ForestERA Metadata - Crown Bulk Density

Description

Abstract

This is a 90m resolution raster dataset describing crown bulk density across the western Mogollon Plateau in Arizona. It was created as part of the Forest Ecosystem Restoration Analysis (ForestERA) project to support landscape-scale forest restoration planning efforts by a broad group of stakeholders including federal and state agencies, academic institutions, and non-governmental entities.

Purpose

This layer was developed by the ForestERA project for use in landscape-level planning and prioritization of forest management on the western Mogollon Plateau. It was designed to be used primarily in fire behavior modeling and forest management planning. This layer, converted to ascii format, is ready for use in the FlamMap and FARSITE fire behavior modeling programs.

Supplementary Information

This layer was created using the basal area, tree density, and dominant overstory vegetation layers developed by the ForestERA team using Enhanced Thematic Mapper (ETM) imagery. Crown Bulk Density (hereafter CBD) cannot be directly measured using readily available types of remote-sensing imagery. Because of this, it was necessary to use allometric equations to develop the CBD layer. For the mixed-conifer, and ponderosa pine vegetation types we used equations developed by Cruz et al. (2003; International Journal of Wildland Fire 12: 39-50) that derive CBD directly from measurements of basal area and tree density. The same equations were used for mixtures of ponderosa pine with aspen or oak, and of mixed-conifer with aspen, as the coniferous component of these vegetation types is typically dominant. For pinyon-juniper woodlands and juniper-dominated woodlands we based CBD on percent canopy cover using the equation (CBD = percent canopy cover / 100). This methodology is a modification of the methodology used by Keane et al. (2000; USDA Forest Service General Technical Report RMRS-GTR-46-CD) to assign CBD values to pinyon-juniper woodlands in the Gila National Forest of New Mexico. Keane et al. and Pollard (1971; Canadian Journal of Forest Research 27: 27-33) suggested values of 0.01 for CBD in stands of pure quaking aspen and we followed their suggestion by assigning this value for CBD to aspen stands.

Accuracy assessment was undertaken using linear regression and data from forty-three 0.8 ha ground plots where basal area and tree density were measured directly. The results of this regression analysis indicated that a highly significant relationship exists between the two measures (r² = 0.601, P < 0.001). The slope of the line from this relationship is 1.01 indicating that the CBD estimates from the ETM derived layers are unbiased with respect to the estimates from the ground data.

Based on the differences between the values for CBD estimated from the ground data and the predicted canopy cover values in the ETM-derived layer, we have determined that values for over 50% of the estimated CBD values based on the ETM derived layers lie within 0.03 kg / m3 of the estimated values based on the ground data and over 80% of the estimated CBD values based on the ETM derived layers lie within 0.05 kg / m3 of the estimated values based on the ground data.

These data are intended for regional analyses over spatial extents on the order of tens to hundreds of thousands of acres, and were not developed for use at finer spatial scales, although they may be useful for some applications at those finer scales.

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Status of the data

Complete
Data update frequency: As needed

Time period for which the data is relevant

Date and time: 1997
Description:
publication date

Publication Information

Who created the data: Forest Ecosystem Restoration Analysis Project

Date and time: February 1, 2004
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Data storage and access information

File name: crownbulk90m
Type of data: raster digital data

Location of the data:

\\ENVSCI41\Shared\metadata_layers\grids\crownbulk90m
Data processing environment: Microsoft Windows 2000 Version 5.0 (Build 2195)
Service Pack 4; ESRI ArcCatalog 8.1.2.671

Accessing the data

Size of the data: 22.970 MB
Data transfer size: 22.970 MB

Constraints on accessing and using the data

Access constraints: This layer may be accessed by any interested party. It is
provided by the Forest Ecosystem Restoration Analysis project, the Ecological
Restoration Institute (ERI), and Northern Arizona University (NAU).

Use constraints:
This layer is provided for public use by the ForestERA project, ERI, and NAU.
Reports, presentations, and publications in which this layer is presented or
used for analytical purposes should acknowledge the ForestERA project.

Details about this document

Contents last updated: 20040421 at time 14313700

Who completed this document

Forest Ecosystem Restoration Analysis Project
Center For Environmental Sciences and Education:
Northern Arizona University
Flagstaff, Arizona 86011-5694
United States
928-523-0068 (voice)
928-523-7423 (fax)

Contact Instructions:

Contact Dr. Thomas D. Sisk or the Forest Ecosystem Restoraton Analysis Project.

Standards used to create this document

Standard name: FGDC Content Standards for Digital Geospatial Metadata
Standard version: FGDC-STD-001-1998
Time convention used in this document: local time
Metadata profiles defining additonal information
ESRI Metadata Profile: http://www.esri.com/metadata/esriprof80.html

Horizontal coordinate system

Projected coordinate system name: NAD_1983_UTM_Zone_12N
Geographic coordinate system name: GCS_North_American_1983
Details
Grid Coordinate System Name: Universal Transverse Mercator
UTM Zone Number: 12
Transverse Mercator Projection
Scale Factor at Central Meridian: 0.999600
Longitude of Central Meridian: -111.000000
Latitude of Projection Origin: 0.000000
False Easting: 500000.000000
False Northing: 0.000000

Planar Coordinate Information

Planar Distance Units: meters
Coordinate Encoding Method: row and column
Coordinate Representation
Abscissa Resolution: 90.000000
Ordinate Resolution: 90.000000

Geodetic Model

Horizontal Datum Name: North American Datum of 1983
Ellipsoid Name: Geodetic Reference System 80
Semi-major Axis: 6378137.000000
Denominator of Flattening Ratio: 298.257222
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Bounding coordinates

Horizontal
In decimal degrees
West: -113.044931
East: -109.878536
North: 35.587479
South: 34.107751
In projected or local coordinates
Left: 314687.387285
Right: 601607.387285
Top: 3938195.572581
Bottom: 3775925.572581
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Spatial data description

Raster dataset information
Raster format: ESRI GRID
SDTS raster type: Grid Cell
Number of raster bands: 1
Raster properties
Origin location: Upper Left
Has pyramids: FALSE
Has colormap: FALSE
Data compression type: Default
Display type: matrix values
Cell information
Number of cells on x-axis: 3188
Number of cells on y-axis: 1803
Number of cells on z-axis: 1
Number of bits per cell: 32
Cell Size
X distance: 90.000000
Y distance: 90.000000

No detailed attribute information is available.

Last updated February 11, 2005