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PMS 437

Fuels: Canopy Fuel Characteristics

  1. Canopy Cover-Percentage or Class
  2. Stand (Canopy)-Height-ft or m
  3. Canopy Base Height-ft or m
  4. Canopy Bulk Density-kg/m3 or lb/ft3

Canopy Cover - Percentage or Class

The forest Canopy Cover (CC) describes the percent cover or cover class of the tree canopy in a stand. Specifically, CC describes the vertical projection of the tree canopy onto an imaginary horizontal surface representing the ground’s surface. Estimate of CC is used in adjustment of 20 feet winds to mid-flame, fuel moisture conditioning and spotting distance models.

The scale illustrates representative CC percentages and ranges within each cover class.

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Canopy Cover classification. This graphic depicts from above views of canopy cover and its effect on wind sheltering/reduction.

For surface fuels sheltered by a forest canopy on flat terrain. (Scott 2007)

Canopy Cover Wind Sheltering
CC ≤ 5% Unsheltered
5% < CC ≤ 10% Partially Sheltered
10% < CC ≤ 15% Partially Sheltered
15% < CC ≤ 30% Fully Sheltered, Open
30% < CC ≤ 50% Fully Sheltered, Open
CC > 50% Fully Sheltered, Closed

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Stand (Canopy) Height-ft or m

The Stand or Canopy Height (SH) describes the average height of the top of the vegetated canopy. SH estimates are used in adjustment of 20 feet winds to mid-flame and in spotting distance models.

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Canopy Base Height-ft or m

The forest Canopy Base Height (CBH) describes the average height from the ground to a forest stand's canopy bottom. Specifically, it is the lowest height in a stand at which there is a sufficient amount of forest canopy fuel to propagate fire vertically into the canopy. Using this definition, ladder fuels such as lichen, dead branches, and small trees are incorporated. Estimate of CBH is used in the Crown Fire Initiation model.

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Describing a Forest Canopy. This graphic highlights the way to think about the primary descriptors for crown fire prediction. Crown Bulk Density describes the crown fuel load and distribution. Stand Height describes height of canopy tops. Crown Base height represents the difficulty for surfaces fires to ignite the canopy. And Foliar Moisture content suggest how readily the canopy will burn.

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Canopy Bulk Density-kg/m3 or lb/ft3

The forest Canopy Bulk Density (CBD) describes the density of available canopy fuel in a stand. It is defined as the mass of available canopy fuel per canopy volume unit. Typical units are either kg/m3 (LANDFIRE default) or lb/ft3 (BehavePlus default). CBD estimates are used to determine the threshold spread rate, or surface wind speed, used to determine the likelihood of active crown fire.

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Canopy Bulk Density is a difficult concept to apply to crown fire predictions. This image shows that CBD varies with height above ground.

The following graph, also displayed in the Crown Fire section under Crown Fire Initiation and Propagation, displays the threshold surface 20 feet wind speed or Crowning Index, necessary for producing active crown fire given a specific canopy bulk density.

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Crowning Index. Based on Rothermel crown fire spread model, canopy bulk density can be related to the windspeed required to sustain crown fire.

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NWCG Latest Announcements

NWCG Equipment Technology Committee Releases New Equipment Bulletins

Date: September 27, 2024
Contact: Equipment Technology Committee

The Equipment Technology Committee (ETC) has released three new Equipment Bulletins:

  • ETC-EB-24-003 Diesel exhaust fluid (DEF) in fuel containers.
  • ETC-EB-24-004 Two-compartment fuel and oil container (Dolmar) unavailable in the United States (US) and reminders for upkeeping current inventories.
  • ETC-EB-24-005 Personal Protective Equipment (PPE): Inspection, Care, and Maintenance.

These bulletins remind field going personnel of important issues related to equipment for wildland firefighting efforts.

References:

NWCG Alerts

ETC-EB-24-003 Diesel exhaust fluid (DEF) in fuel containers

ETC-EB-24-004 Two-compartment fuel and oil container (Dolmar) unavailable in the United States (US) and reminders for upkeeping current inventories

ETC-EB-24-005 Personal Protective Equipment (PPE): Inspection, Care, and Maintenance

The Experiential Learning Subcommittee is looking for your feedback on Staff Rides

Date: September 20, 2024
Contact: Ashleigh D'Antonio and George Risko, Leadership Committee

The Experiential Learning Subcommittee needs to hear from the field about where the greatest need lies regarding staff rides and their accessibility.

