This post was written by Olivia Schouten, one of our Hubbard Fellows this year. Olivia is an excellent scientist, with strong expertise in plants and plant communities, as you’ll be able to see from this post.
As a biologist with broad interests, I can usually find something to love in all living things, but I’ll admit that plants have a special place in my heart. This is probably a good thing, since I’ve spent the majority of my education and professional life cultivating my knowledge of plants. I’ve found that they are often underappreciated and often overlooked, which is a shame, because plants are some of the most amazing organisms out there (in my humble opinion).
Plants, in most places, not only form the basis of the food chain, but also provide the structure of habitat. A forest with towering trees is very different than an open grassland or a sparsely vegetated desert, and the animals that live there respond accordingly. Plants are eaten, trampled underfoot, exposed to the whims of the weather, and just generally beaten down by the world around them, all on top of competing with each other for resources and space. But while plants have it rough, they are also really good at persisting.
Trees are an excellent example of just how persistent plants can be. I was reminded of this earlier in the summer when I came across a grove of cottonwoods in one of our Platte Prairies while searching for musk thistles. At first glance I thought one of the cottonwoods had recently fallen and the leaves hadn’t died back yet. On closer inspection, however, I realized that the tree had probably fallen years ago, and instead of dying, the parts of the trunk that now contacted the earth had sprouted roots and continued on living. Branches had grown up from the trunk,and now looked essentially like three trees, all connected by the same fallen trunk.
Trees are clearly hard to kill, as anyone who’s tried to cut down a deciduous tree in your yard knows. Once the tree is cut you have to treat the stump with herbicide, otherwise the still-living roots will simply sprout again. Nearly every tree we cut here on the Platte to keep our prairies open needs to be treated with an herbicide. While it would be nice to not have to use chemicals in our stewardship work like this, that resilience of trees can also be a blessing. After the wildfire at our Niobrara Valley Preserve a few years ago, much of the forest along the river was killed. However, the oaks along the slopes are re-sprouting from their roots, as only the tops of the trees had been killed in the blaze. Because of this, these forests have a jump start on regenerating after the devastation of the fire.
Since I found that cottonwood looking for musk thistles, it’s probably worth talking about them and their own resilient strategies. As a biennial, these plants only have one chance to flower and produce seeds, so they produce thousands of them at a time. And they can fly. That’s not great for us, considering they are considered noxious weeds here in Nebraska, but as a strategy for this plant it certainly pays off.
But wait, there’s more! Even when uprooted or sprayed with herbicide, if the flowers on a musk thistle plant have been pollinated, they will still produce seeds! So when we control this plant, we not only cut off the root just under the ground and pull it out, we have to collect any flowers, or else nothing will actually have been controlled. This persistent ability of musk thistles makes things more difficult and time consuming for us to control, but you have to admit that it’s a cool adaptation, and in its native habitat, likely very useful.
So far these examples relate back to land management, and how the difficulty in killing plants affects our ability to effectively manage invasive plants in prairies. But we rely on these same tenacious qualities in our native prairies species as well. Chris talks a lot about the resilience of prairies on this blog, and a lot of that depends on the persistent nature of individual plants.
Consider big bluestem, a favorite of both cattle and bison. It can be cropped down again and again to within an inch of the ground over a growing season, but while such trauma might kill another plant, big bluestem holds on until the herd moves on and it gets a break, coming back taller and stronger the next year, until it’s back to full strength within a few years. In addition, even in those years that it’s hammered by grazing, big bluestem will find a way to flower, since all that short and weak vegetation around them makes for a good place to put out seeds.
Other plants may just find that conditions in a certain year aren’t for them. Maybe it’s too dry, or too cold, or the grasses around them are just too tall. Perennial prairie plants don’t let that stop them, as many will simply take a break, growing very little above ground for a year, relying more on stores of energy in their roots than anything else. To some, it may seem like those plants have died and disappeared from a field. But just wait, when conditions become favorable, most of those plants will show up again, just as strong, and benefiting from that strategy of waiting it out through the hard times.
