So - next year I'm going to be clearing and putting in a garden area. My garden area has 9 fir trees that will need to come down. Instead of bulldozing it or doing the stump grinding thing, I was thinking about cutting the trees off 4 feet off the ground, and then inoculating them with Phoenix Oyster spawn.

My theory is that the stumps won't do too much blocking of sunlight, and they will eventually decay but hopefully I'll get some shrooms out of the process. Has anyone intentionally cut a tree to inoculate the stump?

The garden beds will basically just be piles of branches covered with mounds of topsoil from our house excavation, so sorta-hugels. I was just thinking today that wouldn't it be wonderful if the mycelium just travelled across the whole entire area and I got mushrooms out of the hugels as well? Not sure if that would work, but I do know how mycelium is beneficial in a garden so I'm hoping that will work out to be a good system.

Yes, some people intentionally try to get mushrooms out of stumps. Phoenix oyster sounds like it should work. Some mushrooms grow mostly on stumps. You will need to drill more dowels for a stump, and they make take an extra year to fruit, but stumps often fruit for many years in a row.
John S
PDX OR

If these are quite large trees that you're having professionally cut, let the logger decide how big stumps should be, for safety reasons. Taller stumps tend to be drier. A short stump will retain moisture better. You could have them cut a dish shaped hole in the center of the top and fill it with water occasionally.

Inoculation should be done immediately after the trees are cut. Wild spores are everywhere. Wax the entire cut after. This will block spore entry and help retain moisture.

Great ideas, Dale. The only disagreement I would have is that I would inoculate two weeks afterwards, because living trees naturally have anti-fungal chemicals in them to stop fungus from attacking the tree. After two weeks, they are mostly all gone.
John S
PDX OR

These are not huge trees, I'll be cutting them down myself... so I'm thinking if I wax the cuts after I cut them, and then wait a few weeks before inoculating, would that work to make sure I don't get wild spores?

waxing can help. Sounds like a good plan. You can't ensure that you won't get any weed fungi spores. Surely you will get some. The best strategy is to try to plan it so your preferred species will dominate the stump.
John S