|The PHACE project uses liquid CO2, stored in a 100,000 gallon refrigerated tank located near the field trailer.||
The PHACE trailer houses the electronics for the CO2 control system and the dataloging computer.
|A series of computer controlled valves injects CO2 to 10 elevated plots based on feedbacks of plot CO2 concentration and wind speed.||
A sonic anemometer relays wind-speed data to the CO2 control system.
Inside of the PHACE trailer with CO2 control system on the wall.
|Each of the 30 PHACE plots is isolated from the off-plot soil with a heavy plastic flange buried to 60 cm.|
|The thick plastic flange prevents water and roots from entering or leaving the actual plot below-ground area.||A line trencher was used to dig a hexagon shaped trench around all 30 plots, for the plot-soil-isolation flange.|
|Each of the 30 PHACE plots has a soil water profile (Sentek) sensor installed to 80cm depth which constantly records volumetric water content.||Each of the 30 PHACE plots has a minirhizotron tube installed at 25o and to ~52cm depth. The minirhizotron camera takes photographs of roots at ~1cm depth intervals.|
|RootTracker software is used to measure root lengths, widths and branching.||Installing minirhizotron tubes using a large auger, power drill and custom angle brace.|
|Plot soil water content, air and soil temperature are continually recorded using dataloggers and multiplexers.||10 plots are injected with pure CO2 through a pipe lined with laser-drilled holes to 600ppm. An infra-red gas analyzer constantly monitors CO2 concentration at the center of the plot and sends this data to the CO2 control system in the field trailer.|
|The infra-red gas analyzers are mounted near the elevated CO2 plots. All wires and cables are housed in PVC conduit for protection from weather and animals.||10 of the PHACE plots are warmed 1.5oC during the day and 3oC at night using 6 infra-red heaters mounted above the plots.|
|Warming is controlled by measuring plot temperature with an infra-red radiometer and constantly relaying this data to a computer controlled PID feedback system.||The plot warming control system uses the infra-red radiometer inputs from control-temperature plots to vary the electrical current level to the IR heaters on the warmed plots.|
|A close-up of one of the 6 infra-red heaters that surround the warmed plots.||To avoid damaging vegetation and sensors, plots are accessed from platforms which do not touch the plot area.|
|10 of the 30 PHACE plots are treated with either a deep-spring supplemental watering or frequent shallow-irrigations through the growing season. Water has to be trucked from a nearby water source.||Control CO2 and control temperature plots have the same 'infrastructure' as elevated CO2 and warmed plots to compensate for unintended effects of infrastructure.|
|Warming treatment plots are warmed year round, even during the winter.||Summer vegetation harvest, clipping crew must sit on planks in order not to smash the plot.|
|2008 Harvest Crew||A view from above heated plot|
|Measuring weed responses to elevated CO2 and temperature||Platforms prevent damage to the PHACE plants|
|A warmed, ambient CO2 plot||Collecting trace gace samples on the PHACE plots|
|Using the minirhizotron camera to take photographs of roots||June vegetation 2008|
|Jack Morgan gives a presentation at the Global Change in Western Rangelands symposium, September, 2008 in Cheyenne, WY.||PHACE site field tour for the Global Change in Western Rangelands symposium.|
|Participants of the Global Change in Western Rangelands symposium visit PHACE plots.||Dr. Dana Blumenthal discusses invasive weed research at the Global Change in Western Rangelands symposium PHACE tour.|
|Dr. Jack Morgan discusses ecology research at the Global Change in Western Rangelands symposium PHACE tour.||Dan LeCain and David Smith discuss the CO2 and Warming systems at the Global Change in Western Rangelands symposium PHACE tour.|
|Participants of the 41st Annual Air Pollution Workshop tour the PHACE site with Dan LeCain in April, 2009.||CSU graduate students tour the PHACE project in September 2012|