Pacifica (autumnwinds) wrote,
Pacifica
autumnwinds

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The Nitty-Gritty

I thought it might be prudent to actually explain a little of what goes on at each plot we sample, so you folk know what it is we’re doing. There’s three major tasks going on: trees, vegetation, and fuels.

Trees (2 people): Our plots have a radius of 37.2 feet. We count every tree that falls within that plot, then take the diameter at breast-height (4.5 feet), the height (with a clinometer, a sort of floating handheld protractor), the percent of live canopy down the trunk, the height from the ground to live canopy, its species, status (live, dead, broken, forked, mistletoe), and stage in the stand (dominant, codominant, suppressed, intermediate). We also use a cruise angle to identify any large significant trees that are outside the plot, and measure them the same way. When all measurements are complete, we take core samples with a hand-driven borer. 2 samples of each size class (0-6 in, 6-12 in, 12+in), of each species. These cores are labeled and stored for later analysis with a mass spectrometer in the UI labs, so we can estimate age. The other measurements will be used for correlations between age and height.

Vegetation (1 person): We lay a 75 ft line from plot center parallel to the contour of the land (not up or downhill). Five random numbers are chosen between 1 and 75, and 25ft transects lying perpendicular to the original 75 ft tape are laid out at these foot markers. Then, in 5-foot intervals starting at a random number between 1 and 10, we evaluate the vegetation in quadrats 1m square along the transects, 5 per transect for 25 quadrats total. In each quadrat we identify every species of plant (recording the four-letter code formed from the first two letters of the genus and species name…Yarrow, Achillea millefolium, is ACMI), and estimate the percent coverage and average height of the plants. Yes, we’re using both metric and imperial units. It pains me.

Fuels (1 person): Starting at the plot’s NW corner (I know circles don’t have corners), a 75 ft tape is laid out due East. The recorder walks along the transect, recording the number of intersecting sticks in the 1 hr (<1/4 in), 10 hr (>1/4 in, <1 in), and 100 hr (>1 in, <3 in) size class for the first 10 feet. From 10 feet to 20 feet, only the 10 and 100 hr fuels are recorded. Any wood with a diameter greater than 3 inches (branches, logs) is recorded, numbered, measured, and designated with a specific stage of decay (1 is still green, 5’s can be kicked to bits). Then a South, West, and North transect is done, to form a square around the plot. At each corner, we measure vegetation coverage, litter and duff depth, litter percentage, and slope.

Those are the major tasks. We also fill out an extensive plot description form (ground coverage, tree coverage, slope, aspect), get the latitude and longitudinal UTM coordinates and the elevation with the GPS, take digital photos from the NW and SE corners, and mark the plot with a metal tab (and record plot center distance and azimuth from that point.

Busy busy.
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