A large black snake lay motionless on the moss beside the trail just past the signboard for the Snyder-Middleswarth Natural Area. My hiking buddy and I had driven over this past Saturday afternoon to pay homage to one of Pennsylvania’s most spectacular old-growth remnants before it is altered forever. The air was crystal-clear, adding to the cathedral-like effect of shafts of sunlight reaching down through the canopy.
Just past the snake we began to find spectacular, red and orange polypores — the hemlock varnish shelf…
and the fungus beetles known as Megalodacne heros, colored to match. Those that weren’t busy eating were busy mating, true to their family name Erotylidae, and some managed both at the same time.
In fact, things are looking very good for hemlock varnish shelves and the beetles that love them at Snyder-Middleswarth for a decade or more to come. That’s because the hemlock trees are dying,
300-year-old giants falling victim to an insect barely bigger than the point of a pencil, the hemlock woolly adelgid. Their egg masses are often compared to the ends of cotton q-tips, an image more in keeping with the kinds of places where human beings go to die.
The eastern and Carolina species of hemlock are especially vulnerable, though occasional individuals do show resistance. It may take a century or more for their native predators and diseases to catch up with the adelgids and bring them more into balance with the eastern forest ecosystem, though they will probably always remain an outbreak insect. In a few centuries, we may have new old-growth hemlock forests in Pennsylvania.
But in the meantime, another climax species — yellow birch — seems poised to take over at Snyder-Middleswarth. Almost every fallen hemlock log we saw bore a thick fur of birch seedlings. Forest ecologists refer to these as nurse logs, which is a bit misleading: birches and other tree seedlings prefer to sprout on logs not because they are fertile nurseries — they aren’t — but because they offer relatively sterile refuges from soil microbes inimical to seedling growth.
The word seems to have gotten out that the giants are dying — that’s the only way we could account for the dearth of visitors on a perfect Saturday afternoon in early summer. We walked slowly along the trail above the inaptly named Swift Run, looking at everything and listening to the songs of hermit thrushes and winter wrens. In three hours, we only heard a couple planes go over. It’s a deep ravine far from any highways — one of the quietest spots in all of central Pennsylvania.
I renewed my acquaintance with several plants that I don’t get to see too often, including starflower (Trientalis borealis) and mountain holly (Ilex montana). And we encountered botanical oddities like the fern fist above, one of several we found, probably the result of some wasp or another hijacking the ferns while they were still unfurling in order to make gall-like brood chambers from the crippled fronds. (If anyone has a better guess, I’d like to hear it.)
But mostly what caught my eye were the dead and dying hemlocks. I know that new hemlock seedlings will sprout up after the adelgid population crashes, and some of them may even survive future outbreaks. But it will be a long time before the forest once again has trees with this much character and presence.
It was 7:00 o’clock by the time we made our way back to the parking area. Much of the ravine was already in shadow. I turned around for a last, long look at hemlocks bathed in cathedral light.
This makes me think of the mountains of western North Carolina, going all silvery with dead balsams…
I love the frolicsome fungus beetles, and that wonderful rainbow whirl.
But what sort of snake is it??? The precise taxonomy of all else throws its anonymity into sharp relief.
I love the way one of the hemlock varnish shelves seems to have grown around a branch and sort of resealed itself afterwards. Or at least that’s what it looks like.
It’s a black snake, Elaphe obsoleta. I tend to supply scientific names only when there’s a strong chance of confusion, and/or I find the translation interesting.
Yeah, that fungus has grown around a branch and several twigs.
(o)
Hi! Nice set of pix. Your comment about people not coming to see the dying giants struck me…almost like a WWF of trees syndrome(only the biggest baddest muthas are worthy) . Out here in Oregon there is a lot of argument on how to take care of the forest, and a lot of times old growth is presented as the “Shangri-La”, the be-all and end-all. Old growth trees are certainly awe-full, but the fact is that forests are cyclical, and is perpetually becoming. There is a beautiful forest near here that was “glassed” in the 1930’s by terrible forest fires, and today it’s well on it’s way to being what it needs to be(the average person looking at it today would call it “old growth” and never guess there had been a fire). I’m glad you made the point that when the cycle of bugs recedes, the trees will grow old and tall again in another 200 years(as long as the forest of snags and young trees is not viewed as “ruined” and vacation homes built). Glad to see a natural place in Penn! I hope those places survive and are left alone to become.
PS, I forgot to say that I don’t think you have the WWF tude, just that I see it in a lot of “other people’s” comments I read and hear around here(in PNW I mean).
celeste – Well, that’s one reason I write posts like this: to try and keep making the point that natural forest ecosystems are about more than just big trees. In fact, it’s a good bet that Pennsylvania has as many acres in unrecognized old-growth remnants as in protected natural areas. Foresters themselves (who invented the term “old growth” as a pejorative term, let’s remember) have tended to focus on the obvious sites, which in our state means hemlocks and white pines. Old-growth chestnut oaks (for example) are much less impressive, and tend to occur on hard-to-get-to talus slopes near the crests of ridges.
Your point about perpetual becoming is well taken. The climax forest model derives from studies of eastern forests, which are unusually stable due to the low incidence of catastrophic natural disturbances. In most other places in the world, the concept of a climax forest isn’t very useful, I’m told.
Thanks for commenting.
Enjoyable post, Dave. I’ve never been in a hemlock forest, but can imagine how beautiful it must be based on how much I like the individual trees.
Isn’t there some type of control for the adelgid? How do you feel about that?
Laura, if you’ve never been, you’d better not waste much more time!
There are a couple of biological controls, but they haven’t really taken hold yet. These things can take a while. It took over a century for the gypsy moth’s natural controls (a fungus, a virus, a wasp) to catch up with it.
Stunning photos and interesting insight into this ecosystem.