I have just learned about hugelkultur and can't seem to find out whether or not spruce trees are good to use for these types of raised beds. It's nearly the only type of tree that grows in my area. Thanks!
In order to break down the spruce logs you're going to want to throw some mushrooms you found under spruce trees (like Phoenix Oysters, or Wine Caps) in it to decompose it quicker, because it could take a long time to start decomposing it due to the lack of proper decomposes available.
You may also want to try to attract ants with sugar, because the wood would be a great food source for them.