Now, just because plants are tough doesn’t mean they’re invincible. If put under too much stress even the most stubborn plant will eventually die. Knowing how plants are able to persist can help us more effectively target those plants we don’t want, but also help ensure that our desirable plants always have a chance to let their persistent nature shine!
I’ve had to controlled trees without herbicide since my park district will not permit volunteers to use it. Controlling trees without herbicide takes a lot of patience. I cut, or preferably girdle, them in summer and repeatedly cut sprouts off from below the girdle. I have done this to some of the tougher invasive trees for four years and some still persist. The hardest to control species with this method are the non-native common buckthorn, white mulberry, and Bradford pear. There is one Bradford pear that I girdled and repeatedly removed sprouts from that has leafed out and produced fruit going on four years now. I think for really tough species it would be easier to cover the stump with a black plastic bag to prevent the sprouts from getting light rather than repeatedly cutting them. Needless to say … I can sympathize with the persistence of some plants. Many of the plants I am trying to control had been cut previously, had too little herbicide applied to the stump by staff, and were not killed. Yes, plants can be very tough.
Very nice piece of writing!
The first thought I had when viewing the Cotton Wood was what a great place to spend the night or day. The tree offers shade on a hot day, protection from the wind, a place to sit and dine on the evenings victuals . or a place to get up high in a buffalo stampede. To a degree surprises me there is no sign of a fire ring. I think I will try the black plastic that James mentions on my Walnut it would not work as well on a Black Locust or Buck Thorn. The trick is persistence. The method I use on Locust , girdle, in the spring just after leaf out after 6 month or so sprouts will appear around the tree. I wait for very wet conditions than dig the short distance to the root these are easy to pull back toward the base of the tree usually within five or six feet than I sever the root. I have exterminated many a Locust within three years this way. We use not chemicals what so ever on our land. It is a tangled web we weave or what is it some say once committed to a slippery slope there is no turning back.
Herbicide use is a complicated issue. I don’t think spraying herbicide moves a developing restoration forward. I’ve seen a lot of damage occur even by really good applicators. I have many photos of damage from herbicide spraying on my Google+ page.
I prefer things be pulled or dug out before they get out of hand. However, for things that are too much work to pull or dig out like large patches of reed canary grass and Phragmites a wicking application will eliminate the possibility of spray drift and reduce the risk of damage to adjacent plants. Although, I try to be positive about spraying when the adjacent vegetation that has been killed will come back relatively quickly.
A second option to wicking that might be useful in some situations is a foam applicator.
An additional situation I think herbicide is worth the risks is when applying it to cut stumps or girdles of woody species. It saves so much time and effort compared to repeatedly cutting sprouts that it cannot be simply dismissed.
The biggest risk to the restoration is it might be transferred to adjacent plants through root connections. However, if the correct amount is used the adjacent plants should recover.
I completely understand not wanting to deal with the hassle of needing personal protection equipment, the risks of chemical exposure, or needing to get licensed to work on public land, etc. I have covered plants I wanted to kill with black plastic tied around stumps long before the Hamilton’s applied for a patent and began marketing buckthorn baggies. However, if you don’t mind spending the money to get a pre-made bag then they are available at the following website. However, I should mention herbicide is less costly and works faster.
James, thank you for the informative follow-up post here. When I read your first post in this thread and that from Edward, I was a bit concerned that, while well-intentioned, the perspectives painted an incomplete picture. I too disdain the use of herbicides but have come to realize they are an essential management tool when used with care and discretion. Your second post here provides a very good perspective on this and alternate management tools for dealing with invasive terrestrial plants, thank you for adding it!
We spend a huge amount of time and effort trying to combat the effects of invasive species. If only decisions involving globalization of commerce actually considered all the potential impacts…
And thank you for the wonderful essay, Olivia!
Great photos once again. As for the fallen cottonwood, Isn’t Nature wonderful !
Wow, beautifully written article.
I too adore plants. Their persistence is in fact one of the qualities that makes me love them so. If you compare that to the journey of our lives, it makes sense – pushing through the tough times, the low points and the rough spots to persevere and keep on living well.
Thank you for sharing this! Olivia is quite a writer and talent. A very bright future indeed!