Interactive Effects of Climate Change and Fungal Communities on the Decomposition of Wood-derived Carbon in Forest Soils

I would like to thank my advisors, Drs. Sigrid Resh and Evan Kane, for their continued guidance and support in all things academic and research related during my Master of Science program. Thank you for believing in me and choosing me to work on this project. If it weren't for their collaboration, this project would never have happened. Thank you all for the input and advice revolving around soils, forest ecology, and fungi. Thank you to Dr. Chad Deering for serving on my committee. Thank you to Jennifer Eikenberry for analyzing many of my samples and for constantly helping me to learn and grow as a scientist in the laboratory setting. I would also like to thank Joe Plowe for helping to set up this project during all stages of preparation. Thank you to Jim McLaughlin for preforming FTIR analysis on my wood samples. data collection could not have been completed as efficiently without your help. The company was greatly appreciated as well. Lastly, I would like to acknowledge everyone who worked on the Aspen-FACE project. Abstract Soils are the largest sinks of carbon in terrestrial ecosystems. Soil organic carbon is important for ecosystem balance as it supplies plants with nutrients, maintains soil structure, and helps control the exchange of CO2 with the atmosphere. The processes in which wood carbon is stabilized and destabilized in forest soils is still not understood completely. This study attempts to measure early wood decomposition by different fungal communities (inoculation with pure colonies of brown or white rot, or the original microbial community) under various interacting treatments: wood quality (wood from +CO2, +CO2+O3, or ambient atmosphere Aspen-FACE treatments from Rhinelander, WI), temperature (ambient or warmed), soil texture (loamy or sandy textured soil), and wood location (plot surface or buried 15cm below surface). Control plots with no wood chips added were also monitored throughout the study. By using isotopically-labelled wood chips from the Aspen-FACE experiment, we are able to track wood-derived carbon losses as soil CO2 efflux and as leached dissolved organic carbon (DOC). We analyzed soil water for chemical characteristics such as, total phenolics, SUVA254, humification, and molecular size. Wood chip samples were also analyzed for their proportion of lignin:carbohydrates using FTIR analysis at three time intervals throughout 12 months of decomposition. After two years of measurements, the average total soil CO2 efflux rates were significantly different depending on wood location, temperature, and wood quality. …