Great questions from south of the Mason-Dixon Line

Bluff Spring Fen

My recent post about Gladstone Fen prompted some of great questions from a couple of my good ol' boy readers (though I think Valown is a transplant to the South and may not be eligible for good ol' boy status. But then I'm about as Yankee as you can get, so I know little of these matters).

From North Carolina, Valown asks:

I've read that Fens are usually wet. What normally keeps them clear of shrubs and trees? I would think fire. But you would have to have a cycle that would include a dry period. Is that true, and is fire suppression the culprit there for these areas being overgrown? If you've covered this already in another post point me in that direction.

You're right, it is fire that keeps things open. I did a post on this about 2 months before you started coming by the Tapestry. You can see it here. Fens are not just usually wet, they are by definition wetlands. Because their saturated soils are fed by groundwater, they never really dry out, either. On the other hand, the soil doesn't need to be dry to support a fire- just the vegetation. As you can see in the photo above, the herbaceous layer in the wetland is very dense. The dried sedge stalks support fire very well. Remember my dramatic photos of the cattails burning with 40-foot high flames last spring? They were in standing water. We have previously had fire in still-frozen wetlands burn down to the ice line. It's all quite effective as a management tool.

From Pure Florida, FC wonders:

So, is this fen a natural feature?
It seems to take a lot of management and removal of invasive trees to maintain it.
Are the trees nonnative?

The fen is a natural feature. It's been around since the end of the last ice age. We know that the areas where we are removing trees from were open wetland rather than woodland because the soil in that area is saturated peat rather than loam. You can often tell areas where trees have invatded an open wetland follwoing fire suppression. The soil can't support the weight of many of the trees and they topple over. Sometimes this results in J-shaped trees. The base slowly falls over and the crown growth keeps curving upwards (sorry, no pics of that). So although many of the tree species here are native to this region, they are native invasives that that displace the fen ecosystem as a result of fire suppression.

Regarding your second question, most of us here differentiate between restoration and management. Restoration (in this case tree and brush clearing, as well as any activities needed to coax the native plant community along) is very labor intensive. Management typically involves periodic application of prescribed fire and is much less work. At Bluff Spring Fen, where I do most of my stewardship work, the majority of the fen wetlands are now maintained by fire only. This is typically our goal when we restore a bit of land.

Return to Gladstone Fen

On Sunday, Lorna Gladstone had another of her occasional workdays at Gladstone Fen up in McHenry County. I've blogged about this site a few times before, and in the late 1980s I was even the site steward there.

As you can see from the photos, winter still has a fairly good grip on northern Illinois, though there has been considerable snowmelt in the last couple of days. Lorna and her crew have been clearing a hillside seepage slope on the west side of the preserve. This is exciting to me, because back when I first started visiting, this is a portion of the fen that I never thought would receive active management.

Brush pile awaiting the torch

There were existing brush piles already created when we arrived. The days work consisted of burning a couple of them, and moving the remaining piles onto the burning ones. We wanted to minimize fire scars. We also had a couple of chainsaws cutting down some of the larger invasive trees. The rest of the work crew threw this freshly cut brush onto the fires as well.

Two bonfires, no waiting

This part of Gladstone fen was densely shade and filled with impenetrable brush when I first visited it. It's gratifying to see the first steps to converting it to healthy fen. Most of the trees and brush have been removed. The rest are slated to go.

Signs of spring- the first migrating sandhills of the year

Despite the wintry appearance, we got to see some signs of spring. The first flocks of sandhill cranes were migrating overhead.

The work crew

Gladstone Fen

Gladstone Fen

The first time that I was ever in the tropics was on a trip to Peru in 1986. It was an awesome trip, and I’ll probably post a remembrance of it sometime. My fellow travelers were a really interesting bunch of people, and I have maintained friendships with some of them. A year after the trip, I was sitting next to fellow travelers Lee Gladstone and his wife Gertrude at a trip reunion dinner. Lee knew that I was a biologist, but did not know of my work at Bluff Spring Fen. During the meal, he turned to me and asked what I know of fens. Now this is not a typical topic of dinner conversation, and I was a bit nonplussed that he would ask this. It turned out that he had just learned that he had one in the back yard of his weekend house in McHenry County. I wanted to see it, and a few weeks later they had me out.


















Oak woodland at Gladstone Fen

People frequently tell me that they own property with a rare ecosystem on it. Generally the ecosystem disappoints, but Lee and Gertrude’s place was the real deal. Their back yard contained about 6 acres of really nice fen. It was suffering from a lot of the degradation that fens in Illinois do- fire suppression, invasion by nonnative species, hydrology issues. Still, there was a relatively intact ecosystem and a surprising number of rare plant species. Eventually, I would also find a bunch of rare butterflies there, as well.

















View from the oak woodland into Gladstone Fen

Over the next decade, I would be the steward of this site. Lee and Gertrude used to have a bunch of friends from the city out to their weekend place. Leon and I would give interpretive tours of the fen, and then we’d all troop inside for a fabulous lunch. We held a bunch of workdays involving brush clearing and seed planting. We had several fine burns at the fen. Eventually the site was formally dedicated as an Illinois Nature Preserve. The site flourished under management. Since the late 1990s, I have been less able to participate in active management there.

This weekend Lee and Gertrude’s daughter Lorna invited us up for a special workday. We were joined by about a dozen other people, many of whom I know because they are active in the conservation community up in McHenry County. We were clearing out buckthorn, a very aggressive non-native tree that damages oak woodlands. We lit a bonfire and tossed the sapling trees onto it as they were cut down with chainsaws. It was satisfying work, and we made some great progress. Since her parent’s deaths, about a year apart and nearly five years ago, Lorna has taken up the mantle as site steward and is really doing a fine job.


















The bonfire

After the workday and the bonfires, we all went on back to the house and had a great lunch. I had been back to the site once since Lee and Gertrude had died, but this was my first time back in their house. I’ll confess that it put a lump in my throat. It was a different cast of characters, but the feeling was very similar. I had worried about what would happen to Gladstone Fen after Lee and Gertrude died (they were in their seventies when I met them), and I’m pleased to see it in such good hands.


















Part of yesterday's work crew. L-R: Will, John, Lorna, Leon

One afternoon about a year after Gertrude had passed on, I was walking through the Museum where I work and happened upon Lee sitting on a bench in one of the exhibits. Lee’s city home was just a few blocks from the Museum. He and his home care nurse had gone for a walk because it was a nice day, and had stopped in. I had no meetings or deadlines that afternoon, and got to spend about a half an hour chatting with him. He seemed much more subdued than usual. One of the things that I had always liked about Lee was his vibrancy as a person, and I remember feeling that his wife’s death had affected him very deeply. I will always treasure that particular conversation, because just three weeks later I would learn of Lee’s death.