The Root of the Problem

[Grenfell]

Hey guys,

Long time no see!

I had a generic root question...I know root tissue isn't compatible with trunk tissue and you can get girdling.

What I am wondering is...will crossing roots merge? Or do they girdle each other as well?

I have a newly planted red oak (planted at flare) and it has a few roots that circle near the base. This would be at or below the flare. So I am wondering if I should leave them or cut off now?

The tree is from a nursery, I wasn't able to source a wild one this time.

TIA!

 

[S Mc]

Grenfell, are you talking about adventitious roots above the main structural roots? or the main root structure itself? Was this a container tree or ball and burlapped?

We just read an interesting article that pointed out that roots regrow in the same direction they were cut. Primary roots growing away from the tree will still go away from the tree. Secondary roots growing at a 90 degree angle from the primary root will still grow in that 90 degree direction after being cut.

With that information, if you cut off these roots, I would be wanting to be sure I cut them off to encourage growth in a direction that will minimize problems in the future. Basically, the same principles as when redirectional pruning a branch on a tree.

This same article pointed out that not all girdling roots on young trees become an issue. Their illustration was Norway maples as opposed to Red maples. Red maples have a great many more girdling roots as young trees, but they do not persist. As opposed to the very common instances of massive girdling roots on Norway maples.

To answer one of your other questions, red oak roots graft. This is one of the means that Oak Wilt can be spread from tree to tree.

Sylvia

 

[Grenfell]

This was a container tree from a nursery. You'd think I'd learn and just go get a wild one, but I don't have as much free time (two young boys, third on the way) as I used to.

It has a grafted root stock, which I cleaned up and planted at the flare at the time of planting. It's growing well. I can see a couple of first order roots, with a buttressing structure already evident.

What I am referring to are some smaller, apparently adventitious roots from the side. They have a circular, girdling orientation. However, they do appear to originate at or near the root portion of the tree, hence my question. I'm guessing they formed while the tree was buried (deeply) in the store container.

So I'm basically wondering...leave them be and they'll simply grow/graft into the existing expaning root structure, or try and prune now? This is the tree's first growing season following planting, so I'm reticent to take any actions unless I have to. It has leafed out at this point. The leaves are close to full size and are darkening from the initial light green to the fuller, deeper green state.

 

[Grenfell]

Ok, here are some pics...

 

[Grenfell]

Closeup of the roots.

It looks like the small root at (1) is adventitious?

Will the two small roots at (2) pose an issue, or will they combine/graft into existing roots?

 

[S Mc]

These do look like adventitious roots. I would not take off No. 1, as it is growing out from a good location without appearing to have girdling tendencies.

I would cut the two small No 2s but I would like to see for sure from where they are originating to determine where exactly they should be cut. The upper No. 2 looks like it is laying underneath No. 1. Can you tell?

Both of the No. 2s look like they are overlapping a root (on the right side of the photo) that is more desireable than they are themselves.

Sylvia

 

[treeseer]

These do look like adventitious roots. I would not take off No. 1, as it is growing out from a good location without appearing to have girdling tendencies.

I would cut the two small No 2s but I would like to see for sure from where they are originating to determine where exactly they should be cut. The upper No. 2 looks like it is laying underneath No. 1. Can you tell?

Both of the No. 2s look like they are overlapping a root (on the right side of the photo) that is more desireable than they are themselves.

Sylvia

:agree2: with S as usual. )

you do need to expose more--garden hose works well for this.clip everything that girdles stem or buttresses. the tree is so young i would wait til ideal time which is september.

"Red maples have a great many more girdling roots as young trees, but they do not persist."

the article really did not say this did it? not persist? what happens to them?

 

[Grenfell]

Thanks Sylvia, Treeseer. Nice chatting with you both again.

I'll expose a bit more (with a hose) and take a look. Then perhaps prune in the Fall.

Cheers.

 

[S Mc]

:agree2: with S as usual. )

you do need to expose more--garden hose works well for this.clip everything that girdles stem or buttresses. the tree is so young i would wait til ideal time which is september.

"Red maples have a great many more girdling roots as young trees, but they do not persist."

the article really did not say this did it? not persist? what happens to them?

Yes, I thought this very intriguing as well. The article cited is "Girdling Root Formation in Landscape Trees" by Gary W. Watson and Sandra Clark. (For easy reference this is one of the compendium articles in "Tree Selection and Planting".)

