[roenxi]

Mmm. Maybe. There is a plausible theory [0] that our coal deposits came from the era between when plants learned to produce lignin but bacteria didn't know how to break it down.

Given that lignin eating bacteria are now quite common, it is unlikely coal seams will form of the same quantity and quality.

[0] https://en.wikipedia.org/wiki/Coal#Formation

[s1artibartfast]

I Think there is some confusion between coal formation rate and coal formation volume. My understanding is that more coal has been formed since the cretaceous than during the cretaceous.

Figure 1 in the link below provides a good demonstration of north american coal formation over time.

https://www.pnas.org/content/113/9/2442

[DFHippie]

I believe it's fungus that breaks down the lignin.