Country: United States
Site: Dot Lake CALM-Code: U58
Timezone: UTC/GMT -09:00 hours
Vegetation Type: Deciduous Forest
Responsible Person: Leah M. Mackey
Transect Length: 100
Offset: 5 m
DESCRIPTION OF AREA CONTAINING SITE:
Dot Lake is an extremely small community along the Alaska Highway. The ALN site is located between milepost 1365-1364, approximately 5 miles north of Dot Lake Village. As you head south on the Alaska Hwy the site is just past the state sign posting “Tok Jct. 50mi, Tetlin Jct. 62mi”. Pull over on the South side of the road about 200 yds past the sign. Walk south into the trees about 200 yards. At second major game trail look for post 21 and the air sensor on a spruce tree. Trail runs east to west. The area vegetation is sparsely to heavily forested, with small clearings and trails. Black spruce dominates the landscape, as well as other shrubs, trees, moss and lichen cover.
The site was established in 2010 as a demo/test site for a different style of installation – as opposed to the 50x50m grid. The site was installed as a continuous line following a game trail. The mid-point of the line is found at N63.67475 W144.14597 and contains continuous soil temperature & soil moisture sensors at ‘above permafrost’ & ‘just below surface’ levels. An air temperature sensor is installed on a spruce tree near stake 21. All sensors collect and store data on a 30-minute continuous cycle. Each stake and/or measurement was made about 1 meter south of the trail. The goal of the site it to include more forested sites into the overall project coverage. Open areas tend to be favored for site selection due to accessibility and ease of installation. As an observation, it seems that open areas are more prone to thaw than those with canopy cover. The grid was established in 2010 in the second year of a cooperative agreement with the Yukon River Inter-Tribal Watershed Council and the U.S. Geological Survey.
SAMPLING DESIGN AND METHOD:
The Dot Lake site was chosen to increase the range of distribution of Active Layer Network sites that are predominately forest.
The site consist of a single 500 meter line with stakes every 10 meters and measurements made every 5 meters, for a total of 100 data points. A game trail was followed and orange flags placed at trail diversions to mark the location. Measurements were taken about 1 meter off (south) of the trail every 5 meters. The measurements were taken at the lowest surface level within about 0.3m of the designated point, to minimize the questionable influence of tussocks on the AL measurement. The "surface level" was determined to be the top of the low-lying vegetation (i.e. moss, lichen, low-bush berries). Thaw measurements greater than 1.3m were noted, but not used in calculations, as of 2009.
[CALM protocol suggests a grid size of 100mx100m, due to the slight modification of the site setup, we consider this site a test site and should not be said to follow CALM protocols.]
The soil climate station was established in early September 2010 and is located near grid center. The station monitors air temperature, soil temperature & soil moisture.
HOBO micro station was installed at the grid center. A ~30cm4 hole was dug down to the permafrost layer at 48cm. One set of soil moisture and soil temperature sensors were placed just above the permafrost layer and one set just below surface level. Soil samples were cut from 48cm and 25cm (cubes) to be analyzed for soil moisture content.
HOBO pro v2 temp/ext temp sensor was installed, recording air temperature, near the grid center about one meter off the ground surface. The Hobo data logger is set to store data on 30min intervals for up to 428 days.