The leaves and stuff in my backyard just aren't decaying. They dry out, turn black, then winter comes and freezes the ground for 5 months. When spring rolls around again, everything is practically mummified. There has been a perfectly intact, unchanging, piece of banana peel sitting on the ground for 3 years! And no, I couldn't find any worms. Is it all the pine needles causing this? Why and how does this happen??