I get chips dumped on my lot all the time. One year I got so much dumped it took me over a year to move them all, ran out of cardboard to cover the grass. The only difference I saw was a color change. The center was very hot and in the cooler mornings you can see the steam. It had the white threads but it was more noticable in the center. They break down a lot faster on top of the soil than in a pile of pure chips.We bought a 2000L bag of woodchip for our garden (approx 1m x 1m x 2m). Plans changed and it ended up sitting on the end of our drive in full sun for 1 year. It didn't appear to break down in the slightest and there's no sign of fungal growth (so no white threads). It's now spread on the beds and looks like it'll be a long time before it breaks down. This was hardwood chips.
MOD