Wow a
cubic metre?

I hotwire the rocker / deck shape and then cut the outline
Throw away big pieces.
Deck shaping is again a rough cut first then surform shaping.
I get about 3/4 of a shopping bag of (mostly) rough dust like beads mixed with some fine dust.... lets say 10L max from a board. I don't feel bad about that going to the tip.
I guess if you feel bad you could put it in a left over paint thinners can with some solvent and you will get it all to melt down to bugger-all. Then take it to the chemical shed at the tip and disclose the contents to them. I take my leftover thinners tainted with 2K to the chem shed and they don't charge.