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Protectors of Pine Oak Woods · Current
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Forest Restoration Forest
Restoration August 20, 2010
The Saturday of Protectors’ 170th consecutive Forest Restoration was certainly a good day to work in the woods; although sunny with temperatures in the sun reaching almost 90 by noon, it was at least 10 degrees cooler in the shade of the trees and there was no humidity to speak of - a welcome change from the weather we experienced last month. Five of us came out in an attempt to eradicate the last bit of English Ivy (Hedera helix) growing in the triangle between the White Trail and the Bluebelt pond adjacent to Meisner Road. We were almost successful - and success is rarely achieved when combating invasive plant species - but five of us were just too few to completely finish the job. So close... so close.... I don’t recall how long ago it was that we started on this Ivy patch. Dom Durso thinks it’s been five or six years since Dick Buegler decided to add this corner to our rotation of sites. The ivy then almost completely covered 3/4ths of the ground between the trail and the road, although spotty at the very road edge, and was working its way toward the stream that runs parallel to the Bluebelt pond. At first we began by cutting and pulling down as much ivy as possible from the trees. This accomplished four things: it reduced the wind and weight burden the trees had to bear, it relieved them of competing for sunlight with ivy in the canopy, it exposed previously damp and shaded bark making it less susceptible to mold and rot, and most importantly it prevented the ivy from producing seeds. (English Ivy must grow for several years before it can set seed, but it also must get to the sun. The ivy ground cover in the shade of the canopy will continue to spread vegetatively, but will rarely produce seeds.) In future sessions we concentrated on pulling up the ivy by the roots. English Ivy has relatively shallow roots and is normally easy to uproot, but it has been growing here for such a long time that the vines are intertwined, and any attempt to pull up just one is resisted by all the interlaced others. We usually had to untangle one piece of the ivy spaghetti at a time until enough had been unknotted that they no longer had mutual support. Then we could snake the remainder out, one or two strands at a time. In past sessions we concentrated on working our way steadily downhill from the trail, every now and then making a sweep uphill from the stream to prevent the ivy from getting closer to the water. Occasionally we’d start again from the edge of the trail to catch any new ivy sprouting from buried bits of root left behind. The tiny corner remaining, close to the intersection of Meisner and London, is probably one of the more difficult parts: here there is soil-covered rubble fill, small gullies and slopes, and a tangle of fallen branches that the ivy can grow through and under. Runoff from the road has created a shallow new gully, and strands of ivy have found their way to this new source of moisture. We stopped with only a few hundred square feet to go, so there will have to be another visit next year. Not to lead you astray, there is much more ivy close by; several hundred feet to the north another large patch if ivy intrudes into the woods, and there are other parts of the Greenbelt where ivy has a substantial foothold. This particular patch, however, I think we can call a success story. At the end of the session we picked up our weedhooks and returned to the cars by way of the trail entrance at London Road, stopping to admire a Jack-in-the-Pulpit Dom had noticed whose seed cluster was in a stage half-way between summer’s high-gloss green berries and fall’s brilliant red. Its growing season over, the leaves of the Jack have wilted leaving only the seed stalk standing, and that too soon will fall. At the trail we stopped to note that the American Basswoods (Tilia americana) we had planted there - four years ago I think - have been very successful. There is now a substantial little grove of half a dozen thriving saplings. We had planted a variety of trees and shrubs at the edge of the trail which was mostly loose fill, and of all of these the Basswood has done exceptionally well. It was disturbing, however, to note that local home-owners are still using the edge of the trail by the road to dump their yard debris. It’s rather shameful to say, but many home-owners think that it’s their right to dump grass clippings and unwanted landscape plants on the edge of any convenient vacant lot or woodland. There used to be a thick growth of Jewelweed between the trees and the trail, but the near-drought condition has