Perhaps I am alone in this but it seems that when I plant a tree, unless its bare root, I always have a dearth of earth! It magically disappears even though I'm adding outside volume to the void!
I decided to approach the problem as scientifically as an electrician and hobby gardener can. So the next tree I took a sapling planter bag and put the shovels I removed from the newly forming hole and dumped them into the bag.
The result was incredible! I now magically had too much soil!
In keeping with the return of surplus and maximum yield i have started to do this with all large plantings and i merely dump the excess yield into the nearest raised bed and use it to level the settling soils in my beds and also to top off the area surrounding the tree should it settle!
I highly suggest a mary Poppins style soil sack the next time you plant anything that requires removing soil rather than just spading in it!
Hopefully this is a helpful tip for the new planters like myself!
Just before planting the latest trees, I had read the "How to Plant Trees" chapter in Peter Bane's Permaculture Handbook. He suggests throwing down some cardboard to catch the soil from the tree-hole so it doesn't all disappear into the grass. This works well, and makes it easy to tip the cardboard at the end to pour the rest of the crumbs where you need them.
Willie Smits: Village Based Permaculture Approaches in Indonesia (video)