Hugelkultur materials, digging?

Hi,

I am thinking of building a hugel on some public land as a neighbourhood project, on top of a lawn

The materials I have:
tree trunks and branches mainly beech and other deciduous wood (oak, ash, maple)
municipal compost (I have used this in my garden with success)
if necessary, horse manure

My question:
Can I build a hugel with just the top two ingredients?
Do I need to cut up the sod and place it over the top of the hugel?

Reason I'm asking, I could do a large scale hugel with the same material somewhere else, and not needing to dig would make it feasible.

Another question, after how many years can I expect the wood to be rotted away enough that the hugel could be flattened if the land is used for building? We have annual rainfall of about 1300mm and temps between -10 and 30 Celsius

The sod will break down with other materials on top.

Your other question about the time it woud take to break down would depend on the wood you are using.

You can definitely build right on top of grass/dirt without digging. The thicker or bigger it is, the better and faster it will break down. Big logs(1-3 feet/up to 1m diameter) will take 10-20 years to decompose, small logs (2-12"/50-100mm) can be rotted in just a year with enough moisture and soil life. If you need to work the land later, just yank the big 1/2 rotted logs out and remove all the wonderful soil to use somewhere else.