seriously reduced their number, which hasn’t been helped by burial in piles of grass clippings. Before stowing our tools in the shed at High Rock, we paused to pass around a chunk of a bracket fungus that is called Artist’s Conk, (Ganoderma applanatum). This is a common wood decaying fungus that we occasionally find growing as brackets on fallen logs in our woods. It is a polypore, and the fertile surface that produces spores occurs in a layer of tiny round holes, or pores, on the underside of its shelf-like fruiting body. The pores of the Artist’s Conk are very small and white, and bruise dark if scratched or otherwise damaged, and so enable one to scratch a quite detailed drawing upon it. If the conk is dried, the pore surface is preserved and can be further protected by spraying with laquer or other artist’s fixative. Many Natural History Museums and Nature Centers have examples bearing elaborate, highly detailed scenes. One of our group tried a scratch sketch, and although her efforts didn’t quite reach the level of high art, they were none-the-less entertaining. After a quick trip to High Rock to return out tools, we set out to visit the Bluebelt pond - which since I don’t know the official name I’m going to call Meisner Pond - to begin our walk. At Meisner Pond we took advantage of an unlocked gate to visit the edge of the dam. The oncoming autumn was evident; the buds of New York Ironweed (Vernonia noveboracensis) have finally burst into flat-topped sprays of vivid purple, and here and there Woodland Sunflowers introduced spots of summer yellow to the almost monotonous green edge of the pond. The Blue Flag Iris (Iris versicolor), which for the most part had finished blooming by our previous restoration, now sport green, three-sided, lozenge-shaped seed capsules. Soon these will turn a striking brown and curl open at the tips to scatter the three stacks of thick, semi-circular seeds within. We made our way further up the side of the pond and, courtesy of the low water that our recent dry spell had produced, crossed over to a ridge usually islanded at the edge of the pond. What are usually inaccessible emergent plants were more exposed to view there (emergent is the term that botanists give to those plants that grow partially or completely submerged at the edge of the water and whose stems and leaves emerge from the surface). Long stalked, pear-shaped, seed pods of the Arrow Arum, a relative of the Jack-in-the-Pulpit, lay on the surface of the water beside arrow-shaped leaves and weirdly resembled the twisted necks of dead, green swans. Nearby another emergent displayed similar arrow-shaped leaves, but was in bloom with whorls of three white, three-petaled flowers which identified it as broad-leaved arrowhead (Sagittaria latifolia), which I called Duck Potato, a common name not favored by any of the field guides we carried. Duck Potato gets its name from small, starchy tubers it produces on its roots in the watery muck. Native Americans ate the tubers, and muskrats do so now, but paradoxically not ducks which for the most part cannot reach the roots. (Because they have a flavor that appeals to me, I am rather saddened that these old-fashioned regional common names sometimes fall from favor. I think there’s a loss in the attempt to whittle down and standardize the many common names locally born by plants and animals. For example the American Ornithologist’s Union which has “jurisdiction” over the naming of North American birds prefers Kestrel to Sparrow Hawk and Long-tailed Duck to Old Squaw. I like the old names better, but that’s a minority view.) Around the Arrow Arum grew sprays of Water Plantain (Altisma triviale) whose numerous three-petaled flowers would resemble those of Duck Potato if you could look at them with a magnifier. They rather gave the impression of Baby’s Breath accenting a green bouquet! Since we were “botanizing,” we looked about for more plants in bloom and found others with peculiar names; close by on shore were Square-stemmed Monkey-flowers (Mammals rigens) and Mad-dog Skullcaps (Scutellaria lateriflora). Floral gardeners would recognize Mad-dog Skullcap as a small-flowered lobelia, and indeed they are said to be one of our most common wild lobelias, growing customarily on shady, wet edges. The flowers were indeed tiny, only about 1/3 inch long, occurring in pairs on branched flowering stems, each plant no more than 18" tall; we probably wouldn’t even have noticed them if we had not been looking. Mad-dog Skullcap... w/url?sa=t&source=web&cd=1&ved=0CBsQFjAA&url=http%3A%2F%2Fwww.illinoiswildflowers.info%2Fwetland%2Fplants%2Fmd_skullcap.htm&ei=O_x0TKKsFoL7lwe93ZX9Bg&usg=AFQjCNHtROmrWbAV54AY-wIJ55GTcUJ_iQho names these things anyway?! The skullcap part is understandable, because