrective action taken

Page Response 

2 Where can we get the “EXCEL-based spreadsheet tool to generate nominal fire events database” tool described on page 2

 Addressed on page 3: "It is anticipated that the CalculatiTool will be available to states and Tribes in the spring of 2007 as a technical tool on the WRAP’s web-based TechnSupport System."

5

Spatial distribution of future fires is based on a single latitude/longitude coordinate of the original or seed fire event. It might be a better approach to distribute large fire 

emissions across multiple grids. Such as the Mc Nalley fire that would have burned across a minimum of 17 (36 km x 36 km) grid cells. 

Addressed in text on pp. 5-6. The location (latitude and longitude) of the event was not changed (from the 2002 Ebecause when the emissions input data are processed by WRAP’s Regional Modeling Center, each emissions evenassociated with the 36 km by 36 km grid cell (i.e., the lati

and longitude of the event is not preserved in the results the model runs). The Emissions Task Team of the FEJF determined to not change the latitude and longitude of thevent going into the baseline inventory so that the emissifrom the event would appear in the same RMC grid cell.Locations of fire events in the were based on RMC inputs. (continued in the cell below)(continued from the cell above) A 36x36 km grid cell is equivalent to 320,000 acres and therefore resolving a fire beyond a single lat/lon would not improve accuracy in tvast majority of modeling cases. In the instance addresseby the commenter, the McNally fire perimeter was 150,00acres, with general dimensions of 48 km north-south x 28 east-west. In the baseline EI, if the McNally fire from the 2002 EI was pulled randomly to populate the baseline EIlocation would be represented as a lat/lon coordinate anthe RMC would represent the entire event as occurring in single 36x36km grid cell. This is an acknowledged limita

of the EI and the regional modeling. A more resolved method could potentially distribute a fire like the McNalfire into 2 (at the very most 4) grid cells

5 What are the calculated “scalars” for CA for WF, WFU and Rx burning, and the supporting values (i.e.: baseline targets and Fed 5 2000-2004 averages)? Provided in the Figures and supporting tables in Sections 

(Wildfire), 2.2 (Prescribed Burning) , and 2.3 (Wildland FUse). 
WRAP Fire Ph3-4 EI Report_20070515.doc C-2

Table C-1: Reviewer comments with responses and corrective action taken

10

Since SIT data is not generally considered the source for prescribed fire data within the fire community, I'm wondering if you should elaborate on why it was chosen. Isn't it the case that the SIT data was the best available source (most complete record)

for the time period? If you were to conduct the same analysis today, for more recent years, I don't think the SIT data would be the source folks would expect you to go to.

The SIT data was the best available source (most complerecord) for the time period.

28 What are the IFC (interagency fuels committee) target acres for Rx burning, in relation to the Rx baseline? Specifically addressed on page 28, paragraph 2, and sho

visually in Figure 19, page 29. 

34

. The assumption that there will be zero ag burning the San Joaquin Valley in the future in not likely. Exemptions in the San Joaquin Valley rules will allow for future burning of ag material. 

The efforts to quantify the effects on agricultural emissio

regulations that will be implemented in the future did nconsider the degree to which exemptions to the regulatiowould be utilized. States, Tribes, and many Federal LanManagers participated in the two technical workshops aseveral FEJF meetings at which the method to quantify teffect of regulations of future emissions from fire were presented and discussed. 

Figure 21

 The assumption that WFUs will be 15 times higher as the “likely” scenario in 2018 is

not reasonable for CA because of our nonattainment areas. Fire permits are required for WFUs in CA and due to poor air quality in adjacent Air Districts; it is not realistic that WFU will be allowed to burn at a rate 15 times higher then the base case in CA. Although the total sum of WF and WFUs are the same in the baseline and likely scenarios, shifting the majority of fire activity from WF category to WFUs category in 2018 is not likely for CA.

Figure 21 shows projection results on a WRAP-wide basand is not intended to reflect state-by-state results. Individual state projections for WFU are depicted in Fig22. The increase in wildland fire is due to the predominposition that clilmate change and worsening fuels condiwill result in a higher incidence of wildfires. The shift to more utilization of WFU to accomplish land managemenobjectives (as opposed to suppression of wildfire) is a predominant position among Federal Land Managers. T"rules of thumb" for each scenario used to split wildland into wildfire and WFU were applied uniformly across alstates (i.e., the scalars were not developed on a state-by-basis). State-by-state WFU activity targets to not reflect role that Smoke Management Programs may play in permitting wildland fires to be managed as Wildland FiUse events. States, Tribes, and many Federal Land Man

participated in the two technical workshops and several meetings at which the scalars to develop projections for wildfire and WFU were developed, presented, and discu
WRAP Fire Ph3-4 EI Report_20070515.doc C-3

Table C-1: Reviewer comments with responses and corrective action taken

Table 4

This table is confusing. Rx burns are divided into Less, Likely and More categories. However, in the text, WF and WFUs are divided into different scenarios named Baseline, Likely and More. Is the Rx Less scenario go with the WF/WFU Baseline scenario? And how does the description on P 27 line up – “base case,” “climate conditions/resource limits,” and “maximum application of prescribed fire” with the categories in the table? Also, the fire scenario breakdowns and descriptions in the table are difficult to follow. Recommendation: reformat table, provide clear descriptions of the scenarios beneath the table and provide consistent categorization nomenclature across the fire types in the text.

