Spruce and Peatland ResponsesUnder Changing Environments
This data set provides leaf area index (LAI) data collected across vegetation community plots within the 10 chambered treatment plots (6, 19, 11, 20, 4, 13, 8, 16, 10, 17) and 3 unchambered ambient plots (7, 14, 21) of the SPRUCE experiment project in 2017 and 2018. The vegetation community plots were established in 2014 and designated to be undisturbed and reserved for long-term sampling. LAI measurements were collected using a LICOR-LAI 2200 instrument over a standard 1x2 meter rectangular sampling frame with 50 20x20 cm grid cells. LAI was measured above the canopy and below the vegetation at the surface of the peat (living sphagnum) in the same grid cells each year.
This data set consists of images of fine-root birth, growth, and death collected using non-destructive minirhizotron technology from a warming × CO2 enrichment experiment in a forested, ombrotrophic bog. Minirhizotron images were collected ~ weekly or bi-weekly beginning in 2013 in the 12 SPRUCE experimental plots in paired hummock and hollow microtopography.
The dominant woody species in the bog, and the focus of our investigation, were trees Picea mariana (spruce) and Larix laricina (larch), and ericaceous shrubs Rhododendron groenlandicum and Chamaedaphne calyculata. In each of the 12 SPRUCE experimental plots, one pair of tubes was installed within a 1.5 m radius of spruce or larch trees (treed) and one pair was installed in areas dominated by ericaceous shrubs (non-treed), for a total of 48 tubes.
Each ~ weekly or bi-weekly imaging session resulted in ~4500 image files in JPEG (.jpg) format. To date (through the end of 2018) there are 291 sessions (including treed and non- treed sessions) and a total of ~625,000 images.
This data set consists of observations of Normalized Difference Vegetation Index (NDVI) collected via stationary sensors positioned 1.5 meter above unobstructed areas of the ground layer. Sensors were installed above undisturbed community composition plots, that are not instrumented or destructively sampled in any way, in six of the ten chambered SPRUCE experimental study plots located in the S1-Bog. Spectral data (630 and 800 nanometers) were collected at 10-minute intervals over a field of view of ~53 cm in diameter beginning May 6, 2016. Data collection ended at a different time for each sensor as batteries discharged – ranging from January 1, 2018 to April 1, 2018.
These data are provided in support of the SPRUCE publication: Small Differences in Ombrotrophy Control Regional-Scale Variation in Methane Cycling among Sphagnum-Dominated Peatlands (Zalman et al., 2018). Reports on the mechanisms controlling C cycling rates and greenhouse gas emissions using a combination of biogeochemical and microbial approaches in three low pH, Sphagnum-dominated peatlands in northern Minnesota. In particular, biogeochemical parameters (CH4 and CO2 production potentials, porewater and gas CH4 and CO2 concentrations, and associated isotopic signatures), soil chemistry (organic acids and phenolics), and microbial community characteristics (quantification of methanogen and methanotroph abundance and activity) over a 1-year period in these three peatlands. Samples were collected from June of 2013 to June of 2014.