the upper petal can be seen to form a rounded, dish-like dome that resembles a naked skull over the other parts of the flower, but the “mad-dog” part? Ok, a dog skull maybe, but where did the mad come from? A web search procured information from a commercial seed site that claimed early settlers used concoctions of this plant to treat rabies, without much success I’d guess, but there were no citations to verify the information. Other herbal medicine sites informed me that various native Americans throughout the country valued its medicinal properties. The plant probably does have affective properties that suggest it might be medicinal; it seems that few insects and mammals browse on the leaves because they contain bitter alkaloids. The Square-stemmed Monkey-flower also grows along moist shores. Like the Mad-dog Skullcap, it has square stems which are characteristic of flowers in the mint family . . . but the Monkey-flower has lately been removed to another family. (I’m sure that many of us would like to be able to move certain relatives to another family, but for most of us it’s not easy...) Taxonomists, the scientists whose speciality is grouping organisms to show their relationships and highlight similar characteristics, have lately been regrouping a number of plants as a result of having new tools such as DNA analysis. (If we study nature, we are urged to employ scientific names so that there is no misunderstanding about which organism we refer to. Because of recent DNA studies some organisms long thought to have been properly pigeonholed have been moved from one genus - the next largest “pigeonhole” in which species are sorted - to another. Some fungi have been moved two or three times in the past century, giving amateurs studying them much grief; none but serious mycophiles can keep up, and botanists are now struggling with the same problem. Writers currently try to use both scientific and common names as an aid to their readers when the “new” scientific name might be unfamiliar.) The irregular flowers of the Monkey-flower are larger than those of the Skullcap, and the lower center petal has a yellow patch back toward the flower’s throat. My Peterson field guide says the “lobed violet lips suggest a face” - a monkey face supposedly - but I’ve never seen the resemblance... not enough imagination I guess... Further down the trail a few Harvestmen, which as kids we called Daddy-long-legs and sometimes still do, picked their way over branches of spicebush hunting for smaller invertebrate prey that will try to kill with their poison fangs - don’t let them worry you; their fangs, called chelicerae, are too weak to piece human skin and they are much too worried about getting away from you. Look closely and you will see that they have four pairs of legs, so they are not insects, which have three pairs, but are in the same group as the spiders, the Arachnids, which have four. Harvestmen, however, form a group of their own called Opiliones (don’t worry, this will not be on the test), and are differentiated from the spiders by the structure of their bodies. Insect bodies are seen to be divided into three main sections: head, thorax, and abdomen. Spiders have two sections; their head and thorax are combined (and logically enough called a ‘cephalothorax’) and separated from their abdomen by a narrow waist. Opiliones have combined all three body parts and so look a bit like tiny loafs of bread on eight long legs. The most important difference between spiders and harvestmen, of course, is that spiders make silk and harvestmen don’t. Harvestmen, in fact, don’t even have silk glands, whereas all spiders do (even those spiders that don’t make webs deposit their eggs in a sack made from silk). Harvestmen seem to be everywhere now, but that’s just because they’ve become bigger and bolder since spring when they were hiding as tiny infants in the leaf debris, continually growing and molting until now they are large enough to attract our attention. Sometimes at this time of year you will see some adults moving about with what seem to be minute bright red balloons on their abdomens and close to where their legs attach. These aren’t party ornaments, they are tiny parasitic mites. As Jonathan Swift was paraphrased, “Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum.” No doubt a proper microscope would reveal that these mites carry their own burden of parasitic roundworms and other creatures - the mite’s own “lesser fleas.” We continued our walk along a loop in the bottomland formed by the White and the Red Trails. Jewelweed (Impatiens capensis), sometimes called Touch-me-not, which normally flourishes there in the wet areas was sparse and straggly with only a few dangling, orange, cornucopia-shaped blossoms - not much nectar to be found there to refuel migrating hummingbirds this year! No doubt the extended dry period has adversely affected them. I expected to see a few already in seed, but visible seed capsules were few and tiny. Perhaps now that there has been some substantial rain they will flourish again; they have a long blooming period and given a chance should continue to flower and seed for several more weeks. Jewelweed is an annual, grows anew from seed every year, so a drought year that limits seed production threatens to substantially reduce the number of plants that spring up the next growing season. No doubt though, there are still dormant seeds in the soil from previous years that will supplement next year’s crop. The seeds of annuals, as a rule, spread out their dormant period so that there will still be some viable seeds left to sprout following a series of bad seasons. For annuals, this would be a necessary survival strategy. Jewelweed gets its name when beads of rain and dew ball up on its waterproof leaves and gleam in the sun. It’s a favorite of wild plant foragers since it has the reputation of being able to relieve poison ivy inflamation with its sap. I have read that an application of its sap is also good for relieving the pain of contact with stinging nettle, but whenever I’ve inadvertently brushed through nettle, there hasn’t been any touch-me-not in sight. The most captivating thing about Jewelweed is its exploding seed pods. One of the best nature walk “tricks” is to have youngsters try pick fat, ripe pods and observe their reaction when the pods explode in their hand. If you haven’t experienced this give it a try; gently grasp a fat pod with its long ends between thumb and forefinger and give it a slight squeeze. The ends of the pod will abruptly curl back and fling the enclosed seeds some distance away. Exploding seed pods have always intrigued me; what a good way to spread the next generation in all directions insuring that some seeds will find new patches of fertile soil and that the new offspring won’t have to compete with each other for sun because they are all trying to grow in the same spot where the seeds fell. There must be many other seed plants that use this technique, I thought, but it seems that here in the northeast there are relatively few plants that make use of “exploding” pods; the Impatiens such as Jewelweed, some members of the pea family such as the Oriental Wisteria we try to remove from our woodlands, and that strange shrub that flowers in late fall or early winter, the Witch Hazel. (If you know of others, let me know. I’m curious.) With the exception of the Impatiens such as Jewelweed, all of these plants use tension in the walls of the pods created by drying to fling their seeds about. Unlike the others, Jewelweed pods explode while they are still green, so it seems likely that turgor (fluid pressure) built up in the pod walls probably plays a part in splitting the pod open. There is another fluid mechanism employed by a European squirting cucumber which acts like a bottle rocket. When the seeds are ripe, pressure builds up inside the cucumber until the stem can no longer hold it attached. The stem breaks and the cucumber shoots away with a stream of liquid and seed “exhaust” streaming out behind! This would be some sight to see, unfortunately none of our seed plants do this (if you’d like, paste the following link into your browser for a slow motion look http://www.thoughtequity.com/video/clip/1B0725_0011.do - there are also amusing you-tube videos of young people getting squirted by the cucumbers they have set off, but you’ll have to search these out for yourself). When fluid tension in the Jewelweed pod has built enough, the pod can no longer hold together and the pod abruptly curls open like a peeled banana flinging the seeds inside up to six feet away. Those legumes which throw their seed work on a drying principle. The pods of the wisteria are constructed as two long layers, or valves, with a seed layer between. As the valves dry, their tissues warp and try to twist in opposite directions. When the pod can no longer sustain the strain, the valves split and throw out the seeds, sometimes with considerable force. You might observe this by bringing some almost mature wisteria pods into the house and letting them dry; sooner or later there will be a sharp “pop” or “crack” followed by the rattle of seeds pinging off the wall. (The seeds can fly 50 feet and more, so perhaps goggles are advisable!) Witch hazel (Hamamelis virginiana), a shrub of moist woodlands recognizable by its wavy-edged, blunt-ended leaves, produces spidery, four-petaled yellow flowers late in the year, paradoxically just when it is losing its leaves! If the flowers are