I live in a high fire area, the recommendation here is to keep organic mulch to 3 inches (7-8 centimeters) thick or less. I find once the soil is active, it is hard to keep more than a thin layer of mulch due to rapid decomposition. Anything too thick for mulch should be buried or burned (in a fireplace) with ashes returned to the soil (e g. tree branches). No exposed compost piles! (Look up trench composting for something that is ok).
compost
thepoliticalcat