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Global Change Master Directory (GCMD)
Forest Floor Fuel Estimates for the Eastern United States
Entry ID: USDA_forestfloorfuelestimates

Abstract: Foresters commonly separate forest floor or down woody materials (DWM) into
three successive layers: (1) branches and logs (fine and coarse woody
material), (2) litter, and (3) duff. Additionally, live and dead understory
shrubs and herbs are included with forest floor measurements. Duff includes
the dark, partly decomposed organic material (where plant forms are
unrecognizable) above mineral soil. On top of duff is litter, which includes
recognizable plant parts such as leaves and flowers but not branches. Branches
are separated into three size classes of fine woody material (FWM): <6, 6 to
25, and 26 to 76 mm in diameter. These classes correspond to 1-hour, 10-hour,
and 100-hour fire fuel classes, respectively. Coarse woody material (CWM)
includes all logs >76 mm in diameter and corresponds to the 1000-hour fuel
class. The US Department of Agriculture Forest Inventory and Analysis (FIA)
program currently measures variables related to DWM on a Phase 3 (P3) subsample
of its Phase 2 (P2) plots. We used P3 and P2 FIA data to estimate DWM for all
plots in the eastern half of the FIA database. First we acquired, compiled,
and computed mass on CWM, FWM, litter, duff, and shrub/herb cover from
different data sources, then we developed regression models to predict DWM
components for extension to almost 100,000 eastern FIA plots. The models for
estimating DWM for all FIA plots produced rather weak correlations to several
climate and dead-tree variables, and these results could only be improved with
modification of FIA field procedures. Average fuel mass for the eastern US are
6.0, 6.1, 5.3, 9.6, and 1.3 Mg/ha for CWM, FWM, litter, duff, and shrub/herb
cover, respectively. The total of all DWM components for the eastern US is
approximately 2,000 Tg or 17% of the total forest biomass, which includes 9,000
Tg live and 500 Tg dead biomass in standing trees.

The purpose behind the development of this dataset is a regional-scale estimate
of down woody materials that contribute to prescribed and wildland fire fuels.
After developing accurate models of down woody materials by fuel class,
location, and other forest attributes, we will then link the models to PEcon, a
species-level forest growth and economics model, to predict down woody
materials and fuel loads in response to changes in climate, land use, species
composition, and timber markets.

Related URL
Description: Metadata in Biological Data Profile format.

Geographic Coverage
 N: 47.35 S: 25.0  E: -66.95  W: -106.65

Data Set Citation
Dataset Creator: USDA Forest Service, Southern Global Change Program
Dataset Title: Forest Floor Estimates for the Eastern United States
Dataset Publisher: U.S. Department of Agriculture

Temporal Coverage
Start Date: 2001-01-01
Stop Date: 2002-12-31

Location Keywords

Science Keywords

ISO Topic Category

Residuals for the separate DWM class estimates are available with the dataset.

Chojnacky, D.C., Mickler, R.A., Heath, L.S., Woodall, C.W. 2004. Estimates of
down woody materials in eastern US forests. Environmental Management
33(Supplement 1): S44-S55.

Access Constraints
P2 and P3 are available to the public via the national FIA Program web
repository: Modeled DWM
estimates are not accessible until after publication.

fire behavior
forest floor
understory shrubs
fire fuel class
southeastern United States

Data Set Progress

Data Center
Southern Global Change Program, Southern Research Station, Forest Service, Department of Agriculture    [Information]
Data Center URL:

Data Center Personnel
Contact Address:
920 Main Campus Drive, Suite 300
City: Raleigh
Province or State: NC
Postal Code: 27606

Phone: 919.515.2916
Email: mgavazzi at
Contact Address:
920 Main Campus Drive, Suite 300
City: Raleigh
Province or State: NC
Postal Code: 27606
Country: United States

2001, Wildfire Risk in the Eastern United States -- NFP 01.SRS.C.1
Geospatial Data Presentation Form: report
FRAMES resource id =

Chojnacky, D.C., S.G. McNulty, J.A. Moore Myers, and M.K. Gavazzi
Estimating forest floor fuels in eastern US forests --
Presented at EastFIRE Conference. Fairfax, VA, May 2005.

This publication is available online at

Chojnacky, D.C., R.A. Mickler, and L.S. Heath
2001 and 2002 Down Woody Materials P3 Data for Eastern U.S. Forests --
{38A73EBB-3AD8-48E0-9C51-27732EE7B180}, poster;
10th Annual Forest Health Monitoring Working Group Meeting. Sedona, AZ,
February 2004.
This publication is available for download at: from the USDA Forest Service
National Forest Health Monitoring Program at

Chojnacky, D.C., R.A. Mickler, L.S. Heath, and C.W. Woodall, 2004
Estimates of Down Woody Materials in Eastern US Forests --
Environmental Management 33 (Supplement 1): S44-S55.
This citation documents the dataset.
available for download through SpringerLink at website below:

Chojnacky, D.C., T.M. Schuler2004
Amounts of down woody materials for mixed-oak forests in Kentucky,
Virginia, Tennessee, and North Carolina --
Southern Journal of Applied Forestry 28(2): 113-117.
This citation documents the dataset.

This publication is in the Tall Timbers Fire Ecology Database but is available
through the Society of American Foresters at

Chojnacky, D.C., R.A. Mickler, and L.S. Heath
Carbon in Down Woody Materials of Eastern U.S. Forests --
Geospatial Data Presentation Form: Conference proceedings
Second Annual Conference on Carbon Sequestration. Alexandria, VA, May 2003.
This publication is available through the Second Annual Conference on Carbon
Sequestration website at -- pdf file
may be downloaded

Chojnacky, D.C., R.A. Mickler, and L.S. Heath
Biomass in Down Woody Materials of Eastern US Forests --
Geospatial Data Presentation Form: annual meeting talk
88th Ecological Society of America Annual Meeting. Savannah, GA, August 2003.

Chojnacky, D. C., L.S. Heath, 2002
Estimating Down Deadwood from FIA Forest Inventory Variables in Maine --
Environmental Pollution 116: S25-S30.
This citation documents the dataset.
This publication may be obtained from the Southern Research Station at or at

Chojnacky, D.C., R.A. Mickler, and L.S. Heath
Monitoring Down Woody Materials in Eastern U.S. Forests --
Conference proceedings
International IUFRO Conference on Monitoring and Indicators of Forest
Biodiversity in Europe--From Ideas to Operationality. Florence, Italy, November
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 2005-12-29
Last DIF Revision Date: 2017-08-23