Filename: SUBP94.DBF

About the Forest Health Monitoring (FHM) Program:
The FHM program is managed by the USDA Forest Service (FS) in
cooperation with other program participants. Funding comes largely from
the FS and the U.S. Environmental Protection Agency.  Other participants
include State Forestry and Agriculture agencies, the USDI Bureau of Land
Management, the Tennessee Valley Authority, the USDA Natural Resources
Conservation Service, and several universities. The National Association
of State Foresters provides essential program support, guidance, and
assistance. Detection Monitoring, the most extensive of FHM's three
monitoring activities, is designed to provide data to determine baseline
or current conditions of forest ecosystems, and to detect changes and
trends over time. This information is analyzed to determine if detected
changes are anticipated, and if those changes indicate improving forest
health or are cause for concern, warranting additional evaluation.
Detection Monitoring covers all forested land and has two components:
(1) the on-frame component, which is measurements made on the FHM
network of permanent plots; and (2) the off-frame component, which is
forest surveys made off of the FHM plot network and includes forest
insect, disease, and other stressor effects. (References: The Forest
Health Monitoring National Brochure, and the FHM Fact Sheet Series.
Available at the Forest Health Monitoring National Office, P.O. Box
12254, Research Triangle Park, NC, 27709)

Coverage:
FHM uses the EMAP sampling grid, which is formed from a triangular grid
of sampling points. The FHM ground plots are approximately 1-hectare in
size and contain 4 subplots approximately 1/60 hectare in size. Ground
plots are approximately 27 km apart. (Reference: Stevens, D.L. 1994.
Implementation of a national monitoring program. J. Environ. Manage.
42:1-29.)

About the Index/Measurements:
These data were collected in 1994. There are four records for each
hexagon; one SUBTERRAIN code for each of four subplots per hexagon.
Subplots are not necessarily in numeric order.

Complete information about the measurements can be found in the Forest
Health Montioring Field Methods Guide (Tallent-Halsell, N. (editor).
1994. Forest Health Monitoring 1994 Field Methods Guide. EPA/620/R-94/027. U.S. Environmental Protection Agency, Environmental Monitoring
Systems Laboratory, Las Vegas, NV.).

Definition of Data Set Variables (in the order they appear in the data
set):

HEXAGON_NB -   the unique 7-digit code assigned to each 40 km2 hexagon.

SUBTERRAIN -   This is the position of the subplot in relation to the
               surrounding topography.
  Code Definition
  1    Top and upper slopes - convex region on the upper part of the
       slope profile; may be either xeric or mesic depending on
       aspect.
  2    Midslope - uniform, fairly straight region of the middle part
       of the slope profile; may be either xeric or mesic depending on
       aspect
  3    Bench - area of level terrain, with midslope above and lower
       slope below.
  4    Lower slope - concave region on the lower part of the slope
       profile.
  5    Flatland - level or near-level terrain not part of or related
       to major elevational change; may have minimal elevational
       change (e.g., rolling uplands, flatwoods, deep sands).
  6    Bottomland - level terrain; normally well drained but subject
       to occasional flooding (e.g., flood plains of rivers and
       streams
  7    Wet bottomlands - level terrain; generally having year-round
       abundance or over abundance of water (e.g., swamps, small
       drains, bays, and wet pocosins.