The exact reference: "Young Norway maples have an average of four girdling roots per tree when examined a few years after transplanting, and sugar maple have a similar number. Red maples have more -- nearly twice as many. Then why are crown decline symptoms common only on Norway maples as mature trees? Girdling roots may not be long lived in red and sugar maples. Excavation of root crowns of mature sugar and red maples revealed very few girdling roots and those found were relatively small and young. Girdling roots of similar-aged Norway maples were much more numerous and nearly as old as the trees. Apparently, the girdling roots that develop on red and sugar maples as a direct result of transplanting are not usually long-lived, but the reason is unknown."

Perhaps species genetic variation? Above ground growth characteristics are persistent and vary species to species, so perhaps this is part of the answer. But I would still remove them when possible.

The other point this article makes is the regrowth of any severed root. A root will regrow in the direction it was originally growing, so if you cut a secondary root that was already growing at 90 degree angle to the stem/root it was girdling, it would regrow in that same direction. Hence the problem perpetrates itself.

This would be why it is important to make root cuts at nodes similar to proper branch cuts, to redirect the growth in a more desirable direction.

Picturing overtrimming a Norway maple...it can go crazy with regrowth if too much is taken off. In a nursery harvesting system, say field grown to ball and burlap...they have taken off a tremendous amount of root growth. With a tree spade there is no careful cutting, just internodal wherever. And the amount of roots lost is 80 to 90%.

If you take off that much top growth on a tree, and it survives, the regrowth is exaggerated and cannot help but grow in undesirable directions, interferring and crossing over, presenting problems for the future. Some species worse than others.

Sylvia

 

[treeseer]

"Girdling roots may not be long lived in red and sugar maples." is the wording in the article "Red maples have a great many more girdling roots as young trees, but they do not persist." was the paraphrase.

The article was based on a very limited sample, so its application is limited.

"This would be why it is important to make root cuts at nodes similar to proper branch cuts, to redirect the growth in a more desirable direction."

True, but regrowth can also be from further back on the root, and is often perpendicular. One more reason ANSI says the flare should always be visible.

 

[Grenfell]

Hmm...interesting.

I have another somewhat related question...have either of you read any literature citing the long-term fitness and success rates of grafted hardwood trees vs. seed-grown variants? i.e. those grown from seed and those grafted to a root stock?

I take it the reason for my asking is obvious...

 

[S Mc]

"This would be why it is important to make root cuts at nodes similar to proper branch cuts, to redirect the growth in a more desirable direction."

True, but regrowth can also be from further back on the root, and is often perpendicular. One more reason ANSI says the flare should always be visible.

The article points out the primary root growth direction vs the secondary root growth direction. Secondary being 90 degrees off the primary. Then tertiary growth being perpendicular again.

Makes you wonder why any tree DOESN'T have girdling roots galore.

And absolutely agree, Guy, the flare and origin of the roots you wish to cut need to be exposed so you, in fact, know what you are cutting and why.

"...have either of you read any literature citing the long-term fitness and success rates of grafted hardwood trees vs. seed-grown variants? i.e. those grown from seed and those grafted to a root stock?"

Not specifically, Grenfell, but I feel a googling moment coming on.

In fruit trees, you cannot reproduce the original cultivar from seed. It has to be grafted. So if you are trying to reproduce specific traits from one generation of hardwood trees to another, this would hold true. The seed variance may not hold true.

There appears to be a difference of opinion on whether seed variants are inherently stronger than grafted cultivars. Since cultivars don't "seed" true, they have to be grafted. Ergo, proponents of grafted species are, of course, going to say their grafted trees are quite sound with a high success ratio.

Seed grown variants may indeed be stronger structurally with no graft to reject, but they will not reliably reproduce a specifically desired trait. So simply may not be an option if you are trying to sell a specific cultivar.

More googling this afternoon...

Sylvia

 

[vincem77]

A few posts late, but here are some pictures of 40-50 year old maples in my backyard. They were both pulled out of another yard and transplanted at 2-3ft. Camera lens was dirty so it didn't like to focus right.

Silver maple shows no signs above ground of girdled roots

Sugar maple shows girdled roots most of the way around the tree. Most were not visible 10-15 years ago. Still seems to be growing fairly well? The dark spot on the trunk is from bark that broke off. Sometimes my dog gets hungry when im not looking.

Tried moving some dirt to show more detail for this one but just made it worse.

 

[treeseer]

that sugar maple root looks low enough to be probably grafting. the rest of those buttress roots look very good. wish all/most of the trees I looked at
looked that good.
And Sylvia yes flares must be visible before pruning is planned, but more importantly they all must be visible all the time anyway, per ANSI.