Transcript Building the Rhizotron - Northern

Background
Belowground Forest Management
-our forest management to date has
been largely based on what we see
aboveground not what we see
belowground--
Tree roots and other life in forest soils provide valuable
ecosystem services such as:
•Water and nutrient supply to trees, resulting in healthy and
productive forests
•Carbon storage to help slow the accumulation of
atmospheric CO2 –a potent greenhouse gas
•Beneficial and pathogenic soil organisms
•Structure to support trees and prevent soil erosion
•Restoration of compacted or degraded soil
•Water purification and toxin removal for soil, surface water,
and ground water
•Beneficial and antagonistic tree root system interactions
which impact forest productivity.
The Houghton Rhizotron will enable us to better understand the environmental
controls and management impacts on these services by providing a research
facility that enables repeated non-destructive access to forest soil as it really is in
nature.
Site Selection
The Rhizotron facility is located at the Forest
Service’s Northern Research Station, Forestry
Sciences Laboratory in Houghton, Michigan.
A site was chosen near the existing laboratory
facilities on the Michigan Technological University
campus to provide easy access for researchers.
This facility is one of two in the world located in a
northern forest ecosystem. The site is dominated by
white ash and sugar maple trees.
Test pits were dug in various locations to locate a
suitable site. At the chosen location the upper 27
inches of native soil was classified as a loamy sand.
The native soil from 27-67 inches below land surface
was classified as a sand. Basalt rock was also
encountered.
Groundbreaking
June 2005
The Groundbreaking
ceremony was held on 14
June 2005. Shown are (from
left) David Reed, Dale
Tahtinen, Peg Gale, Dan
Greenlee, Glen Mroz, Kurt
Pregitzer, Mike Henricksen,
Alex Friend, Christian
Gardina, Ruth Gleckler, Noah
Karberg, Erik Lilleskov, and
Martin Iskra.
Excavation
July 2005
Excavation began in July, 2006. It was anticipated that
bedrock would be encountered and that blasting would be
necessary. However, all rock encountered was able to be
broken up with the excavator. Tree roots even found their
way through this soft rock!
Excavation was completed to an average depth of about 9
ft. Sheet pilings were used on the east side of the
excavation so that the Rhizotron could be built as close as
possible to the undisturbed soil on this side.
Construction
The Rhizotron facility was constructed with a
2 foot gap between the undisturbed soil and
the east side of the building. A drain was
installed along the foundation to help prevent
unnatural water buildup along the facility wall.
August 2005
24, 60 x 40 inch windows were installed along
the length of the facility. The entire facility was
slanted to follow the natural slope of the land.
Construction
15 panels of steel reinforced glass
were installed in each of the 24
windows. The panels were designed
to so that they may be individually
removed for manipulative studies. The
glass is sealed against the elements
using an organism-friendly aquarium
sealant.
August 2005
The walls, floor and ceiling of the Rhizotron were
constructed of steel reinforced concrete. A head house
was constructed for storage of supplies, records, and
experimental preparatory work.
Backfill
Backfill of the excavated areas adjacent to
the Rhizotron was designed to emulate
natural stratigraphy.
The east side of the facility was backfilled
using the same material that was excavated.
This material had been stockpiled according
to soil type as it was removed. Backfill was
conducted to emulate local conditions.
November 2005
The west side of the facility was backfilled
with a sandy soil from a red pine forest. It was
donated by Plum Creek Timber Company
from a site in Atlantic Mine, MI. Backfill was
conducted to emulate the soil layers in the
forest of origin.
Backfill was watered as it was placed as a
natural means of compaction. Fill material
was brought just up to the top of each
window.
Finish Work
The exterior of the facility was finished with
metal siding and a brick retaining wall. White
Pine, Aspen, Sugar Maple, Norway Maple, and
Buckthorn tree seedlings were planted on the
previously excavated areas.
June 2006
Each window was fitted with a stainless steel
cover to prevent light pollution while working in
the facility. Interior lighting includes fluorescent
tubes and photographic dark room lights to
permit observation and image capture of
photosensitive organisms. A climate control
system was also installed to keep the open
space at ground temperature.