You could simply alter the consciousness of simulated beings to believe that the tree is complex and exists fully. This sort of dynamic pruning/altering of cons

You could simply alter the consciousness of simulated beings to believe that the tree is complex and exists fully. This sort of dynamic pruning/altering of conscious reality would dramatically cut down on what needs to be simulated. We could all be staring at placeholders (if even that) while believing we are interacting with a complex, fully defined world - in the meantime, the simulation modifies our consciousness(es) to smooth over any gaps in what could actually be a crudely defined generative world.