Ten permanent snowcourses under various cover types were established
beginning during 1962. Each snowcourse has 10 sample points on each
course. Each sample point is marked with a post from which a weighing
scale is hung for measurement of SWE. Watershed S1 has an upland
course in an aspen (Populus tremuloidse, P. balsamea, and P. deltoids)
stand. Watershed S2 has 2 upland courses in aspen stands, and a bog
course in a black spruce (Picea mariana) stand. Watershed S3 has an
upland course in a red pine (Pinus resinosa) stand. Watershed S5 has 2
upland courses in aspen stands, an upland course in the open and a bog
course in a black spruce stand. The final snow course is in an open
fen called Junction Fen. The four southern points along the S1 uplands
snowcourse were moved several meters during 2010 to accommodate new
roads.
Though hardwood forest stands near snow course transects have not been
managed, forest cover is shifting from overstory dominance of aspen
and birch (Betula papyrifera) to balsam fir (Abies balsamea), red
maple (Acer rubrum), basswood (Tilia americana) and red oak (Quercus
rubrum). The red pine in the S3 watershed was planted during 1963
following clearcutting of the previous stand.
The S2 and S5 bogs are ombrotrophic peatlands with mature black spruce
(Picea mariana), tamarack (Larix laricina), ericaceous shrubs
(Rhodendrom greonlandicum, Chamaedaphne calyculata, Vaccinium
angustifolium), and Sphagnum mosses. Junction fen is a poor fen with
no trees except along the margins. The surface cover is dominated by
ericaceous shrubs (Chamaedaphne calyculata), Sphagnum mosses, and
Polytrichum mosses. All the peatlands have hummock and hollow
microtopography. Each year, the first measurement was made in mid to
late February at the typical time of maximum depth of snow pack.
Measurements were repeated every 2 weeks until no snow cover remained.
Snow cores were collected a predetermined distance and direction from
the permanent posts to eliminate bias in sample location and repeated
sampling of the same area over time. The tubes were waxed inside and
out with automobile wax to reduce adhesion of snow to tube walls and
facilitate emptying between snow cores. A Mount Rose (Federal) Snow
Tube was used for depth measurements and SWE determination. The snow
tube is a hollow 3.8 cm (1½ inch, inside diameter) aluminum tube. The
tube has a sharpened serrated edge at the bottom and the outside is
marked off in inches. The tube is 78.7 cm (31 inches) long. While
rarely needed, extensions of 31 inches each can be added. The empty
tube is weighed before sampling. If the snow was soft or fluffy, the
tube was inserted through the snow to the ground surface. If the snow
was compacted or crusted, the tube was turned or screwed through part
or all the snow to the ground surface. With the tube resting on the
ground surface the snow depth along the outside of the tube was read
from graduations on the exterior of the tube to the nearest 1.3 cm
(0.5 inch). The tube was then turned to cut into the litter layer to
reduce the possibility of snow from falling out the end when the tube
was lifted. When the tube was out of the snow, the litter was
carefully removed from the end. The length of the snow core inside was
observed through slots along the length of the tube and compared to
the depth reading (data resolution 2.5 cm/1.0 inch). If none of the
snow had fallen out the bottom, the tube and core were weighed using a
hanging weigh scale (Chatillon milk scale 6lb capacity). The
difference in weight between the empty and full tube was converted
into inches of water (1 ounce = one inch of water; data resolution
0.25 cm/0.1 inch).
From 1962 to February, 2012, frost measurements were made with a Lake
States frost penetrometer (Stoeckeler and Thames 1958), which is a 1.3
cm stainless steel rod about 1 m long with a sharpened and slightly
flared point. The bottom 45 cm were marked in 2.5 cm intervals. The
attached driver, a 5.5 kg weight, was lifted 45 cm and dropped,
whereupon the weight strikes a plate that drove the penetrometer into
the soil. Additional manual force was applied as necessary. When the
flared point broke through the frost movement was perceptibly faster
and easier than in the frost layer. The frost depth was estimated to
the nearest 2.5 cm by subtracting the number of increments remaining
aboveground from the total number of increments. On the rare occasion
when frost was deeper than 45 cm, it was recorded as 45 cm. If the
frost penetrometer hit a buried object in the peat, like a log, it was
pulled up and moved to another location. A bouncing sensation with no
downward progress of the probe was characteristic of impacting a
buried log in peat. After Feb 16, 2012, frost depth was measured using
a 1.0 cm (3/8 inch) or 1.3 cm (0.5 inch) masonry with a 91.4 cm (36
inch) shank driven by a portable drill. Frost depth was measured as
the distance until resistance to drilling decreased at the interface
of frozen and underlying unfrozen substrate. The depth was marked
along the drill bit, the drill was retracted from the hole, and the
depth was measured with a tape measure to the nearest 2.5 cm (1 inch).
More information on study sites and methods can be found in:
Sebestyen, S.D., C. Dorrance, D.M. Olson, E.S. Verry, R.K. Kolka, A.E.
Elling, and R. Kyllander (2011). Chapter 2: Long-Term Monitoring Sites
and Trends at the Marcell Experimental Forest. In Randall K. Kolka,
Stephen D. Sebestyen, Elon S. Verry, and Kenneth N. Brooks (Ed.).
Peatland Biogeochemistry and Watershed Hydrology at the Marcell
Experimental Forest (pp 15-71). CRC Press, Boca Raton, FL.
Citations:
Church, J. E., Jr. (1917), Snow surveying: its problems and their
present phases with reference to Mount Rose, Nevada and vicinity, in
Proceedings of the second Pan American scientific congress,
Washington, U. S. A., Monday, December 27, 1915 to Saturday, January
8, 1916., edited by Woodward, R. S., pp. 496-560, US Government
Printing Office, Washington, DC.
Clyde GD. 1931. A new spring balance for measuring water content of
snow. Science 73: 189−190.
