Marcell Experimental Forest
This location is known as the Northern Research Station and is operated by the USDA Forest Service. This location, centered in the image above, is within the George Washington National Forest in Itasca County just 25 miles north of Grand Rapids, MN. The massive amount of lakes and wetlands in this region make up the headwaters that creates the Mississippi River. The Marcell Experimental Forest has a large historical database including underground temperatures of various environments down to 200cm below ground and taken weekly since 1989.
Temperatures were analyzed at four bogs and fens, one open upland imaged above, and a 100 year-old Upland Aspen Forest in it's second growth, meaning it's no longer impacted by the logging that occurred in this region. The coordinates for this location are 47.53 Latitude and -93.47 Longitude, and more information about this location can be found at the Marcell Experimental Forest Site.
Temperatures were analyzed at four bogs and fens, one open upland imaged above, and a 100 year-old Upland Aspen Forest in it's second growth, meaning it's no longer impacted by the logging that occurred in this region. The coordinates for this location are 47.53 Latitude and -93.47 Longitude, and more information about this location can be found at the Marcell Experimental Forest Site.
Temperature data in this graph is from 1989 through 2000. The red in the upper graph is the increased temperatures recorded in the open upland above the levels in the forest. This displays the increased thermal conduction due to this conversion resulting in greater temperatures, and this will have an immediately impact on surface temperatures and seasonal length. The lower graph is the the amount of heat gain the forest has above the open upland, this only occurred on a few occasions. The average temperature of the Upland Aspen Forest at -200cm from 1989 to 2017 was 43.5F, while the Open Upland was 45.9, a 2.4F temperature rise.
The National Weather Service sets the standards for surface temperature measurements and can be seen here at the National Weather Service. "Over level terrain (earth or sod) typical of the area around the station..." Nearby brush and the shade of the forests can decrease the temperature readings meaning that the air temperatures we monitor are not the natural temperatures, but the temperature adjusted for human habitat.
The National Weather Service sets the standards for surface temperature measurements and can be seen here at the National Weather Service. "Over level terrain (earth or sod) typical of the area around the station..." Nearby brush and the shade of the forests can decrease the temperature readings meaning that the air temperatures we monitor are not the natural temperatures, but the temperature adjusted for human habitat.
Isolating 1994 and the seasonal shifts demonstrates how the thermal conduction alters between these environments. After the frost is out of the ground but before the spring bloom, the surface thatch protects the soil and maintains the moisture prior to the spring bloom. The spring bloom shades the surface soils and microbial decay of the surface thatch becomes amplified with the warming days fueling the vegetating with CO2. At night, the deep rooted vegetation is able to amplify the discharge as a result of the hot summers day through transpiration maintaining a cooler subsoil temperature than converted land. Converted land increases thermal conduction resulting in an increase in thermal capacity and carries this additional heat throughout the winter months as the graph demonstrates. As every season passes there is a slow rise in subterranean heat resulting in an alteration in the thermal gradients as the gain becomes greater than its loss. Although the thatch in the fall maintains a warm environment allowing the temperatures to draw closer together, additional heat gain continues throughout the winter, but at a stable rate as the snow evenly protects both soils.
Due to a lightning strike, data was not available from September of 1999 to June of 2001. This data set begins with the new probe and the data appeared to be normal for 3 years when an alteration occurred. The bare plot began to show increased signs of oscillation and temperatures in the region were showing signs of cooling compared to the forest. Underground water can alter the temperatures, and with the amount of water in this region, this is expected. The Mississippi River Flood of 2011 is demonstrated as a cooling period for both probes in 2011 and demonstrates the impact subterranean water has on sub-soil temperatures. At the Mississippi Valley Traveler the following was reported, "May 26, 2011. I’m in Grand Rapids, Minnesota, in the Headwaters region, and the river is high enough to flood a few low-lying roads. In St. Louis, the river is expected to peak a few feet above flood stage again this weekend. Meanwhile, we all know what’s going on with the record flooding along the Lower Mississippi. What’s remarkable to me is that each of these sections is really a different river; flooding on one stretch has only minimal impact on the water levels in other stretches. Yet, here we are in spring 2011 with flooding along these very different parts of the Mississippi River. I don’t know what that means, but it sure is interesting."
Oscillation in subterranean temperatures in this region are not uncommon due to the water levels and elevation, so they can vary from season to season. These variations in temperatures never occurred since recording began in 1989 through the fall of 2004 after May 4th, or before August 26th in the upland readings. in 2004, the oscillation began to come later in the spring and earlier in the fall until July 11, 2007, for the first time, a heat pulse was recorded during the summer. Additionally, there is a greater variation in temperature oscillations being recorded. In 2005 oscillations above their normal variations were first picked up on the 1,280cm probe at the St. Paul Climate Observatory. With hourly recordings and sensitivity down to .01C, picking up this fluctuation would be identified earlier in St. Paul. In 2007 both locations recorded marked changes.
