Elevated tropospheric CO2 and O3 may not alter initial wood decomposition rate or wood-decaying fungal community composition of Northern Hardwoods

Abstract

We examined the effects of elevated CO2 and/or O3 on the wood-decaying basidiomycete fungal community and wood decomposition rates at the Aspen Free-Air CO2 and O3 Enrichment (Aspen FACE) project. Mass loss rates were determined after one year of log decomposition on the soil surface, and wood-decaying basidiomycetes were isolated from decaying wood and identified via DNA sequencing. Aspen (Populus tremuloides Michx.) and birch (Betula papyrifera Marshall) wood differed significantly in wood-decaying basidiomycete fungal communities and decomposition rate. Twelve years of site exposure to elevated CO2 and/or O3 did not have significant effects on wood-decaying fungal communities. Growth under elevated CO2 and/or O3 did not produce wood that differed in decay rate from that grown under ambient atmospheric conditions. Similarly, wood decay rate was not altered significantly when decomposition occurred in elevated CO2 and/or O3 environments. Our results suggest that wood-decaying fungal community composition and decomposition rates of northern hardwoods may not be directly affected by elevated tropospheric CO2 and O3.