pollinated, they produce a green, two-chambered seed pod, each chamber containing a single seed. The pods mature the following year, drying out and becoming brown by the end of the next summer. The result is that the pods of last year have become mature when the flowers of this year are blooming and both the mature seed pods and the new blossoms are present on the shrub at the same time. As the pods dry tension builds in their walls until suddenly they split from the tip, flipping the seeds some ten to twenty feet away. You could collect a few branches with pods in late summer and bring them inside to dry. If you’re fortunate you may be present when they fire off their seeds, but as with the wisteria you’re more likely to hear them than see them fly. Whereas our locale doesn’t seem to sport many plants with “ballistic” seeds, there are other plant-like things that use similar mechanisms. We might not have Squirting Cucumbers, but in the kingdom of fungi we have several organisms that use hydraulic pressure to launch their spores. One such is a tiny fungus that grows on cow pies - our euphemism for what comes out the other end when a cow dines - called Pilobolus crystallinus. The genus name Pilobolus derives from the Greek and somewhat literally translates as “hat thrower”. Once this fungus has grown sufficiently on its native pat of dung, it develops tiny stalked fruiting bodies that resemble stacks of minute crystal beads, each stack bearing a large crystal bead on top wearing a tiny black beret. The “beret” is the sporangium that contains the spores. You’ll need a microscope or good hand lens to see these. When the spores are ripe, pressure builds up in the large “beads” until they literally blow their tops, shooting the black spore containers up to several feet away. A time-lapse video of these fungi growing and sporulating can be found at: http://www.youtube.com/watch?v=9CRNmde0WUc, and one in which you can actually see the spores shooting away is: http://www.youtube.com/watch?v=TrKJAojmB1Y For being a “simple fungus,” this operation is rather sophisticated. Before it “blows its top,” the fruiting body bends toward the light. If the fungi are grown in the laboratory, this response can be viewed by lighting them from the side. Discharging the spores toward the light helps insure that they are not deposited under some shady bush where cows would not be likely to graze. More important, though, is that the spores are shot some distance away. Cattle generally don’t graze where forage grows through fresh dung - a strategy that helps them avoid ingesting excreted parasites - so it is in the interest of the fungi to shoot its spores out of the ‘blighted area’ to fresh grass where they might be eaten by cows, pass through the cow’s digestive tracts, and begin the cycle anew in fresh cow pies. There are other “explosive” fungi, such as the Artillery Fungus in the genus Sphaerobolus (in this case they’d be “sphere throwers”) that grow on wood mulch and annoy homeowners by speckling their siding with dark-colored spore cases, but I think an account of the Hat Thrower is enough for now. One final comment: I wrote before about discovering this summer that Viburnum Leaf Beetles have finally made their way to Staten Island and are beginning to damage Arrowwood Viburnum in our woodlands. Keeping an eye out, I found that they are already widely dispersed. I have seen them in southwest LaTourette, the Egbertville Ravine, and in High Rock Park itself. The beetles do fly, and they have made their way south from the site of their introduction in Canada very quickly. No doubt now they can be found all over Staten Island, and there seems to be no way to eliminate them from our woods. Local homeowners may be able to employ insecticides to protect landscape specimens of susceptible viburnum species, but such treatment is not feasible in natural wooded landscapes. The beetles are here, and we will have to wait and see what kind of equilibrium will develop between the beetles and the viburnums they infest. Several insects such as the Ladybird Beetle and their larvae prey upon them, and it may be that these natural controls will limit Viburnum damage. I suspect, however, that we may expect a substantial alteration in the composition of the understory shrubs in our woodlands. If it’s any consolation, Viburnum Leaf Beetle eggs require a substantial cold period before they will hatch - this prevents a warm spell in winter from causing the eggs to hatch prematurely - so there will be a limit to far south they can go. Unfortunately, that will be further south than Staten Island.
Beetle larvae, LaTourette
Beetles, High Rock Park
Beetle egg deposit, Egbertville Ravine
DfR 8-28-2010 |
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