Auger used to plant trees
Professionally speaking, I am a long-term member of a Forestry Dept. that has been very progressive in terms of following and adapting modern, research-based methodology. As such, we long ago abandoned the use of powered augers in preparing holes for tree planting. It never was a big part of our program anyway, but when we learned of the pitfalls-pun intended-of using this type of equipt. in our clay-based soils, all use stopped. Those problems are: In clay, the sides of the hole can become "glazed" such that, upon drying out later, they can act like a brick wall inhibiting roots from advancing beyond the small area of loose soil that had been backfilled. They also tend to create holes that are far too deep. Sure, material can be placed back into the hole and then stomped down, but it's hard to know you've actually compacted it enough to prevent later settling. And additionally, the holes so produced are very vertical. There is no "breakout zone" whatsoever in an auger-dug hole.
We have at our disposal a stump grinder and for decades, we've used this machine to prepare perfect, shallow, and tapered planting "beds" in our street and park planting programs.
Another part of my job wherein most of my efforts are directed these days is in our Stormwater utility. Most of the planting work that gets done here is not in-house. Native landscaping contractors are usually the ones on hand to do this tree planting. And every one of them wants to use an auger to plant. I'm having a hard time dealing with this because in their world, this is just what you do, whereas in my world, augers play no role in tree planting.
So I'll throw it out here: Those of you in more of a professional capacity-what do you think about augers/tree planting? I will concede at the outset that in very sandy ground, it probably does no harm to use these things. But where we're located, it's clay loam with heavy red clay subsoil in most instances. This past year's drought notwithstanding, soils are usually moist.
I've written specs to try to achieve a compromise, mentioning that the top of the hole be manually tapered outwards, that the holes not be dug half way to China, and that if wet, the sides be roughed up manually, etc. Still, I wish these things would just go away. There's a reason why utility crews use them to place telephone/electrical poles in the ground!