oak tree in gravel driveway

I'm designing the west side of my site, and I would like to plant a valley oak in what used to be a gravel driveway. It is compacted fairly well, about eight inches down. I have successfully planted hackberry trees here, but the oaks I planted next to them died. Was it the competition from the hackberries or do oaks just not do well in compacted gravel?

It may depend on the Oak and/or if it was planted from seed. Most of my Oaks are on ledge but of course they weren't transplanted.