Yes, you want to get more roots by bare-rooting rather than cutting the root system down small so you can lift an intact soil ball. The exception is the minority of species of trees that cannot have their roots exposed to air for any length of time. And like the others this minority will not like having their roots cut way back.

Yes, you want to dig wide, shallow holes and do not want to plant over loosened soil that the tree will sink down into later. The new area of loosened soil around (and not under) the tree should extend well beyond the ends of the existing roots at planting time. Do not stomp the fill soil down around the roots after the tree is in place - an apparently common tendency - as you are installing a living thing that occupies the humidified air spaces between the soil particles - and not a fence post. Growth of new roots into the soil around the planted tree will be most robust if the soil is loose and well-aerated. New root growth from the cut root ends will not start until the dormant winter buds at the ends of the shoots open in spring. At this time hormones are generated by these buds that cause new roots to be made and grow out from the ends of the existing roots. These quickly grow a comparatively short distance and then root growth is reduced again until fall, when there is a major stretching out of existing, intact roots - 60% of the entire annual total of root growth occurs at this time. This schedule means that your transplants will have reduced top growth the first summer, with normal top growth not returning until next year - after the big root push has occurred next fall.

Bboy,

Thanks for that info. I had not thought about extending the loose soil past the end of the roots. Makes sense. Currently in northern California we are on the end of almost a foot of rain so the ground is pretty much mud. Do you think this is aerated, enough and if not what would you suggest for improving the soil. Based on the weight of a shovel there is not a molecule of air in there anywhere. .

In terms of keeping the tree upright do you recommend staking rather than packing down the dirt?

What is your opinion on lining the receiving hole with compost or horse manure or ?

Thanks again for sharing your knowledge. I had no idea of the root growth timing.

what i find that helps is heavily water the soil and the root flare before digging up it makes it easier in the heavy clay and it makes finding and uproooting the roots easier.

grizwald, I wanted to thank you for an informative and well told story!

Generally it seems most are for not amending the new site unless there is some deficiency. In that case I know I'm lazy and don't want to have to baby a tree to 80ft tall as it will get expensive.

If the ground is mud you need to wait for drier conditions before undertaking this operation. You do not want to mix any textural modification materials (bark, compost, peat, sand...) into the planting hole backfill.

I forgot to mention that grass is not your friend when you are airspading. If you have the time to put something over it and let it die back this is probably a good idea. Otherwise you can blast it with air and then pull it out manually. Another use for your rental teenager.
The stuff is amazingly tough and will make blowing out the dirt much slower. I suspect that the added air cannot be good to the little rootlets that one is laboring to preserve.

On a related note has anyone tried airspading while simultaneously sucking up the dirt with some thundering big vacume excavator or shop vac on steroids. The cost of renting a vacume excavator and a compressor would make this too expensive for me but given the number of pros on this forum I am currious as to how well (or poorly) it would work.
thanks griz.

Update on progress.
Have moved 6 tree now. One evergreen Oleander which has been sitting in it's new location for a bit more than a month without loosing a leaf. While it is certainly possible that it could still croak I am thinking it will be okay. The last tree I moved was a 30 ft Crepe Myrtle with about a 5 inch diameter trunk. Even with all the dirt off it's root it was at the extreme end of what my tractor will lift. I am waiting for the rains to stop before I try anything else. May need to use the trees to build an ark.

Griz, given the conditions you describe, I'd rather see a couple stakes holding up those transplants than to have the wet soil packed down around them.

Staking is fine-just get them off in a year or so.

+oM

Hello all,
In the continuing saga of airspading, all transplanted trees are staked and doing fine. Not a single death so far. The yard does look sort of like a military ropes course but other than that no issues.
HOWEVER I have now encountered a problem I did not foresee. In the latest attempt to move a very large oleander I have discovered that the root mass is too thick for the airspade to penetrate. Even when undercut I can't blow the dirt down or out enough to make the root mass pliable. Sooooo.....
Question. Has anyone tried using water (aka hydraulic) to remove dirt from tree roots. The downside as I see it would be the need for a great huge area to pump the dirt/water to and the subsequent hole in the ground. The tree has to go so if I can't get it moved it will be cut and I hate doing that.
thanks for your thoughts, Griz

@grizwald, it has been 7 years since you posted. How did your trees do? Did they all survive? I'm interested in this as i have a few trees in need of moving. If it worked, I'll have to find said teenager.... :)