Marcel Experimental Forest compared to Swan Lake Research Farm
Both Swan Lake and Marcel Experimental Forest have identical depth measurements of 100cm and 200cm in depth. Swan lake is much further south so a delayed turnover in the spring is natural, what isn't natural is the delayed turnover in the fall due to the cooling and venting that the forest offers in comparison to bare soil or even a grass plot.
This graph demonstrate the increased thermal conduction that occurs under altered land in comparison to natural habitat. Cleared land allows for an increased in thermal conduction resulting in an increase in heat capacity. This amplifies and alters the geothermal heat gradient over time causing the warmer and more stable layer to rise closer towards the surface after many years. T
Bog and Swamp Data
There are 4 locations available for data analysis 200cm below the surface and each of these locations demonstrated a shift in 2002 and 2007. The upper graphs are the beginning of each location through 2001, the lower graph is from 2002 through March of 2017 demonstrating an acceleration in oscillations. In 2007 all 4 locations, and both upland locations, experienced a marked decline in subterranean temperatures. These oscillations validate the oscillations being recorded at the St. Paul Climate Observatory as water, and 2007 is also the same time frame when the St. Paul Climate Observatory began to demonstrate heightened levels of oscillation on their deep temperature probes. This data and time frames can be viewed here.
Junction Fen
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Big Lake Fen
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S3 Plot
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S2 Plot
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Note; The S3 plot has increased water flow moving through this region demonstrating the cooling effect of water on subterranean temperatures.
Analysis
Yearly average surface temperature during this period of time for three separate locations averaged 3.8C/38.8F, and the region closest to the Aspen and Open Upland was exactly 38.8F. This region is located deep within the forest and away from farmland and urban development. S3 Bog is much cooler due to increased water flow demonstrating the cooling effect of water. Here is the bog and fen totals.
1989 to 2017 average soil temperatures -200cm Bog and Fen:
S3 Bog 5.8C/42.4F
S2 Bog 6.3C/43.3F
Junction Fen 6.5C/43.7F
Big Lake Fen 6.6C/43.9F
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Total Average 6.3C/43.3F
Aspen Upland 6.4C/43.5F
Open Upland 7.6C/45.7F
Both St. Paul and Swan Lake demonstrated a 4F heat loss between the underground temperature and thermometer located 6' off the ground. With the natural temperatures averaging 43.4F, a 39.6F yearly surface temperature should be attained. The additional .8F loss is attributed to the massive forest and water generating a large scale overall cooling impact surrounding this small region amplifying its heat loss. This data aids in providing us with an understanding that when a region is stripped of it's forest, an immediate 2.4F rise in temperature results. As swamps and wetlands were filled in during the homesteading of our nation in the 1800's, heat vents were shut down and water diverted to the rivers increasing the heat flux below the surface. Surface water is no longer filtered through transpiration and is now reliant on evaporation resulting in increasing medical issues such as asthma and allergies. Infiltration of water into the territorial aquifers declines as the surface soils become sealed and compacted through use. The massive loss of natural vegetation decreases photosynthesis, and this naturally results in a continual yearly rise in atmospheric CO2 levels. By 1914, 44% of the lower 48 states was used for farmland alone, and logging went unrestricted until the 1930's. Any increase in forest area today is shadowed when compared to what it once was.
1989 to 2017 average soil temperatures -200cm Bog and Fen:
S3 Bog 5.8C/42.4F
S2 Bog 6.3C/43.3F
Junction Fen 6.5C/43.7F
Big Lake Fen 6.6C/43.9F
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Total Average 6.3C/43.3F
Aspen Upland 6.4C/43.5F
Open Upland 7.6C/45.7F
Both St. Paul and Swan Lake demonstrated a 4F heat loss between the underground temperature and thermometer located 6' off the ground. With the natural temperatures averaging 43.4F, a 39.6F yearly surface temperature should be attained. The additional .8F loss is attributed to the massive forest and water generating a large scale overall cooling impact surrounding this small region amplifying its heat loss. This data aids in providing us with an understanding that when a region is stripped of it's forest, an immediate 2.4F rise in temperature results. As swamps and wetlands were filled in during the homesteading of our nation in the 1800's, heat vents were shut down and water diverted to the rivers increasing the heat flux below the surface. Surface water is no longer filtered through transpiration and is now reliant on evaporation resulting in increasing medical issues such as asthma and allergies. Infiltration of water into the territorial aquifers declines as the surface soils become sealed and compacted through use. The massive loss of natural vegetation decreases photosynthesis, and this naturally results in a continual yearly rise in atmospheric CO2 levels. By 1914, 44% of the lower 48 states was used for farmland alone, and logging went unrestricted until the 1930's. Any increase in forest area today is shadowed when compared to what it once was.