Repeated measures of decaying wood reveal the success and influence of fungal wood endophytes

Author: mycolabadmin
8/15/2025
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Summary

Scientists tracked how fungi and bacteria decompose fallen tree logs over five years in a Minnesota forest. They discovered that fungi living dormant inside healthy wood trees become the dominant decomposers when wood begins to decay, outcompeting fungi arriving from soil and air. Wet, ground-contact conditions and bark coverage changed which fungi dominated, but bacterial communities followed a different pattern, remaining diverse regardless of conditions.

Background

Deadwood decomposition plays a crucial role in forest carbon cycling, yet predicting decomposition rates remains challenging due to complex successional dynamics among fungal and bacterial decomposers. Fungal endophytes—saprotrophic fungi that reside latently in healthy wood until trees senesce—are rarely considered as endogenous wood traits that might influence decomposition predictions, despite their potential strategic importance.

Objective

This study aimed to track the persistence and influence of fungal wood endophytes on wood decomposition using repeated measures over five years. The research examined whether endophytes become dominant decomposers in decaying wood and how treatments affecting external colonizer accessibility (bark on/off, ground contact/aboveground) influence fungal and bacterial community succession.

Results

Fungal endophytes persisted as dominant decomposers, with 74-77% of decaying wood fungi originating from sound wood endophytes. White rot fungi predominated in both species, with treatment-specific dominance patterns where bark presence and ground contact significantly influenced fungal community composition. Bacterial communities showed convergence across treatments with increased diversity, contrasting sharply with diverging fungal communities, and no direct fungal-bacterial co-occurrence relationships were detected.

Conclusion

The findings demonstrate that saprotrophic fungi employ a strategic endophytic colonization strategy, with endophyte persistence and competitive success influenced more by treatment-driven microclimate conditions than by external colonizer arrival. Including fungal endophytes as predictable plant traits governing decomposer community assembly could improve Earth Systems modeling of carbon cycling in deadwood ecosystems.

Published in:mSystems,
Study Type:Field Experiment,
Source: PMID: 40815465