Compost them first.
So just spreading them out doesn't really work?
No, they become a mat that nothing grows through. You could run them through a shredder, that might help.
Good point.
They break down faster if mixed with soil and manure and kept moist, turned over every so often. You end up with a nutrient rich humus that helps to build up soils.
Ahh that's the rich coffee looking soil. On my father's property I'll find all the soil we need for plantings over by a intermittent stream he has. That soil is so rich. It's filled with tons of leaf fall and dead plant matter. I'd imagine some bugs as well.