Brushpiles: Stiltgrass, Knotweed, and Riparian Buffers

Posted: January 7, 2014

Brushpiles is the opinion page of Forest Leaves. It’s a place for you to write in and share your reactions and thoughts about recent articles in the newsletter. This piece was written by Bill Paxton in response to articles in the Summer 2013 issue of Forest Leaves.

In Defense of Stiltgrass

Having read the article about how loggers, developers, and gas line rights of way clearers prepare the perfect habitat for Japanese stiltgrass, then carry the seeds from place to place on the equipment and very effectively seed their jobsites with a great ground cover and erosion control for zero expense… I am wondering why there is such a panicky fuss.

I hope you are young since I probably won’t be around to collect my winnings on this bet, but… I bet you in twenty years, you will have the typical crown cover of secondary growth hardwoods, just like the fallow farm fields and pastures filled in with goldenrod as is typical of any successional process in Pennsylvania.

Just keep saying to yourself, “In order to have a fifty-year old growth of trees, you have to wait fifty years!”

Your management options, of course, would be to spray the stiltgrass and kill all the residual native and non-native weeds (and of course, native wildflowers). Or, take another grader in there and after clearing, plant it with rye grass or some wildflower (from God knows where) mix. And that won’t play havoc with the soil? Or you can go in and plant it with shrubbery as they do on coal mine reclamation (European alder or autumn olive as they did in the past – hopefully not), and they would not disperse? Or you could have kept the equipment out of there in the first place and you would see no stiltgrass proliferation?

But it might be best to just have patience and faith that the forest will heal, the soil will settle, successional plants will grow and die for ten years to get enough topsoil for tree seedlings to germinate and come up through blackberries and all the weedy shrubs that WILL come up through the stiltgrass, and then make way for the tree seedlings, just as they have done for eons.

I wonder where the idea comes that black cherry, red oak, and white ash are primary successional species. We’ve watched black locust, sassafras, and black gum act as the pioneer species for many years. Then come in the red maples, etc., etc… so don’t panic.

And in twenty years, you can send my winnings to my estate.

Now as to Solving the Knotweed

As every fireman knows, if the temperature is below the flash point and there is no available oxygen, the fire goes out!

Plants need nutrients from the soil and leaves to make the food to keep the roots healthy. If both roots and leaves are good, then most plants thrive. Knotweed is especially sensitive to cold and badly burned by late frosts. It seems to me that if frost in the form of carbon dioxide extinguishers is applied several times after leaf recovery (and who doesn’t need to spray insecticides and herbicides at least 3-5 times?) that there will be no leaves to make food and the roots will diminish and after two years of this approach the plants will die.

Then of course you will be looking at or living with the ash piles, the creek bank rip-rap, the rubble of reclaimed soil, because knotweeds (Japanese knotweed (Polygonum cuspidatum) and giant knotweed (Polygonum sachalinense)) are the only plant that can grow there!

By the way there are many other “knotweeds” that do the same thing on a smaller scale – smartweeds, tearthumb, bindweeds, knotgrass, climbing false-buckwheat, jumpseed – all of which are very aggressive.

If we could learn to appreciate aggressive plants that cover our manmade scars, we could reduce the big billion dollar expense to zero. And, if you have the wisdom to do this, I’ll send you a quart of knotweed honey (made by bees, which aren’t native either), and an answer to that question I get late in every summer, “What are those beautiful cream-colored flowers along the Loyalhanna creek and the railroad right-of-way and the highway and railroad ash sides, and that abandoned industrial site?” I tell them, “It is the knotweeds covering the scars of our progress…”

Riparian Buffer Solutions

The obvious solution to riparian buffer effectiveness is to set the boundaries by state law and a lot of promotion as relates to the water flow widths, e.g., fifty feet on either side of a three-foot wide flow, seventy-five feet on either side of a six to ten foot width flow, and one hundred feet on either side of all remaining runs, creek, and river widths.

Next, you either enforce with No Trespass signs or fences, especially for farming, timbering, and grazing (including, of course, any industrial, commercial, or home site development). Then you let the place grow. It does not matter what grows. Save the “billions of dollars” by not doing the laughably expensive and useless things that are being done, for example, cultivation, weed spraying, mowing, planting, maintaining the plantings, protecting the plants, removing the tree protection, selecting and removing any “invasive” shrub species, etc.

Since a buffer should remain a buffer forever, this is now a designated wild area. No logging or fishing, no trapping, no pollution from side flow, raw or otherwise, and no streambank maintenance or natural flow channeling.

Now you see what I have accomplished: First, all of those weedy grasses and forbs that hold the soil with their extensive root systems and filter unwanted, excess nutrients have a chance to get established. Second, the weedy shrubs of blackberry, black raspberry, crabapples, hawthorns, and the glorious grape vines will make the cover so dense in five short years that even the deer will not find it to be hospitable. Third, establish one long, straight, mowed, clear, twelve-foot wide pathway for the length of the area so that it can be monitored, and so that the deer will use the path and browse the edges, rather than disturb the secondary succession growth. Heavy deer browsing must be eliminated by having alternate-year open season (just like they did with crows).

Believe it or not, the proper plants will find their way to establishment. “You have made it; they will come!” You will have rushes, sedges, grasses, alder, silky dogwood, river birch, willows, sycamore, silver maple, elm, basswood, and the trees that one normally finds in the first one hundred feet of river banks. Then, when the riparian buffer is solid, the upland things that you were wont to plant, red maple, swamp white oak, pin oak, etc., will start after the floodplain species. Speed has no meaning here. This is not a “to be timbered” growth.

I find it very hard to believe that scientific persons who have made such careful studies never looked around to see that they were merely feeding the deer and killing the native plants with herbicide removal of “invasive weeds!"