Evaluation of Two Techniques for Quantification of Hyphal Biomass

Currently, oak woodlands of Northern California and their associated mycorrhizal fungi are receiving more attention. In order to address the impact mycorrhizal fungal associations have on survival of various tree species in oak woodlands, we investigated the extramatrical fungal hyphae associated with several mature oak woodland tree species. Specifically our objective was to quantify the fungal hyphal biomass in soils near blue oak (Quercus douglasii), interior live oak (Quercus wislizeni), foothill pine (Pinus sabiniana), and Ponderosa pine (Pinus ponderosa). We developed methods to determine hyphal length using microscope images with either WinRHIZO Pro 2002© software or the more common gridline intersect method (GIM), which calculates hyphal length using Newman’s original (1966) and modified equations (Tennant 1975). After comparing methods, we found that using microscope images in addition to Tennant’s equation resulted in the most accurate and efficient way of estimating hyphal biomass. Information gathered will be used to determine whether hyphal length is correlated with survival and growth of oaks in California’s oak woodlands.