Ice loading and tree failure.

Now is the time to notice which species of trees in your area is more prone to breaking with ice loads. Please report to this thread what you find out and what part of the country you live in.

Atlanta had a mild ice storm two weeks ago; a very early start. We had maybe an 1/8 inch buildup per side, which adds up to 1/4 inch total. The only trees that broke here were the water oaks (quercus nigra). These are the fastest growing oaks here in the South. They can grow up to an inch diameter in one season! They are in the red oak family. Their life expectancy is 100 years max.

A few pine branches broke of course along with a few magnolia branches. Both of these trees have a larger leaf (needle) surface for collecting ice buildup.

How are the trees faring elsewhere? Please let us know the specifics.

I've never seen any trees fail from ice loading out here. We must have some really strong trees!

I've noticed here, around New Orleans, that during Katrina, the trees that snapped (failed) very easily were pine, hackberry, tallow, pecan and oaks.
Would these tend to have the same failure tendency under ice?

Straight ice loading seems to be a minor issue here in the peidmont of North Carolina. The only climbing trees that I have seen consistent failure from ice is in the willow oaks. Most of these failures occur near the first limb beyond the connection to the bole of the tree.
That said when the ice is on the trees and then a strong wind storm comes up, which we had here several years ago, things get really hairy. I saw damage to all kinds of oaks, poplars, and pines. Cedars seemed to have no issue.

Climb Safe! I'd say it's best to avoid the ice all togather.

Icabod

We don't often get real ice storms up here. You need that collision of wet air and cold air - we have plenty of the latter and not enough of the former most years. If you're interested, I'll be digging around in the forest ecology literature on this over the next couple of months, and I can get back to you on what I turn up.

Icabod- willow oak is in the red oak family as well. What I have not seen recently is the nothern or southern red oaks fail here. Willow oaks are right up there in growth speed as the water oaks. Red oaks (Q. rubra and Q. falcata) clock in around 250 years life expectancy I believe. Possibly that has something to do with it.

MarkF- what do you think on this issue? Do the fast and short lived break easier? This is of course a very unscientific inquiry.

We rarely get ice in Atlanta. but when it does happen, we suffer greatly because of our large urban forest here.

A caution: I'm not an ice loading expert, but tree mortality is one of my areas of research, so be careful about getting me started...

Other things being equal, I'd expect fast growing and short-lived species to be more vulnerable. Fast growing often means lower density (and often lower lignin) wood which is both more fragile and more quickly subject to decay, as well as less allocation to defense (trees chemically defend themselves from bugs, fungi and anything else that noshes on them). An ice storm will often just magnify the effects of any pre-existing mechanical defects, and shorter-lived trees will develop these more quickly.

Then there are all the things that aren't usually equal. Decurrent (spreading) growth forms are more vulnerable. Evergreens (needles or broadleaf) are more vulnerable due to high surface area to accumulate ice.

Typical life spans vary by region. For example, up here a northern red oak (Q. rubra) would be pretty exceptional if it made it to 200 years; they are very subject to heart rot around here for some reason. Some species will also have different longevities in different parts of the same landscape.

Last week I was doing some pruning near Raleigh, NC and noticed that there were many cracks in the limbs. The bark was cracked at the point where the limb arched dwon. The cracks were perpendicular to the limb, going about half to 2/3 of the circumferance. I am positive that this is a result of the huge ice storm in that area about three, maybe four, years ago. Those cracked limbs are likely to fail later.

When I get home I'll be able to crop and edit the pics. I'll try to remember to post them.

Tom,
You'd be right. I did some volunteer work in the High Point area about 6months after that storm, and I removed alot of limbs with similar damage.

Most of the damage from that storm was also wind related. Ice first, then freezing rain then big wind, bad combo for our woody friends.

Next time you are in NC you need to call a brother!

Climb Safe!
Icabod

Tom,
Was there any tree species in particular you saw damaged, like the red oak family? I don't have a thing against red oaks, mind you. Damage seems to occur more with this family.

Last summer I was in the Poconos to do some motorcycling, and on the way, on Route80, was a path of destruction straight down the median that was so focused, my bud and I could only think tornado. But it was too straight, and it covered such a wide area, both sides of the highway and the middle. Couldn't have been that big - it would have been front page news everywhere, right?

Later someone told us ice storms of the winter of 2004 did that damage. The trees were twisted, wrecked and shredded. Never even occurred to us that it could be ice.

That title sounds like a description of my personality, and wallet, respectivly....

The ice storm I was referencing left alot of the decoratives, bradford pears, and dogwoods, "twisted and broken".

We had a 40' pine in the back yard lean ALL the way to the ground. Bent over like one half of a McDonalds sign. My kids were hanging from the top of the tree! It was pretty cool.

The pines did well, but everything else was trashed.

I don't recall seeing a lot of damage to the sycamores and poplars though...they seem to do worse in the summer.

Icabod

Greetings , The predominant species to suffer damage from ice or snow loading in blighty is Cedrus libani. A lot of big old estate cedars had legends attached that when a limb fell a male heir would die . so a lot had chains fitted to limbs by way of support. theres some spectacular "cedar of lebanon" on these estates's and you can still find the chains inside . usually with a chainsaw if your lucky enough to get to work on one !