Vegetation Classification and Mapping Project Report - USGS

Executive Summary
The classification and distribution
mapping of the vegetation of Petrified
Forest National Park (PEFO) and
surrounding environment was completed
through a multi-agency effort between
2003 and 2007. The National Park
Service’s Southern Colorado Plateau
Network facilitated the team that
conducted the work, which comprised
the U.S. Geological Survey’s Southwest
Biological Science Center, Kansas State
University, Northern Arizona University,
and NatureServe.
The project team described 39 plant
communities for PEFO; 38 of which were
described from quantitative classification
based on field-relevé data collected in 1996
and 2003. The team derived one additional
plant community from field observations
during the photointerpretation phase
of the project and field documented it
during accuracy assessment. The National
Vegetation Classification Standard served
as a conceptual framework for assigning
these plant communities to the alliance
and association level. Seven of the thirtynine
plant communities were designated
“park specials”; that is, plant communities
with insuffcient data to describe them as
new alliances or associations.
The project team also developed a spatial
vegetation map database representing
PEFO, with four different map-class
schemas: base, group, macrogroup,
and management map classes. The
base map classes represented the finest
level of spatial detail. Initial polygons
were through manual interpretation
of 2003/2004 1:6,000 true color
aerial photography supplemented by
occassional computer screen digitizing on
a mosaic of digitized aerial photos. These
polygons were labeled with base map
classes during photointerpretation. Field
visits verified interpretation concepts.
The vegetation map database includes
● 46 base map classes, which consist of
associations and park specials classified
with the quantitative analysis
● one additional association noted during
photointerpretation
● non-vegetated land cover, such as infrastructure,
land use, and geological land
cover.
The base map classes consist of 6,989
polygons in the project area. A field-based
accuracy assessment of the base map
classes showed the overall accuracy to be
40.6%.
The group map classes represent
aggregations of the base map classes,
approximating the group level of the
National Vegetation Classification
Standard (NVCS), version 2 (Federal
Geographic Data Committee 2008).
Terrestrial ecological systems, as described
by NatureServe (Comer et al. 2003),
were used as a first approximation of the
group level. The project team identified
15 group map classes for this project. The
overall accuracy of the group map classes
was determined using the same accuracy
assessment data as for the base map
classes. The overall accuracy of the group
representation of vegetation was 55.7%.
The next higher level of the NVCS, the
macrogroup, was also used to develop
a map class schema. The project team
identified 13 macrogroup map classes.
The overall accuracy of the macro group
representation of vegetation was 73.5%.
In consultation with park staff, the team
developed management map classes,
consisting of park-defined groupings of
base map classes intended to represent
a balance between maintaining required
accuracy and providing a focus on
vegetation of particular interest or import
to park managers. The 24 management
map classes had an overall accuracy of
68.6%.
While the main products of this project
are the vegetation classification and the
vegetation map databases, a number of
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