Arson burn on LTER-I Transect plant line intercepts - field data (tape format)

LTER-I Transect plant line intercept data. This data set is as
transcribed (UNSORTED) from cassette tape with one intercept
observation per record.

Data consist of week number, transect, station, segment number,
plant species, and length of species intercepted by line stretched
between 2 rebar the length of the 30 meter plant line intercept transect.

Measurements are made on 30-meter line intercept transects located
perpendicular to each of 91 stations on each of the 2.7 km long
Control, Treatment, and Alternate Control Transects established at
the beginning of LTER-I. Each plant line transect is divided into 6
5-meter segments. Annuals are measured only in the first meter of
segments 1, 2, and 3 and in the last meter of segments 4, 5, and 6.
Perennials are measured for the full length of all segments.

On March 19, 2000, an arson burn occurred of 2.5 acres of the upper
grassland area on the Summerford bajada just below the powerline
road. The area affected included portions of the LTER-I Transect
Plant Line Intercept study that was begun in 1982. To evaluate the
impact of the burn on those lines, the line intercepts were read
for the upper grassland area extending from immediately above the
creosotebush fringe to the base of Summerford Mountain. The
stations measured were C73-C89, T75-T90, and X76-X91 (Control,
Treatment, and Alternate Control, respectively). Measurements were
made immediately after the burn, after the spring growing season,
and after the fall growing season in 2000 only. In the initial
sampling period, the burn area intercepted by the line was noted in
the data set using a "species" code of BURN.

BACKGROUND.
In the spring of 1982, as part of the establishment of
the Jornada Long-Term Ecological Research site in southern
New Mexico, a 135 ha portion of a 1500 ha, internally
drained, watershed was exclosed from grazing by domestic
livestock. Prior to exclosure the watershed, as well as the
rest of the Jornada basin, had been moderately to heavily
grazed for the past 100 years. Concurrent with grazing, the
vegetation had undergone a dramatic change from desert
grassland, with an almost continuous cover of C4 perennial
grasses, to isolated patches of the original grassland in a
mosaic with desert shrub dominated plant communities
(Buffington and Herbel, 1965).
The exclosure lies along a northeast facing piedmont
slope at the base of a steep isolated mountain peak, and
covers a variety of component landforms from the foot of the
mountain to the basin floor. This provided the opportunity
to investigate the response of vegetation with respect to
landscape characteristics as well as release from grazing.