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Invasive trees simply must go before they take over grasslands

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By Scott Rall Outdoors columnist
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By
Scott Rall

I planted a tree in my front yard about two years ago. It received more attention than any other tree I have ever put in the ground.
After I watered and nurtured the tree for two years, the winter of 2022-2023 finally killed it off. The tree had a tube on it to keep the rabbits away. When the snow got taller than the tube, the rabbits started in. Each additional snow allowed them more access to the tender bark. After the last snow, they had eaten all of the bark off the tree – all the way to the top branches 6 feet off the ground!
When I want a tree to grow, it seems like a herculean effort. When I don’t want a tree to grow, it seems like 10,000 of them will show up uninvited after just one rain.
I completed a CRP seeding for a gentleman in Murray County a few years back, and he called the other day to see if I could come out and look at a few trees that were starting to get a foothold. I was glad to help, and when I showed up, what I saw was not believable. One small section of the parcel had a few trees in it last year, and he had them mowed off in order to keep them from getting too big to handle. When I looked across this spot, I saw about 5,000 volunteer cottonwood trees that were all about 6 feet tall.  These trees went from mowed off to 6 feet tall in four months! Nobody watered them or mulched around them. There was no mowing around them to keep the grass from growing up and starving them for moisture. And yet there they were … almost to the size where you would need a chainsaw to deal with them. It would have only taken another year for these trees to become a big issue.
Many folks have a love affair with trees. This is any tree of any variety in any location. I don’t share this affliction. I have a saying that goes like this: The right kind of tree, in the right number, in the proper location are trees I love. Any other trees I hate.
When it comes to habitat management of grasslands, volunteer trees left untended will turn your grassland habitats into a forest in 10 years. The cottonwood tree is the most prolific and generally causes the most problems.
The rate at which cottonwood trees grow and their adaptation to survival makes them a top invasive species. Cottonwood trees have never done one single thing of benefit for any wildlife species.
Cottonwood trees are native to North America but were not present in the plains until man carried them in a wagon over the vast prairies.
The only thing a cottonwood tree has ever done of benefit was to soothe the soul of a human being as he/she sat under one and listened to the wind blowing gently through its leaves. When is the last time any of you have ever done that?
Raccoons, opossums and skunks absolutely love the hollows of a cottonwood tree, just as a bird of prey like a red-tailed hawk or other raptor loves to sit high in the cottonwood so as to ambush the ground nesting bird as it returns to its nest.
Once grassland habitat has 30-percent tree coverage, the density of reptiles and other creatures can be reduced up to 70 percent. 
Fire in the spring is the best way to control the invasion of unwanted trees, but not many folks are comfortable lighting up an 80-acre parcel with 20-foot-high flames. 
The only other reasonable method is chemical. This is also not all that easy as some of the best chemicals need to be handled with a great amount of respect and caution. Some of them are restricted use and cannot be purchased by everyone.
I use a 2-ounces-per-gallon mix of a chemical called crossbow. There are other names for this chemical, but you can spray it on the leaves if the tree is actively growing or spray the tree trunk all the way around about 12-14 inches tall. Almost all of this work is completed after the middle of July so as not to be banging around in the tall grass during the peak of the nesting season.
Managing invasive trees when they are little is much easier than a chain saw later, and in situations of really bad neglect, a skid loader with a hydro-ax on the front can be used for about $300-$400 dollars per treated acre.
Understanding how important grassland habitat management is to the creatures that live there will make you more understanding of why trees of the right species, in the right number, in the right place is a great motto. As for the rest, they simply must go.
Scott Rall, Worthington, is a habitat conservationist, avid hunting and fishing enthusiast and is president of Nobles County Pheasants Forever. He can be reached at scottarall@gmail.com

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