October storm: the pluses and minuses
Waves crash over the breakwall by Stephan Hogland
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Chel Anderson is a botanist and plant ecologist for the Minnesota Department of Natural Resources. She lives here in Cook County and joins us periodically to talk about phenology or what’s going on in the woods right now. Welcome, Chel.
Anderson: Hi!
Well, Chel, we had one big storm. Let’s talk about storm damage.
Anderson: Yeah, that’s a great topic, I think, very immediate, shall we say, since we’re right in the aftermath and getting a better sense of just what all of the impacts are that are easy to say. And, of course, one of the most obvious, besides damage to your home or your yard or local buildings, is all the trees down. And, there are a lot of trees down.
Oh, I’ve talked to so many people that basically had to carve their way out of their driveways. And, I know I did in a number of cases run into that and a number of people, particularly away from the shore, there were a lot of trees down along the shore, but this was back inland where you might not expect quite so much.
Anderson: Right, true, and I think it’s a great remind of how while things like the big blowdown in 1999 really loom large and for good reason in our minds. This kind of damage to the canopy trees in particular in the forest and woodlands is happening all the time and these smaller events, in terms of the area and mass that they affect, may be smaller and not as easy to visualize. There is still a tremendous—there’s probably literally millions of trees that in this storm were impacted whether or not they came down altogether or were damaged somehow would vary quite a bit, but there is a tremendous effect on the canopy trees in particular. And, to some degree, this is a very important process within forest and woodland ecosystems, because it brings larger woody material down to the forest floor which is utilized by many things and is very important to various functions within any forest ecosystem. But, of course, it can also have negative effects in that it can open up areas of light on the forest floor, which can make for significant changes to plant life that normally grows in the shade. And, in terms of long-term impacts of something like climate change, this is one of the effects that we anticipate we will see as a result of climate change here and that is something that is generally referred to as the thinning of the forest canopy. This will not necessarily happen in huge events like ’99 blowdown, but will happen as a result of more frequent, larger, more impactful storms, like the one we’ve just had, and take out canopy trees and bring more light to the forest floor.
I’m assuming those would be the leafy trees?
Anderson: Yeah, well, any tree that is growing at the top of the structure of the vegetation.
So, some of the white pines?
Anderson: It could be conifers; it could be deciduous species like aspen and birch. A storm at this time of year has a relatively smaller effect on our leafy trees, our deciduous leafy trees, because they’ve lost their leaves, so they present less of an obstruction to the wind. So, the wind is exerting less force on them than if this had happened two months ago when they still had their leaves.
Yeah, they wouldn’t have that kind of wind-sail thing.
Anderson: Exactly. So, the conifers—as a proportion of the total forest canopy out there—they’ve probably taken a larger hit than the aspen or birch, for instance.
A lot of spruce and balsam seem to come down. Does that have anything to do with their root structure?
Anderson: Well, in part. They do have very broad root systems, but so do many of our deciduous species. But, it mostly has to do with the fact that they present a lot of surface to the wind, compared to the other trees, and they’re less protected by the other trees, because the wind can sail through those bare canopies of the other trees. And, of course, the biggest effects on any species of tree out there are going to be the trees that are on the edge of something, because they’re going to take the brunt of the wind first and they’re going to be totally exposed to the force of the wind. If you’re a tree growing within the forest, then you’re sheltered by your fellow trees around you. And trees that grow on the edge, if they’ve started from the beginning growing on the edge, they develop extra special strength qualities of strength both in their roots and in their trunks and branches that help them, you know, resist and be more firm to the wind. So, that doesn’t mean they can’t be toppled, they can, but they definitely adapt to that as they grow, just like your tomato plants. If you grow your tomato plants inside before you put them out, and you never put them until they’ve got to be tall, ready, looking good, you put them out, they fall right over, because the plant has not been exposed to any jostling by the wind. So, the cells have not responded to that particular condition and they aren’t ready for it and they need time. Again, as I said, bring coarse, woody debris down to the forest floor is a very important thing and that’s not a bad thing, and having it there is a good thing. So, if you have stuff that’s come down in the forest around that isn’t in your way, other than if you have a huge area blown down around your home or something, don’t feel the immediate need or that there’s some ecological need to go out and tidy it up, because the decaying of that material on the forest floor is essential to a healthy ecosystem, and it helps prevent the big rains that we had, which is another component of this storm, from going like a bullet to the nearest stream or lake, and slowing down the water is something that this kind of coarse, woody debris as it decays becomes like sponges and it soaks things up and slows water from moving across the surface of the land when it falls so heavily like it did this time at times. Big storms like we had are the kinds that really can contribute huge amounts of sediment—if a watershed isn’t in good shape in the forest around it—it can contribute tremendous sediment loads that can really spoil spawning options for fish. And, a lot of that sediment, in a big storm like this, ends up in Lake Superior, which has a lot of near-shore spawning for species that, again, require areas of boulders and gravel and cobbles that are not covered with sediment and where all the spaces in between them aren’t filled in with finer sediments of clay.
So, in other words, with a storm like that, there was good news and bad news.
Anderson: Yeah, as with most things.
Chel Anderson, DNR botanist and plant ecologist. Thanks again for helping us understand what’s going on around us and putting the big October blow into perspective.
Anderson: You’re welcome.
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