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Deborah and I went down to the Rock Furnace trail last Sunday afternoon. There was abundant sunshine, but the air was shockingly cold when you stepped into the shade. The wind was also steadily blowing at 10 to 15 mph, so the shelter of the ravine through which the trail runs, in spite of its shade, was most welcome. There were only a couple of other people out on the trail, so it was a quiet, peaceful walk.
Sounds of rushing water surrounded us. Down below, in its narrow channel, Roaring Run cascaded along over room-sized rocks and joined the smaller Rattling Run at the old, concrete bridge deep in the hollow. Rattling Run had come in via its picturesque drop over Jackson’s Falls just a quarter of a mile or so up a side-trail that is now marked “private property.” The abundance of rain last month (over eleven inches!) had filled the springs and all of the flowing channels. Gravity, then, was pulling all of the water towards the big rivers!
Back in the early Nineteenth Century there had been a tavern and a couple of cabins here in this hollow. There is an old, stone-lined well just off the trail and a bit further down the stream there are piles of tumbled rocks that had once been a functioning iron furnace. Trees on the surrounding hillsides were repeatedly cut to make charcoal, and limestone and iron-bearing sandstone were tumbled and carted down the surrounding slopes to feed the furnace. The resulting pig iron was taken a mile further down Roaring Run to the Main Line Canal and then barged down to forges and mills in Pittsburgh.
This furnace, like most of the scattered furnaces throughout the East, had a very short functional life. It quickly exhausted its ore and wood resources and was eventually replaced by more efficient systems.
Everything is dully colored down here. The forest floor is littered with dry, brown leaves, and the gray tree trunks (mostly red maple, yellow poplar and beech) stand in dense copses, incredibly uniformly sized (6 to 8 inches dbh) all along the trail. These trees are recovery relics from the wholesale cutting needed to feed the old furnaces. There is a stand of eastern hemlocks along the stream that may be a remnant of the hemlock forest that would have dominated this cool, wet ravine before the iron furnace was set up. Out in the surrounding acres of hardwood trees, occasionally a small hemlock can be found growing all by itself. These small trees are probably surprisingly old! If they get three or four hundred more years, each of these hemlocks will be centers of ecological “crystals” that will merge into a new hemlock forest. All of these maples and poplars,then, will just be distant memories in the humus.
It’s easy to spot the hemlocks. They are bright stabs of green in the brown and gray of the forest. Looking closer you can see other patches of green, too. Evergreen wood fern and Christmas fern, and polypody fern up on the sandstone boulders have kept their chlorophyll all winter. Also, many of the rocks and some of the fallen logs and stumps have moss growing on them. Many of these moss mats have recently sent up sporophyte stalks (they are so new that they are still green!). The knobby capsules on the tips of the stalks will make spores that will disperse in the wind or in the rain and let the moss mat slowly increase its density and steadily expand its edges.
There are no spring wildflowers yet. No colt’s foot even at south facing hillside beside the McCartney #6 gas well. This is the spot where the first blooms are usually seen. No spring beauty, either. There are a few isolated clumps of grass left over from last year’s growing season. The water in the shallow drainage ditches is cold and quiet, too. No insects or amphibian eggs or tadpoles. Nothing new for this year, at least not in the view of our weak human senses.
(The next day Deborah and I headed up to Harrison Hills Park)
It was, once again, sunny but cold (only 38 degrees when we started). Much less wind today, though, which we greatly appreciated since we would be walking out in the high, open meadows of the park. We were here to check our bluebird boxes and make sure that they were ready for the coming nesting season.
We parked at the Environmental Learning Center and walked down the service road, past the still covered purple martin houses. We were alert for any sign or sound of early arriving field sparrows and also watched for any bluebirds that might have overwintered, but we saw neither.
The sunlight was intense and was playing tricks on us. The tall yellow poplar trees on the edges of the purple martin field and along the access road were covered with their old, brown, cone-shaped clusters of samaras making the outline of their crowns quite distinct from any of the other types of surrounding trees. The sunlight, though, reflecting off many of these samara “cones” made them look bright white, and the intensity of the color made these old, dry outlines of flowers look new and fresh! I had to mentally walk through my sylviculture to reassure myself that, no, these trees were not in early flower. We would have to wait for mid-April (when the poplar trees were all leafed out) for the colorful flowers of these “tulip trees” to open up.
A vulture flew overhead wobbling in the rising thermals. The sun reflected brightly off of its bald head, though, making it look white, too. For a few seconds, in spite of the uplifted wings (shaped into a “V” (for vulture!)) and uncertain flying pattern we thought we were looking at a bald eagle.
Our bluebird boxes looked good. A few of them had obviously had some overwintering occupants. We cleaned out some dried fecal pellets and even found a few bright blue feathers. The non-migrating male bluebirds must have packed into these boxes for communal shelter and warmth during the winter months.
Up in the High Meadow (the field where most of Deborah’s and my assigned boxes were located) we made a surprising discovery. On the north edge of the field, tucked into some bushes, there was a nesting box that we hadn’t noticed before! Three years ago our volunteer group took over the park’s set of nesting boxes that had been built and set up by a Boy Scout troop in 2005. We inventoried all of the boxes, repaired many of them, and assigned them numbers. We have had three years of remarkable success with bluebird nesting! This box, though, had been missed!
I could not open the box (the locking nail was tightly fixed) but could see via the entrance hole that it was packed full of nesting materials. I slipped it off of its pole and brought it home to clean it out and make some repairs. When I opened the box down in my garage I found that it was packed full with a pound or two of soil and leaves and small sticks. It was a nest construction that I had not seen before! I used a putty knife to loosen the edges of the nesting mass. As soon as I inserted the knife blade a very energized, white-footed mouse shot straight up out of the nesting box and hit the floor of my garage running. He raced under a stack of old two-by-fours and was gone.
At least I know what kind of a nest it was! I wish that my cat, Mazie, had been there to help me with that mouse!