In our new orchard we followed the traditional advice to dig DEEP and LARGE holes.  Just as we spent MEGA BUCKS  (about $100/hole) getting these holes dug and buying Kellogg Amend by the pallet (for a 50/50 mix), I find that the latest recommendations are to dig a SHALLOW wide hole and NOT to amend the native dirt with compost.
So we have 12 giant compost amended tree holes in the orchard and about as many outside.   3 trees will be in an area that was once amended about a foot deep for a garden, but the rest of the trees outside the orchard will be in native dirt.
Here’s an OLD Dave Wilson video on fruit tree planting:

As ALWAYS, read the COMMENTS!
One person lost a tree after cutting it down to knee height as recommended in the video.
Also, the Kellogg Topper wouldn’t have been their first choice for mulch, but it’s what they had.
Interestingly, they put the mulch right up against the trunk and I’ve heard at least a thousand times not to do that as it can cause the tree to rot.  What gives?
There are numerous Dave Wilson videos at https://www.youtube.com/channel/UClShqpLDCJ-Q97zk3tsYZAw and of course thousands of related videos on YouTube.
We’re currently building “frames” around the tree holes in the orchard and we will add about a foot of our dirt / Amend mix.  When you fill deep holes, trees can settle significantly as they get larger and heavier.   We’ll probably plant the trees even higher because I wouldn’t mind keeping the raised beds around the trees. We’ll be growing all sorts of companion plants such as comfrey, lupines, yellow bird of paradise and herbs and it’ll be our summer veggie garden until the trees provide too much shade.
When we get ready to plant we’ll stick the trees in a bucket with water and some kelp and when we plant it we’ll sprinkle myccorhizae granules on the wet roots and into the planting hole where the roots will likely touch it.
If the bareroot trees have any branches, we’ll plant so that the least dense side faces south.
We amend with rock dust, gypsum, manganese, epsom salt, iron, zinc, micro minerals, humic acid, nitrogen fixing microbes and soft rock phosphate.   I was so excited when I saw that Arbico near Tucson sells 50 lbs bags of soft rock phosphate for $18.45.   I thought I’d get 10 bags as it’s so expensive to ship.  Good thing I called to see how many they have in stock, found out that it’s drop shipped from Arkansas.  So I ordered two bags and it costs $21.76 per bag to ship UPS.
It’ll be very interesting to see which planting method works better — big deep holes with 50/50 native dirt and Amend or shallow holes with native dirt.
With regards to amendments, they work when your soil is deficient of whatever it is you’re adding.
That’s why it’s best to see what your neighbors are doing and how it works for them when you plant in native soil.
We’ve paid for several soil tests and while I don’t think that the money was wasted, they’re not so helpful in our high pH calcareous soil.
In case you’re wondering why we are planting bare root trees, I’ve heard that they’ll do better than potted trees.  Everything we propagate is grown in 50% native dirt so the plants don’t have so much transplant shock.  I also really don’t care for the fertilizer granules we usually find in purchased plants no matter where we buy them.
Tomorrow I’ll pick up another load of mulberry cuttings for mulch.  We could use another 1