Experimental Design of Bonanza Creek Experimental Forest
Introduction
The majority of the research being conducted at Bonanza Creek Experimental Forest is organized under
the Bonanza Creek Long-Term Ecological Research (LTER) program.
The Bonanza Creek LTER is currently in its third funding cycle. LTER 1, LTER 2 and
LTER 3 are
successive proposals to date. Bonanza Creek operates under LTER 3 but much of the research design for
core datasets originates from LTER 1 and LTER 2. We have just submitted
LTER2004 (reviewers see link for methods).
The LTER research program at Bonanza Creek Experimental Forest is
designed to study ecosystem structure and function through examination of controls over
successional processes in taiga forests of interior Alaska. This study tests hypotheses
under LTER1 and LTER2 in two successional sequences; three replicates each of six
successional stages of primary succession on the floodplain of the Tanana River and
three stages of succession following wildfire on south-facing slopes in the uplands.
Successional stages and turning points
We selected "turning points" in the succession sequences where, within a relatively short
interval, critical changes in ecosystem structure are accompanied by functional changes
which have far-reaching effects on ecosystem development. At six turning points in the
floodplain succession and three turning points in the upland succession three replicates
of experimental plots were established for experimental projects and to follow the natural
changes occurring in ecosystem structure and function.
Study site naming scheme and descriptions
Study sites at Bonanza Creek Experimental Forest are named according to the habitat, successional stage the site was at
when the site was established, and the replicate. There are two main naming schemes. In the first the site is described numerically.
An example would be site 231 where the 2 indicates a floodplain site, 3 indicates the third successional
stage and 1 indicates the first of three replicates. 112 would represent an upland site in the first successional stage and
the second of three replicates.
In the second naming scheme the sites are coded according to the following scheme: Habitat (FP=Floodplain, UP=Upland),
successional stage (numeric), replicate (A-C). An example using this scheme would be UP3B representing an upland, mid successional
site and the second of three replicates. FP5C would represent a floodplain site, advanced in successional sequence and the
third of three replicates. A table of the sites is shown below. Clicking on a site name will link you to our
study sites database.
Map of the plots
The physical layout of the experimental forest can be seen in our image map
Plot layout
At each of the sites in Bonanza Creek Experimental Forest a 50x60 meter permanent "control plot"
was established
to provide a control for experiments and to monitor vegetation change. Within each control plot
20 vegetation plots are measured.
Each vegetation plot consists of
a 1 m2 plot for measurement
of herb, lichen, moss, and low shrub cover estimates, and a 4 m2 plot for measurement of shrubs
and tree seedlings (vegplot.ai). In addition all trees and shrubs having a breast height
diameter of 2.5 cm or larger are tagged and mapped. Ten trees of each species within the
reference stand are also equipped with band dendrometers for measuring annual diameter growth
at breast height. In young successional stands the vegetation plots are monitored every two years;
in mature types they are monitored every five years. In addition, litter trays have been placed in
each reference stand and seed traps in one of each of the eight successional stages. At four points
around the perimeter of each reference stand the forest floor and mineral soil profile was described
and sampled using standard procedures. Bulk samples of both materials were obtained for physical
and chemical analysis. These assessments are repeated at 10-year intervals.
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