UTARB CO2 efflux

CO2 efflux from forest soils (RBG) is a prominent flux in the global carbon cycle. RBG is derived from root (Rroot) and microbial respiration, which is highly dynamic and depends on edaphic and environmental conditions, as well as root functional traits and microbial community composition. It is unclear how root functional traits affect rates root and microbial respiration rates; however, incorporating them may help parse out how the relative contributions of root and microbial respiration affect RBG. In-situ root trays housing entire root systems of 3-4 functional root orders and their surrounding soil were installed in a paired experimental design on eight temperate tree species that varied in their root functional strategies and mycorrhizal affinity. RBG was measured bi-weekly to monthly for nearly one year using a custom chamber attached to a gas exchange system, with concurrent measurements of soil moisture and temperature. We discuss how incorporating root functional traits as modulators of the autotrophic contribution to RBG could be considered when modeling total soil CO2 efflux from forests.