  • Do you have an event you would like to turn into a learning experience?
  • Do you have a staff ride built, but are struggling to implement the delivery?
  • Do you need help building capacity?
  • What other ideas do you have to support experiential leadership training?

Fill out this short survey below to help us help you.

References:

Staff Rides: Feedback

Staff Rides

Updated NWCG Single Resource Casual Hire Information, PMS 934

Date: September 19, 2024
Contact: Incident Business Committee

The Incident Business Committee has updated the NWCG Single Resource Casual Hire Information, PMS 934. This update expands the provisions for hiring emergency personnel.

References:

NWCG Single Resource Casual Hire Information, PMS 934

IBC Memorandum 24-03

NWCG 2024 Spring/Summer Highlights

Date: September 13, 2024

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Welcome to our latest highlights from the National Wildfire Coordinating Group, where we explore the latest updates, insights, and efforts that develop interoperable wildland fire operations among federal, state, local, Tribal, and territorial partners.

The Performance Support Package, which for ABRO includes the Incident Position Standards and Next Generation Position Task Book were developed through the Incident Performance and Training Modernization (IPTM) effort. The Performance Support Package will support trainees, those qualified in the position, and evaluators.
 

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NASA JOINS NWCG!

The National Aeronautics and Space Administration (NASA) is officially an associate member of NWCG. As such, NASA is beginning to collaborate with wildland fire management agencies with the goal of increasing collaboration across agencies and leveraging NASA data, technology, and innovation for nation-wide efforts in wildland fire management. NASA has a rich history of research, development, and technology transfer in the areas of Earth science, space technologies, and aeronautics that support the NWCG mission.

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WWW.NWCG.GOV HAS A NEW LOOK AND DESIGN

The NWCG web team dedicated the past two years to making a significant upgrade to the www.nwcg.gov site. This upgrade involved a comprehensive redesign of over 7,700 web pages.

The modernization of NWCG’s website involved migrating to Drupal 10, a cutting—edge content management system, and leveraging Amazon Web Service GovCloud for secure and efficient hosting. These upgrades help ensure that the NWCG website remains current in content management practices, offering enhanced customization, improved performance, and an overall superior user experience.

NWCG Leadership Committee

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The Wildland Fire Leadership Development Program announced the Professional Reading Program’s 2024 list!

The years books include:

  • Young Men and Fire by Norman Maclean
  • The Wisdom of the Bullfrog by William H. McRaven
  • The Art of Clear Thinking by Hasard Lee
  • Emotional Agility by Susan David
  • Writing to Persuade by Trish Hall

Learn more at the NWCG Leadership Committee

INCIDENT PERFORMANCE AND TRAINING MODERNIZATION

In 2023, NWCG kicked off the Incident Performance and Training Modernization (IPTM) effort. A training system overhaul focused on developing a performance-based training system designed to shift training to on-the-job when appropriate.

Over the next five years, NWCG intends to analyze all positions within the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1. To date we are currently working on 30 incident positions, and planning for 20+ in calendar year 2025.

Subject Matter Experts from a variety of geographical areas and agencies recently completed the position analysis for 16 positions. From this analysis, Incident Positions Standards and a Next Generation Position Task Book will be developed for each position.

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Incident Performance and Training Modernization

NEXT GENERATION POSITION TASK BOOK

In April 2024, NWCG launched the new Next Generation Position Task Book (Next Gen PTB) which is a key component of the IPTM effort. This revised evaluation tool is designed to work in conjunction with the newly developed Incident Position Standards.

Major Next Gen PTB changes:

  • Structured to improve constructive conversations between evaluators and trainees.
  • Reference new Incident Position Standards.
  • Include only tasks required to be evaluated for successful performance.
  • Trainees will be rated on their performance vs. initialing whether a task was completed.
  • Must include written feedback when trainee does not meet the standard.
  • Will be position specific (no combined PTBs).
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NWCG’s training course catalog is now available on the Wildland Fire Learning Portal (WFLP).

To access the training course catalog, visit WFLP and either set up an account or login as a guest.