Peak Brushy & The Missing Step
Since approximately 2019, I have had, at any given point, between 4 and 200,000 little raised bumps on my arms and legs. Here in rural America, that can mean something really dark, but in my case, it has more to do with pockets of bright sunlight.
The little bumps are the tips of thorns, mostly multiflora rose with some greenbriar mixed in for good measure, broken off and slowly working their way back out of the epidermis. Others like prickly ash and the rubus leave their mark, but they don't seem to stay with me like a sacrificial bee stinger the same way.
Sometimes I squeeze one out weeks or months after I acquired it, ~2mm tiny, shiny daggers that slip out with all the satisfaction of the worst acne from our teenage years. Gross, I know.
That's part of the reason I have started to question parts of the standard order-of-operations on which I am frequently deployed by landowners, at the behest of foresters or field biologists or soil conservationists carrying out their admirable mission to get better habitat on the ground through the red-tape of various cost share programs.
I have spent a lot of time this summer going back to look at sites I worked on over the last 7 years or so. I am forced to the uncomfortable - literally - conclusion that we are missing something in an important stage of a degraded forest's recovery.
Every site is different, but a lot of their ills are the same - a history of grazing, high-grade (taking all the best trees and leaving junk) logging, and invasive species.
It does make sense, then, that a lot of the treatments I apply look pretty similar - remove the undesirable trees, down to 1" diameter, so that the good stuff has more sunlight to grow.
The biggest problem I have seen is that a lot of the bad stuff is less than 1" in diameter, and it grows a lot faster than much of the good stuff. The foresters aren't missing it, but like everyone, they have to pick their battles knowing that most wood lots will only get a few stewardship treatments over the course of the ~120 year rotation practiced for oak retention.
At the time I need to be in the woods doing forestry work (dormant season), those little wisps of undesirable things aren't easily found and even when they are, foliar treatments (leaf spraying, the best method for smaller plants) aren't an option.
Following a timber stand improvement, I see a lot of properties follow a similar arc: year 1, a lot of interesting things show up, from weeds I'd see in a roadside to more conservative species, and lots of little woody things of varying interest.
Year two, things get very brushy. This is where foresters usually advise a landowner not to worry, it will shade out. They are correct. I want to stress that. Foresters, more than any other brand of conservationist, get the most flack for "getting things wrong," and I do not want to contribute to that.
This perception stems from trees simply not growing fast enough for most landowners to recognize what they are seeing. So I must say that what follows has more to do with the aforementioned battle-picking than "ignorance" of trained foresters with decades of experience, and I cannot stress that enough.
After a few years, we pass over what I call "peak brushy," and I start to see the really nasty thorny stuff start to die back, as do many of even the more shade-tolerant tree species as the first round of self-thinning hits. Some of the more shade-tolerant woodland herbs get a stronger foothold, and things start to stabilize again.
As (most) foresters see it, this works. A few weeks ago, I was standing at the foot of a massive slain bitternut I had cut, marveling at how quickly the surrounding walnut and white oak had filled in the canopy gap. The gooseberry shrubs in the understory looked like someone had sprayed them; I asked the landowner if he had done just that as I'd never seen this effect quite so dramatically, but he said no.
He also shared that, since I did the work, he had noticed his deer stand straps needed to be loosened every couple of months. I, with a longer gap since I'd been in the woods, noticed how fat the walnuts had gotten right away. The copious shagbark in the stand had also thickened, and the oaks had re-grown several lower limbs indicating they were growing better than before. Huge win.
But, in those canopy gaps where I expected to see oak regeneration, I saw almost none. We had a boom year in that cycle, too; I have seen ~5 year old oak seedlings all over northeast Iowa in other stands from that cohort, but here I had done timber stand improvement precisely to increase the oak composition in this forest, and I only saw seedlings in a few very specific spots: where the landowner had been mowing.
It makes me think back to this year's Iowa Prairie Conference, held in Dubuque this past July.
Keynote speaker Dan Carter (ecologist for The Prairie Enthusiasts) urged the audience to reframe how they think about grassy, sunlit ecosystems, which includes our oak woodlands here in the upper Midwest.
