I came across this dead poplar in the middle of June of last year, colonised throughout with Polyporus squamosus. No question that the pruning wounds facilitated widespread entry of the fungus (Polyporus squamosus gains entry via exposed sapwood), which rapidly killed the poplar – judging by the amount of re-growth, likely two growing seasons following the aggressive reduction work (that’s not to say the poplar wasn’t colonised before then). Given there was another poplar immediately alongside (they would have shared a crown), I wonder whether that one suffered the same fate but some years before. Of course, other factors could have been at play here – both biotic and abiotic (I doubt the reduction work helped with energy levels!), but the presence of multiple sporophores suggests that Polyporus squamosus was at least one driver behind its death.
Now, we can see that the fungus is acting saprophytically. As with many fungal parasites this species persist beyond the host’s death and uses the locked-up resources for its own benefit and, ultimately, to the benefit of the ecosystem on the whole. The mineralisation of nutrients, and the creation of niche habitat, are very much necessary ecological processes – regardless of location.