Vegetation Classification and Mapping Project Report - USGS

1 Introduction
1.1 Background
Vegetation is a primary resource of natural
areas, and description of vegetation
composition, structure, and distribution is
fundamental to effective land management.
The term “vegetation” encompasses
plants at multiple scales, from the most
refined floristic levels (referred to as
“plant communities” in this report) to
the broadest physiognomic or life-form
levels. This report describes the methods
used and results obtained from a four-year
project (2003-2007) to classify, describe,
and develop a vegetation map database for
Petrified Forest National Park (PEFO).
The National Park Service’s (NPS)
Southern Colorado Plateau Network
(SCPN), part of the service-wide
Inventory and Monitoring (I&M)
Program, organized and coordinated
vegetation classification, description,
and mapping at PEFO. For PEFO as well
as its other 18 network parks, the SCPN
needed baseline vegetation data upon
which to develop and implement specific
monitoring programs. Park managers
needed baseline data and information on
park resources for management purposes.
In addition to the NPS, the project
team included members from the U.S.
Geological Survey (USGS) Southwest
Biological Science Center (SBSC),
Department of Geography at Kansas
State University (KSU), Northern Arizona
University (NAU), and NatureServe. The
USGS-NPS Vegetation Mapping Program
partially funded the project, and the
project team used the Vegetation Mapping
Program’s programmatic standards.
1.2 Scope and Products
The scope of this project was Petrified
Forest National Park and its environs,
consisting of an approximately 1-km buffer
around the 2003 park boundary. The total
project area was 53,201 ha (131,463 ac);
lands within the park boundary comprised
38,057 ha (94,042 ac) or 71.5% of the
project area.
A major goal of the project was to identify
and classify plant communities at the park,
based on field-collected vegetation data
and, to a lesser extent, observations made
during fieldwork conducted in association
with photointerpretation. First, the
project team identified and quantitatively
described plant communities using the
National Vegetation Classification System
(NVCS) as a classification framework.
The term “plant communities” refers
to the finest floristic levels of the NVCS
(associations and alliances) and to park
specials (i.e. plant communities with
insuffcient data to describe them as new
alliances or associations) for some stands
(table 1).
Second, the team created a spatial database
(the vegetation map database)
documenting the park’s vegetation and
land cover. The vegetation map database
represents four map class schemas (table
1):
1. the “base” map class, the finest level of
floristic detail that could be mapped
2. the “group” map class, a physiognomicfloristic
view of the vegetation
3. the “management” map class, park-defined
groupings of base map classes to
represent a balance between required
accuracy and maintaining map classes
of management concern
4. the “macrogroup” map class, aggregation
of group map classes to represent
the next higher level of the NVCS
hierarchy
Finally, we assessed each map-class
schema for accuracy. The base, group,
and macrogroup map classes were not
changed, but the management map classes
were refined following a meeting with park
resource staff.
This report and its appendices document
the methods, results, and findings for
the PEFO vegetation characterization
and mapping project. The project has
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