Tree Spade

[gab]

Looking for experience in details of moving trees with spades in a clay soil. I have always heard/read that the spade can glase the soil and produce a situation where roots have a hard time penetrating. Procedure is to "ruff up" the walls of the planting hole before installation. We have hired in someone with a spade and are being told no, that will cause to many air pockets and we should not do it and instead add some back fill with sand to fill any air pockets. What are your thoughts and experiences?
The tree is a 9" Taxodium distichum.
Gab

 

[John Paul Sanborn]

One problem you get with the backfilling is that yo get a dsicontinuity in the soil structure, which will inhibit water movement. Then again you will get this if you have a soil type in the ball that is significantly different then the native soil.

Water will have to pond up in the pit untill all the poers are filled befor going to the next layer of soil.

IMO the ISA recomendation of roughing the soil has scientific backing. You will allways get some air pockets when moving big lumps of earth though.

One thing I've seen done that I like is when spading trees into hard clay soils, after the instalation is done, make radial trenches with amendmenets to encourage radial root growth. Find the first order roots and radiate the trenches from their termination.

One step I feel is too often omited, doing a perc test prior to installation.

 

[gab]

We are lucky here, the tree is only being moved about 35 yards away.

 

[Kneejerk Bombas]

I agree with JPS, at least rough up the sides with a metal rake. As for air pockets, you're going to have some no matter what.

 

[DadF]

I plant almost all of our tree spaded trees here on campus with either a 44" Vermeer or an 80" Big John and have been doing that for more years than I care to say. So here are my observations:
The main thing is make sure that the planting hole that is dug is exactly the same as the tree that is being moved. Sounds easy and if the ground level and soil conditions are similar at the two sites- it is. But if the tree isn't planted right to start with then everything else is an uphill battle.
If the soil is really wet then the sides are easily glazed and should be roughed up. What I have found to be the most effective for around here(but we the campus is mostly built on a gravel layer) is to immediately water while planting. This serves two purposes-it helps to fill in the air pockets and also will keep whatever glazing might have occurred soft. When planting I will not pull from a planting site until I have reached a saturation point. Also you can use the hose to wash in any loose soil from around the edges.
Follow up watering can not be stressed enough. That doesn't mean wetting ground a little bit- that means saturating site every 10 days or so (assuming the tree was planted at the proper height to start with). I don't think we have removed a tree because it got too wet.
I like JPS's thoughts on radially trenching away from the planting hole and if the soil is really tight clay I would highly reccommend it.
We have also just started research with Cambistat and will find out in few years how well it helps 5-8"trees when they are being transplanted.

The floor is now open......

 

[gab]

You are all saying things that I have always thought to be true, just wanted to make sure that I was not the only one. I was most concerned with the companies idea of adding sand to a clay planting. I did not get to pick the contractor, but I will have to maintain the tree after planting. I will likely do the radial trenching, I have done that before and like the results.
I started to use cambistat last year as a post treatment of root damage after construction. The idea of reducing internodal growth while not effecting foliage mass is great. I am glad that one application lasts 3 years as it is expensive for large trees!
Thanks,

 

[DadF]

We also had a contractor with a larger spade in here last year and he used sand to fill in . I was not happy with it and the jury is still out on how effectively it works. The only advantage here here was that the soil was not clay but fairly loose sandy loam. I would still prefer to use the existing soil from around the planting hole to "wash" back in for air pocket elimination. Another thought ( and I think that Bartlett is doing research with this) is to use an airspade and loosen up the soil around the edgesof the planting hole and as far out the drip line or further. Sat in on a seminar last year where they have been doing this to rejuvenate growth on mature trees. Don't know why it wouldn't work on new sites either.

 

[DadF]

Bartlett had done some comparisons of drilling and composting, radially trenching and air spade stirring and found that the air spade always did the best. They had started this research when they were looking at some of the "ground fracturing" equipment that some people are trying to sell again

 

[John Paul Sanborn]

I've done the airspade 4 inches down surrounding the installed tree, just was not able to follow the trees in the long term.

 

[gab]

I have a high pressure hydraulic needle I use to apply mycorrhizae, maybe that would work around the perimeter of the hole with no amendments.
Gab

 

[Guy Meilleur]

Radial trenching for major roots is good, true, so why isn't deep tilling all around the rootball better?
That's part of aiming ALL the roots into amended beds.

Part of "roughing up" to avoid glazing for me is aerating/fracturing the pit with a pick. That speeds drainage, encourages deep root growth (the 9" taxodium I've moved had DEEP roots), while not changing pit contour much.

How much attention do you all pay to orientation?

 

[gab]

This tree will be installed in the same orientation that it is currently in. In "Aboriculture" by Harris he suggests, when doing large transplants with a spade, to be careful about too much loosening and enlarging of the new hole so as not to diminish support for the new tree. I guess trenching would allow some extra support between the spokes, and soil type would be a consideration as well.

 

[John Paul Sanborn]

Most of the people who trench these installs (that I know) do it with a big SP stumper and work thier way out.

I've done it where the install is a few years old and the tree is stressed. Cut into the root plate and then radiate out. Dump some root stimulating amendments in...