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Information on the interactive Roaring Fork Observation network can be found at:

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If a Tree Falls in the Forest...

By Adam Korenblat

(A special post from our summer intern)

North Star Preserve is a 175-acre tract of open space located east of Aspen along the Roaring Fork River. This area supports high levels of biodiversity among bird species and hosts a diversity of habitats, including aspen groves, riparian areas, wetlands, and meadows. Due to this site's ecological significance, Pitkin County is interested in tracking soil moisture conditions and has partnered with AGCI to monitor North Star preserve starting in 2015. This May several individual sensors at one of the North Star sites stopped recording information on the associated web link  AGCI uses to receive data.

Just a few days after the sensors went silent, we set out to find what had tampered with one of the North Star sites, specifically, the North Star Aspen Grove site. There are currently two sites located on the North Star Preserve, one located within the aspen grove and one located near the aspen grove, in a transition zone between a fen and a meadow. Because the sites are located far from any buildings, checking the sites during any mishap requires an in-person visit. Elise, AGCI’s research associate, and I prepared ourselves for various outcomes. In the area where the station is located, multiple sources of disturbances to the station are always possible.  Signs of bears, moose, and elk are all common in the area. Alternatively, there are many small mammals that could have chewed through the wires and caused the iRON equipment to stop collecting data. We armed ourselves with bear spray and reflective tape to fend small mammals off any exposed wires and brought along a toolbox with the full suite of equipment necessary to fix a toppled tower. We ventured into the aspen grove to assess the damage done to the site.

We arrived at the site to find no evidence of bear, moose, elk, or small mammal damage but instead a large, dead and highly weathered aspen tree. The tree had fallen merely 2 feet from the iRON tower and managed to land directly on one of the three guy wire stakes attached to the station. The force of the resulting jerk to the tower cleanly broke the temperature/relative humidity sensor's cable and managed to unplug the temperature sensor and 8 and 20 inch soil moisture probes. What we believed to be a severely damaged site turned out to be a relatively easy fix. We replaced the broken temperature/relative humidity probe and re-plugged the temperature, 8 inch soil moisture, and 20 inch soil moisture probes. The hardest part of the fix was removing the guy wire and stake from under the dead aspen tree.

The fallen tree near the Aspen Grove site left us feeling very lucky, considering that the tree could have easily taken out the entire station. We prepared for a disaster and came upon a minimally damaged station. This day gave us a reminder that coming prepared allows for a smooth running day. Even though bringing a full toolbox may seem like a burden, we were able to make the necessary repairs and, despite the negatives involved with a damaged site, we came out with positive attitudes.

About the Author:

Adam Korenblat is currently a student at the University of Colorado at Boulder. He joined AGCI as an intern this summer and moved out of his apartment in Boulder to head up to the Roaring Fork Valley. After a first day that consisted of collecting soil at Spring Valley, the iRON’s newest site, he immediately came to the understanding that this internship fits him quite well. Overall he is enjoying this internship very much and looks forward to many more days in the field!

Rain, Snow, and the Soil Moisture Situation

While Aspen and the high country enjoyed a dusting of snow over the weekend, lower elevations in Basalt, Carbondale, and Glenwood Springs instead just felt a deluge of cold rain. In an arid state like Colorado, any type of precipitation usually seems like a good thing, but whether that precipitation comes in the form of rain or snow can make a difference to ecosystem conditions that lasts throughout the growing season.

Each spring since the iRON stations have been installed, they show sudden peak in soil moisture as snow cover melts and as the ground thaws out. Depending on the elevation of the individual station and the snowpack and temperatures we have had over the winter, these spikes in soil moisture usually occur somewhere between mid-March and mid-April. Once this "spring soak" has occurred, soil moisture at the iRON sites tend to follow a general trend decline, with only small spikes in moisture increase, until mid to late summer, when heavy intensity rain storms of over 0.8inches of rain in a single day help to recharge soil moisture all the way down to a 20 inch depth.  The graph below shows an example of the patterns of soil moisture shown at the Sky Mountain station from its installation through the present.

Other, lower elevation stations, such as the one at Glenwood Springs may show an earlier date of soil saturation. This is the first winter/spring transition for which there has been a station at Glenwood Springs, so we are unable to compare it to other years, but an increase in soil moisture at all three depths (2,8, and 20in) had already began around February 14th this year, which a sharper spike in soil moisture increase on February 18th. As our data record grows will be able to compare dates of soil thaw, periods of warm winter temperatures, and rain events to soil moisture in order to better understand the interplay between these factors.