Vertical stratification of the foliar fungal community in the world's tallest trees.

PREMISE OF THE STUDY: The aboveground tissues of plants host numerous, ecologically important fungi, yet patterns in the spatial distribution of these fungi remain little known. Forest canopies in particular are vast reservoirs of fungal diversity, but intracrown variation in fungal communities has rarely been explored. Knowledge of how fungi are distributed throughout tree crowns will contribute to our understanding of interactions between fungi and their host trees and is a first step toward investigating drivers of community assembly for plant-associated fungi. Here we describe spatial patterns in fungal diversity within crowns of the world's tallest trees, coast redwoods (Sequoia sempervirens).

METHODS: We took a culture-independent approach, using the Illumina MiSeq platform, to characterize the fungal assemblage at multiple heights within the crown across the geographical range of the coast redwood.

KEY RESULTS: Within each tree surveyed, we uncovered evidence for vertical stratification in the fungal community; different portions of the tree crown harbored different assemblages of fungi. We also report between-tree variation in the fungal community within redwoods.

CONCLUSIONS: Our results suggest the potential for vertical stratification of fungal communities in the crowns of other tall tree species and should prompt future study of the factors giving rise to this stratification.