When to root prune or not?

[Treelimbjim]

When do we try to abstain from root pruning stem girdling roots? I've several red oak transplants that have been in the ground over a year. I tried to get the contractor to prune them when they were transplanting.

Any published guidelines?

"Girdling roots on young trees should be cut." ...
"There are no set rules. You must look at every tree as an individual case and use your understanding of tree biology and common sense." -- p312, <u>Modern Arboriculture</u> A. Shigo, 1991

By most definitions, these roots restrict the flow of water and nutrients.

The sum of my experience and practice tells me one time of year to not prune as the tree is coming out of dormancy until the leaves are fully set. The other would be in the Fall, when the trees are 'shutting down' the leaves.

The trees in quesion have leaves that are changing color and texture. Why would one not remove roots when these roots will no longer be storage sites for nutrition because they will be removed? I'm of the opinion the tree can supply the canopy's needs without the roots targeted for removal in the early and mid Fall.

 

[tomthetreeman]

Jim, I have root pruned container Red and Scarlet Oaks in the Fall, and had basically the same results as if these trees had been dug and transplanted. It is my observation that root pruning when planting young trees in the Fall should be avoided on trees that are Fall digging hazards whenever possible.

Trees that are established and in-situ should tolerate root pruning much better, but obviously common sense should be employed as always. If you are dealing with girdling roots, you are probably looking at any negative effects of pruning as the lesser of two evils in most cases.

-Tom

 

[Treelimbjim]

Are Red Oaks on the Fall digging hazard list? [Where's the list?]

These were planted last June and are established and strong.

 

[cerviarborist]

Ed Gilman has an online publication addressing circling root pruning at http://hort.ifas.ufl.edu/woody/rootcirclingpine.shtml
As to the best time of year, particularly on younger trees, I think you've got a wider latitude, although it would seem that the tree would be better able to start compartmentalizing pruning wounds on roots during a time of active growth.

A TCIA article written on the subject by Guy Meilleur, available online at http://www.glte.org/documents/Meilleur_Guy_1.pdf has information that addresses your concern on timing.

"When to prune
The season during which stem-girdling roots are removed might influence the success of the treatment. We typically avoid pruning branches in spring and fall, when leaves are forming or falling, because these are times of increased sap flow and hormonal activity. Midsummer is a good time to prune deciduous trees, in part because the wound response may be more active than in winter. For all these reasons, midsummer may be the best time to prune roots. Scientists at the Bartlett Tree Research Laboratories found that summer removal of stem- girdling roots resulted in better diameter growth over two years than did fall removal or a combination of summer and fall removal for red maples under an irrigation system."

 

[RGus]

Excellent topic. My parents have a young honeylocust with a circling root which is not a problem now, but will be in a few years. I was wondering if it was ok to remove the root after leaf drop, or if I should wait unitl next summer.