SPRUCE S1 Bog Fine-root Production and Standing Crop Assessed With Minirhizotrons in the Southern and Northern Ends of the S1 Bog

Fine roots contribute to ecosystem carbon, water, and nutrient fluxes through resource acquisition, respiration, exudation, and turnover, but are understudied in peatlands. This data set reports fine-root peak growth and standing crop measurements from a forested, ombrotrophic bog as determined using non-destructive minirhizotron technology. Minirhizotron images were collected throughout the growing seasons of 2011 and 2012 at the southern and northern ends of the S1 bog across gradients of tree density in paired hummock and hollow microtopography. The dominant woody species in the bog, and focus of the investigation, were trees Picea mariana and Larix laricina, and ericaceous shrubs Rhododendron groenlandicum and Chamaedaphne calyculata. The data were derived from minirhizotron images where root length and diameter were measured on ~weekly images and used to calculate: (1) Annual fine-root production and peak standing crop in 2011 and 2012; (2) Seasonal fine-root phenology throughout the growing seasons of 2011 and 2012; and (3) The distribution of newly-produced fine-root length throughout the peat profile in 2011 and 2012. The measurements were made in the S1 Bog, a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). These minirhizotron images were collected prior to the construction of the SPRUCE experimental plots.