We all know that boreal forests sequester an incredible amount of carbon. But a study published in the journal Science suggests something rather amazing:
It's not the accumulation of leaf litter that sequesters the most carbon, but rather tree roots and associated mycorrhizal fungi which live in and on tree roots. (These are the same amazing fungi which allow trees to communicate with each other.)
Here's the scoop from the paper's abstract:
Boreal forest soils function as a terrestrial net sink in the global carbon cycle. The prevailing dogma has focused on aboveground plant litter as a principal source of soil organic matter. Using 14C bomb-carbon modeling, we show that 50 to 70% of stored carbon in a chronosequence of boreal forested islands derives from roots and root-associated microorganisms. Fungal biomarkers indicate impaired degradation and preservation of fungal residues in late successional forests. Furthermore, 454 pyrosequencing of molecular barcodes, in conjunction with stable isotope analyses, highlights root-associated fungi as important regulators of ecosystem carbon dynamics. Our results suggest an alternative mechanism for the accumulation of organic matter in boreal forests during succession in the long-term absence of disturbance.
Researchers found that anywhere between 47% and 70% of soil carbon found in their samples was the result of fungi.
What this means for long term forest and carbon management remains to be seen, except to say we have yet another reason to better understand the amazing world of mushrooms—and to protect the ecosystems that they call home.
As the climate warms, there have been concerns that more carbon stored in leaf litter and decomposing organic matter may be released into the atmosphere due to faster decomposition rates. If this research is in fact correct, and carbon is being sequestered deeper in the soil, one might hope that it is a little less vulnerable to quick release into the atmosphere.
But that's just a layman's hope, and not something covered in this particular research. Either way, we'd better start getting serious about protecting the forests we still have, and start working on growing some more.
The fungi will thank us for it.