Watershed 6 serves as the biogeochemical reference watershed within
the Hubbard Brook Experimental Forest.
GRID PLOT MAP and ELEVATION TABLE
Watershed 6 plots were established by a 25 x 25 meter slope-corrected
grid. A map of this grid is included in this data package. The grid
was surveyed in the 1960s. When measurements began, corner stakes were
labeled with an X-Y coordinate system. Grid cells with more than 50
percent of their area lying outside the watershed boundary were not
included and not staked. At the conclusion of the survey, the grid
cells (or "plots") were numbered consecutively from the top
left (west) of the watershed to the bottom. Each cell is now
identified by a numbered aluminum tag at the base of the NW corner
stake, and in some cases the old coordinates are also visible stamped
into the aluminum tag.
The elevation table reports elevation data for each grid corner. Plot
numbers designate the NW corner of a grid cell, so coordinates without
a plot number are the corners of outer grid cells which do not define
the NW corner of another cell. Slope and aspect apply to the entire
grid cell. Till depth was measured with a sonar device in the late
1960s or early 1970s.
ZONE MAPS
Elevation zones (or "sub-areas"):
For the purposes of many studies, the watershed was long ago divided
into the following arbitrary elevation zones of roughly equal area:
Upper = plots 1 – 86
Middle = plots 87 – 158
Lower = plots 159 - 208
Vegetation zones:
Forest community type for each plot can be divided into the following
vegetation zones:
1: The spruce/fir-dominated forest on the ridge;
2: The "high hardwoods"--this hardwood forest is at the same
general elevation as the spruce/fir but is dominated by beech, birch
and maple;
3: The central area of the watershed, mostly dominated by sugar maple
and beech;
4: The lower portion of the watershed on which the hardwood mix is
more equitable among the three major species.
Although vegetation zones are a somewhat more realistic division of
the watershed, we are left with the legacy of division by the
elevation zones outlined above. Depending on the particular study,
either one of these zonations might be used. For purposes of
comparison:
1 and 2 are roughly equivalent to "upper"
3 is roughly equivalent to "middle"
4 is roughly equivalent to "lower"
