Gary, have you ever posted this for discussion in it's own thread? Its very interesting.
I have questions for them!
I'm wondering about the 10cm depth thing. Specifically, will the beneficial effects still transpire without the burying of the material? Because I'd be using it exclusively as mulch.
And then, whether non-deciduous, non-hardwood, non-conifers will still work. Namely, the juniper ash that is the de facto mulching material around here. It is in no way a traditional hardwood. However, it is decidedly slow to decompose. I don't know if that's good, bad, or otherwise.
Either way, I'm going to look for hardwood mulch when its time to give the plants some protection next month.