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Harvard Forest REU Symposium Abstract 2014

• Title: The Effect of Tree Species on Soil Carbon Content and Variability
• Author: Marisa E Houlahan (Harvard College (Harvard University))
• Abstract:

  As atmospheric CO2 levels continue to rise, research has increasingly focused on the ecosystemic impact and allocation of surplus carbon. Though forest soil organic matter (SOM) stores more carbon than any other terrestrial source and contains roughly twice as much carbon as the atmosphere, relatively little is understood about belowground carbon cycling or its relationship to forest composition. New England forests in particular have been identified as potential carbon reservoirs, so it is crucial to understand soil carbon and tree species interactions in the context of New England’s land use history and species composition. In this study, we sampled the organic layer across a mixed deciduous forest in Massachusetts using a cordless drill and steel coring cylinder. For each of 214 soil cores, we recorded data on leaf litter and canopy species composition as well as tree species associated with the core. We dried, sieved, root picked, ground, and ashed each core to determine SOM content and further analyzed 33 cores to determine carbon and nitrogen content. Across coring sites we found a significant correlation (p < 2.2 x 10-16) between percent SOM and percent carbon content, where approximately 52% of SOM is made up of carbon. We expect to find that sites dominated by conifers will have lower percent carbon than sites dominated by hardwoods. This study provides a snapshot of New England soil carbon content and variability, and we plan to repeat this experiment in 3 to 4 years to examine how soil carbon storage changes over time.

• Research Category: Soil Carbon and Nitrogen Dynamics