I have a 50' Colorado Blue Spruce in an area where I am going to lay new sod. The skirt is barely above ground level. I am not sure whether to sod beneath it right up to the trunk, or how far in from the canopy edge the sod should end.
It would be best if you didn't install any sod in the drip line of the tree. The new sod will take up water from the tree and block gas exchange. That would be the best case scenario for the tree. You could install sod a little more than halfway between the drip line and the trunk and the tree will survive.
