The benefits of mycorrhizae to plants in nature are not known. One presumed benefit of mycorrhizae is increae phosphorus uptake, but evidence for this is based mainly on greenhouse pot experiments. Newly developed techniques and an experimental rhizotron now make it possible to quantify the phosphorus made available to mature trees in nature by ectomycorrhizae. In addition, new observations and recording techniques using the Soil Biotron at the University of Michigan Biological Station make it possible to quantify effects of fungivory on phosphorus uptake by mycorrhizae. This research will determine (1) if trees and fungi use phosphorus stored in the ectomycorrhizal sheath asynchronously, (2) seasonal patterns of grazing by microarthropods on mycorrhizal fungi, and (3) seasonal patterns of phosphorus availability in the rhizosphere. Field observations will be conducted on white pine trees (Pinus strobus) and the common fungus, Cenococcum geophilum, in a mixed deciduous forest in northern Michigan. %%% Much previous research along these lines has been restricted to container experiments in greenhouses. This research will provide the first detailed study of phosphorus availability, phosphorus use, and grazing effects on mycorrhizal associations in a field situation.