He urged us to consider the herbaceous layer as an "old-growth" component, as much or more than the trees. To that end, he stressed fire's role as a stabilizing factor rather than the "disturbance" title usually used in the discourse.
When I step back and put this in the context of what I observe in the half-decade following a typical timber stand improvement, I see a significant disruption in a critical part of the whole process.
Absent some intervention between my work doing timber stand improvement, and the ultimate harvest of that stand (which is the start of the next stand), the multiflora rose will be a real wrench in the gears of the actual forestry goals. It's present when I start my treatment, so they obviously haven't shaded out in the ~40 years since anyone did anything in this stand.
Suppressed? Absolutely. Problematic to the present condition in the woods? Not really, but that condition is about to change, and they will do a lot of damage before we pass through "peak brushy" back to the full-canopy open-understory status I see when I start on a stand. The trees will be fine in the long run, but the old-growth herbaceous layer, which is every bit as important as the trees to the overall ecology, will not thrive under this protocol alone.
When I open up the canopy to put some sunlight on those poor plants drowning in the shade, too often I see them get a season or two to gulp some air before a thorny shrub pushes their head back under. They'll live, but they won't necessarily flourish.
I can't reasonably expect a white oak to push through a multiflora rose growing in full sun. The real problem is that, until I made a site full sun, the multiflora rose truly didn't look like a problem. In ten years, it will have gone through the peak brushy cycle and won't look like a problem again.
Walking through a fully shaded woodland, I often question the claim that multiflora rose "shades out." You can absolutely still find many plants in a mature maple-basswood forest - they're just tiny. Once fully daylighted, these plants may double or triple in size in a growing season. Give it two or three growing seasons and, if there was any significant number of plants in there, a person will really struggle to re-enter the stand to deal with it.
There is usually some success recruiting oak, and it almost always works for walnut, but there is more to the woods than wood, and it's frustratingly common to see valuable woodland wildflowers and grasses come and go in the blink of an eye.
Little tiny bits of quality herbaceous vegetation exist everywhere; a little pocket of goldenseal in between blackberry canes, blue-eyed grass blooming at the edge of a buckthorn thicket.
But those little jewels disappear fast, and a site looks completely overwhelming even faster. People throw up their hands, especially if there's no cost share available to deal with it.
The result is a cycle of junk species, replaced by thorny shrubs, replaced by more shade-tolerant species and perhaps a few of the target trees regenerating, unless they were supplemented with planting (that succeeded) shortly after the TSI. Again, it's a success, but with just a little work, it could be more successful. It's less work than you may think.
Those big, giant, 11' wide clumps of multiflora rose are often no more than a couple of plants that got fat. For all of their inherent violence, multiflora rose is actually pretty weak. Timely chemical applications, or cutting down to ground level a couple of times in a year will keep it in check long enough for the better herbaceous layer to take hold, and that will resist the shrubby stuff very effectively. Multiflora rose, along with japanese barberry and honeysuckle (two other bullies that quickly dominate an opening) hates fire, if that's within a landowner's capacity.
Importantly, it's not forever. It's just through that vulnerable, immediate-post-disturbance phase. Absent fire, humans need to carry out that same stabilizing influence. I can and very much enjoy doing this work as part of my new profession, but I want to use this blog more for education than salesmanship. This is stuff that anyone who can carry a 1-gallon chemical sprayer, or a weed whacker, can reasonably achieve with a few days of work per year.
If the biodiversity isn't compelling enough, the financial math should be - look at the price of seed for wildflowers, or the price of seedlings and protection installation for trees, and you'll see pretty quickly that a few days annually managing through "peak brushy" yields an astonishing return on investment.
Remember what Dan Carter told a room full of plant nerds: the right kind of routine disturbance is stabilizing. Most landowners are on board with the disturbance part, it's the routine part that is missing from many landscapes. 100 years of non-management cannot be undone with one shot, but it does not take 100 more years either. Get out there and do your best, don't be afraid to make mistakes - our woods are resilient, and when we make ourselves a part of them and not just a passive observer, we can make them even more resilient.
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