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Deborah and I went down to the Rock Furnace trail last Saturday around noon. It was cloudy but warm (65 degrees) and quite humid. The weather forecast was for a zero percent chance of rain, but it sprinkled on us off and on while we were walking. There was no one in the parking area when we arrived, but five other cars pulled in and parked while we were out on the trail.
Down below the trail Roaring Run cascades noisily through narrow channels of rock and then spreads out and slows as it enters wider parts of its gully. It flows east and then arcs north to join the smaller Rattling Run at the old, concrete bridge deep in the hollow. Rattling Run comes 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 snow and rain this winter has filled the springs that feeds these creeks. There is a lot of water running in the streams!
We paused on the trail just before the climb up to the McCartney #6 gas well and looked down across one of the wider parts of the stream. A chorus of spring peepers echoed up from below and cascaded around us. The first peepers of the spring!
Spring peepers (Pseudoacris crucifer) are small tree frogs that live around marshes, ponds, temporary pools and small streams throughout the United States (except for the deep southeast). They are very abundant here in Pennsylvania. Peepers have sticky foot-pads that enable them to climb up the trees, shrubs, and tall grasses that surround their “home base” water sources, and it is from these perches that the male peepers sing out their distinctive, spring mating songs,
The peepers’ mating choruses begin in early spring (around here usually in mid-March). They usually start up fifteen minutes or so after sundown and typically go on for a four hour period. I am not sure why these peppers were calling so actively at noon last Saturday except that it was a cloudy day and finally warm enough for frog activity! Their release from the cold temperatures of recent days and nights probably stimulated the frogs into an out-of-character day-time chorus!
Female peepers, attracted to the calling of the males, enter the calling area and select the individual with whom they want to mate. The male then clasps himself onto the female’s back and remains there as the female return to the water source to deposit her eggs. The attached male prevents other males from mating with the female and insures that all of the female’s eggs will be fertilized by his sperm. The female can lay between 800 and 1000 brown-colored eggs either singly or in clusters. The eggs can be set afloat in the pond water, attached to submerged vegetation, deposited in the muddy bottoms of pools, or even put into fluid filled tree hollows or many other types of available micro-pools. Down along Roaring Run the eggs will probably accumulate in small pools around the rocks. Many will probably be eaten, though, by fish!
The eggs hatch in six to twelve days. The emerging larvae (the “tadpoles”) will typically remain in their aquatic form for ninety to one hundred days. This larval incubation period, however, can be as short as forty-five to sixty days depending upon weather conditions, time of egg deposition, and conditions in the tadpole’s pool. The tadpoles eat a wide variety of foods (including algae, dead vegetation, bacteria, fungi, zooplankton, flesh from animal carcasses, and even inorganic materials like sand). The tadpoles are, in turn, preyed upon by almost any organism that is larger than they are. Fish are especially significant tadpole predators in ponds and streams, but predaceous beetles, salamanders, and water snakes also readily consume the tadpoles
We listened to the peepers for several minutes before we detected a second sound in the frog chorus. It was a sharp “quacking” croak of the wood frog! The longer we listened the more clearly the wood frog calls stood out. For the past seven years we have gone down to Ohiopyle in March to look for wood frogs. We were just down there the week before, actually! How wonderful to hear them so close to home!
Everything is brown and gray along the trail. The forest floor is littered with dry leaves, and the gray tree trunks (mostly red maple, yellow poplar and beech) stand in dense copses, incredibly uniformly sized (8 to 10 inches dbh) all along the trail. These trees are secondary or maybe even tertiary recovery relics from the wholesale cutting back in the Nineteenth Century that was needed to generate the charcoal that powered the old iron furnace whose remains can be found on down the trail. There is also a stand of eastern hemlocks that may be a remnant of the hemlock forest that probably dominated this cool, wet ravine before the iron furnace was set up. Out in the surrounding acres of hardwood trees, occasionally a young hemlock can be found growing all by itself. These small trees are probably surprisingly old! If they last another three or four hundred years and actively drop their cones and seed around themselves, those hemlocks will be centers of ecological hemlock “crystals” that will reshape this forest back into a pure hemlock stand. All of the maples, beech and poplars that we see today, then, will then 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 I see other patches of green, too. Evergreen wood fern, Christmas fern and polyploidy fern up on the sandstone boulders have kept their chlorophyll all winter. Many of the rocks and some of the fallen logs and stumps also have mosses growing on them. Many of the moss mats have recently sent up sporophytes (they are so new that they are still green!). The knobby sporangia on the tips of the sporophyte 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.
Spring beauty is in bloom! Its delicate little white flowers are hard to see at first, but once your eyes adjust to their presence they light up the forest floor. Chickweed is also in flower. Cut-leaf toothwort (“pepper root”) plants are up and in leaf but not flowering yet, there are also many violets that have not yet set flower buds. Interestingly, the usual “first flower” of spring, coltsfoot, is no where to be seen. There is a south facing trail-cut just opposite the McCartney gas well at the top of the hill where the first coltsfoot is almost always seen. No hint of its yellow flowers today, though.
There are drainage ditches alongside the trail that are full of still water. Often these ditches have salamander and toad egg clusters in the spring. Today, though, the water is clear and there are no egg masses.
It is barely spring down on Rock Furnace Trail! All of the plant and animal signs of spring seem to be so much later this year than usual. Once we hit some warm weather, though, the pace of “spring-change” will be hard to keep up with!