Data
Measurement Quality Tables
To ensure that all FIA observations are made to the highest standards
possible, a regular program of quality control and quality assurance
is an integral part of all FIA data collection efforts. This program
begins with the documentation of protocols and procedures used
in the inventory followed by extensive crew training. To assess
the quality of the data collected by these trained crews, a random
sample of at least 4 percent of all plots are measured independently
by a different qualified crew. These independent measurements are
referred to as blind checks. The purpose of these blind checks
is to assess the quality of field measurements. The second measurement
on these blind check plots is done by a crew termed the QA crew.
In all cases, QA crews have as much or more experience and training
in FIA field measurements that those of the standard FIA crews.
The
quality of field measurements is assessed nationally through
a set of measurement quality objectives (MQO’s) that
are set for every data item FIA collects. Each MQO consists
of
two parts; a tolerance or acceptable level of measurement error,
and
an objective in terms of the percent of measurements within
tolerance. The blind check measurements are used to observe
how often individual
field crews are meeting these objectives and to assess the
overall compliance among all crews. The tables here report
the compliance
rates for various measurements on North Central Research
Station (NCRS) FIA phase 2 and phase 3 plots.
We have continued to refine the sample design and measurement
methods, and are moving towards incorporating the Phase 3 data
seamlessly into the core FIA program. In the near future, our
goal is to incorporate these data elements into all public
FIA databases, enabling our clients to access all field collected
FIA data. Until we achieve that integration, the data processing
for Phase 3 data elements occurs on a separate track from the
rest of FIA field data.
Phase 3 data collected under both the FHM program (1990 to 1999) as well as
FIA (from 2000 onward) is available as comma-delimited ASCII files or as SAS
6.12 data sets.
RPA Forest Resource Tables provide current information on
the Nation's forests. Resource tables present estimates of
forest area, volume, mortality,
growth, removals, and timber products output in various ways,
such as by ownership, region, or State.
The first set of preliminary tables from the 2002 National Woodland
Owner Survey are now available. The focus of much of the information
in these tables is family forest owners and, in particular, family
forests with total landholdings between 10 and 5,000 acres.
Both the new and old FIADB raw data files are compressed,
comma separated files,
and can be easily uploaded into
spreadsheets. Click
here for Documentation on FIADB formats.
These shapefiles use the RPA Summary DB format. Users can
easily load these shapefiles into geographic information system
(GIS) software.
These files are compressed, comma separated files, and
can be easily uploaded into spreadsheets.
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