The Conifer Coral, Hercium abeitis, grows on pines and would be a good candidate for inoculating pine stumps.
I have seen this mushroom growing from partially submerged logs. The fact that it enjoys this habitiat leads me to believe it would be happy growing from stumps. Literature from places that sell plug spawn for this mushroom (Fungi Perfecti) support the theory.
The Conifer Coral is from the Hericium family and is related to the Lions Mane which is a beatutiful mushroom also. They are both choice edibles and are easy to prepare.
I am going to spread this mushroom around to some pine stumps this year. There are plenty to inoculate with the pine beetle kill. I encourage you to do the same.
I can not walk by a stump without thinking, that stump could be growing mushrooms. Stumps are the most under utilized substrate (material) for growing mushrooms that I see. Choosing the right mushroom for the stump is important, but many mushrooms will grow on a variety of stumps. Cottonwood stumps in particular will host a wide variety of mushrooms. The mushroom consumes the stump and the root system, and mushrooms can be harvested for years on a seasonal basis. The root system gives a place for the mycelium to hide in bad weather, and a place to get moisture for fruiting when the weather is ripe for the flush.
It bothers me to see stumps ground up, pulled out of the ground, or chemically removed, when they could be inoculated. Food can be harvested for years, and the stump is reduced to great soil for planting. When included with inoculation of the tree material removed, food can be harvested from a process that usually involves a lot of waste, and filling of our landfills.
Good candidates are oysters for hardwoods, and conifer corals for conifers. Inoculation can be with dowels or various spawns. This is another great way that mushrooms can help reduce waste while providing a usable product.