In September, a developer will be moving several Amer. hollies, magnolias, et al. w/96 inch treespade. I recommended root pruning now. The spade operator said don't root prune, but do fertilize (talk about a conflict of interest: he included a price to fertilize). He says root pruning does no good. I find this hard to believe, but can't say I have ever had the opportunity to do it… usually I have been under the gun to get the trees moved and had no time to consider such things as root pruning.
Anybody have thoughts on this?

Reply to post by Ed Milhous, on April 02, 2000 at 11:44:38:

Since there is plenty of horticultural evidence to justify root pruning, have the spader justify not root pruning. To prove your point you can go to texts that talk about nursery production techniques.

The same arguement can be used for fertilizing. Show me why fertilizing is needed. Do a soil/tissue test to prove a lack of nutrients.

When nurseries plan on moving large trees they will prepare by cutting two quarters of the roots one year and the other two the next and then tranplant the third.

All of the preperation work will be justified by a higher survival rate.

You might contact Bailey Nurseries in St. Paul, MN to find out thier philosophy on transplanting. Even thought they are dealing with liner stock up to about 3" DBH the principals are the same.

Tom

Reply to post by Ed Milhous, on April 02, 2000 at 11:44:38:

Ed, just a guess.... the efficacy of root pruning might have a lot to do with the size of the stock vs. the 96" spade dug ball. The sales pitch on tree spades is often "the tree won't even know it's been moved." That might be true at some size where few roots are actually cut. At that size fertilizing or maybe even just irrigating within the ball size might produce more root growth in the ball than root pruning... especially for the cost.

As tree size gets larger this would less likely be true.

Reply to post by Ed Milhous, on April 02, 2000 at 11:44:38:

Ed,

Thought to ponder.... fall transplanting of Magnolias is starting out with about six knocks against you. They resent moving to begin with (the whole family does) but the best time is just prior to bud break in the spring, it goes down hill from there.

Wayne

Reply to post by Wayne, on April 02, 2000 at 11:44:38:

Agreed.
These would not be my choices to move anyway (saucer manages to perform about 1 year in 3 around here); and they are BIG.
But, hey, I am just a poor dumb arborist, and we have developers and LA's to make the important decisions.

Reply to post by Ed Milhous, on April 02, 2000 at 11:44:38:

On Monday the Urban Forestry Club at the University of Minnesota had Bonnie Appleton speak on nursery practices.

She talked about prepping trees for spading. If you chose to root prune, be sure to cut the roots at a diameter smaller than you plan on moving. If you cut the roots and they regrow tips then you come in and cut at the same place you will loose all of the new small tips.

The other thing that she advised is to set up a drip irrigation inside the diameter that you will move. This will enable the tree to grow more roots to the inside of the root ball. Of course, irrigate after transplant.

Tom

Reply to post by Tom Dunlap, on April 02, 2000 at 11:44:38:

Good point, Tom. I have seen people root prune the tree with a spade the same size as the one they planned to move the tree with later, and always thought it to be rather counterproductive.
Bonnie told me once that the drip irrigation idea is about as effective as mechanical root pruning, at least in dry areas or seasons.