Table 4 and the quoted description on pg 27 refer to two different things. Section 3.5 of the report describes in dethe air quality planning suites.

Table A1

Are the fuel loading or fuel consumption assumptions the same for WFU, WF and Rx

burns the same? This table lists Rx fires only, though the text says the table applies to WF, Rx and WFUs? If fuel loading (consumption) assumptions are the same for WF and Rx, how do you account for WF characteristics that often burn hotter and consume canopy fuels vs. Rx burn that do not?

Table A-1 addresses WF,WFU and Rx fires. Rx fuel consumption values are shown in parentheses when thedeviate from WF and WFU values; fuel consumption vafor WF and WFU are assumed equivalent.

It does not appear that fires were divided into size classes, like in the previous WRAP 2018 projection methodology. That seemed to be a reasonable and accepted method to project wildfire into the future. Why was this approach not used?

Projection emission inventories were prepared per the methodologies described in detail in the report. The methodologies included the inclusion of realistically sizefires across the domain of the emission inventory. A statistical review of fire events in the projection inventorwould reveal that the distribution of fires per size class would be identical to the distribution of fires in the Phas(Baseline) and Phase II (historical 2002) fire emisison inventories.
APPENDIX D 

EPA Proposed SCC Codes 
WRAP Fire Ph3-4 EI Report_20070515.doc D-1

Comparison of Phase II and Baseline (2000-2004) Inventories

Non-Federal Rangeland Acres Burned and PM2.5 Emissions

0

50,000

100,000

150,000

200,000

250,000

300,000

Acres or Tons

Phase II Rangeland Acres 0 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000

Baseline Rangeland Acres 0 250,001 40,000 12,000 8,000 150,001 25,000 60,000 1,000 300,001 150,001 25,000 6,000 15,000

Phase II Rangeland PM 2.5 0 3,708 593 178 119 2,225 371 890 15 4,449 2,225 371 89 222

Baseline Rangeland PM2.5 0 3,708 593 178 119 2,225 371 890 15 4,449 2,225 371 89 222

AK AZ CA CO ID MT ND NM NV OR SD UT WA WY
WRAP Fire Ph3-4 EI Report_20070515.doc D-2

Proposed EPA SCC Codes & Codes for any Future RPO EIs WRAP Phase II SC

SCC Code Status SCC Name (L3/L4) SCC Fire Type 2610000500 Clarify Name 

Construction, Land Clearing Debris & Other / (Non logging) Unspecified burn method (Note: Use 2810005000 for slash and logging-related debris burning) 

N/A 

2810005000 Clarify Name 

Managed Burning, Slash (Logging Debris) / Unspecified burn method (Note: Use 2610000500 for non logging (e.g., 

construction)-related debris burning) 

N/A 

2810001000 Clarify Name Wildfire / Unspecified fire stage, class/purpose, ownership 2810001000 Wildfire 28100010F0 New Wildfire / Flaming, Unspecified class/purpose, ownership 2810001000 Wildfire 28100010S0 New Wildfire / Smoldering, Unspecified class/purpose, ownership 2810001000 Wildfire 2810001001 New Wildland Fire Use / NATURAL (Maintenance), unspecified fire stage, ownership 2810001001 Wildland Fire Use (W28100010F1 New Wildland Fire Use / Flaming, NATURAL (Maintenance), unspecified, ownership 2810001001 WFU 28100010S1 New Wildland Fire Use / Smoldering. NATURAL (Maintenance), unspecified ownership 2810001001 WFU 2810001002 New Wildland Fire Use / ANTHROPOGENIC (Restoration), unspecified fire stage, ownership 2810001002 WFU 28100010F2 New Wildland Fire Use / Flaming, ANTHROPOGENIC (Restoration), unspecified ownership 2810001002 WFU 28100010S2 New Wildland Fire Use / Smoldering, ANTHROPOGENIC (Restoration), unspecified ownership 2810001002 WFU 2810015000 Clarify Name Prescribed Forest Burning / Unspecified ownership, class/purpose 2810015000 Prescribed 2810015001 New Prescribed Forest Burning / NATURAL 2810015001 Prescribed 2810015002 New Prescribed Forest Burning / ANTHROPOGENIC 2810015002 Prescribed (USE in FU2810020000 Clarify Name Prescribed Rangeland Burning / Unspecified ownership, class/purpose NA 2810016001 New Prescribed Rangeland Burning / Non-Federal Rangeland NATURAL 2810016001 Non-Federal Rangelan2810016000 New Prescribed Rangeland Burning / Non-Federal Rangeland ANTHROPOGENIC 2810016000 NFR 2801500000 Clarify Name Agricultural Field Burning / Unspecified crop, class/purpose 2801500000 Agricultural 2801500001 New Agricultural Field Burning / NATURAL (Native American Fire Use) 2801500001 Agricultural 2801500002 New Agricultural Field Burning / ANTHROPOGENIC 2801500002 Agricultural (USE in F