|
Protectors of Pine Oak Woods · Current
Issues · Kreischer Hill Rare Plant Community |
|
Forest Restoration Forest Restoration June 19, 2010 The weather for Protector’s 168th Forest Restoration was forecast to be warm and humid, uncomfortable conditions for working in the woods; Chuck Perry was away for the week, so only four regulars braved the heat and poison ivy. As was often the case, the weather turned out better than the forecast, and it was actually comfortable where we were working along the White Trail between Elanor Street and Nevada Avenue. Our focus was the large vines of Oriental Bittersweet (Celastus orbicularis) that have climbed high into the trees alongside the trail. In that place portions of the trail impart an almost rainforest appearance with macramed ropes of vines rising into the canopy. Up on top their leafy vines spread out under the sun, forty feet and more above the ground, shading out large portions of the trees that support them, flowering and producing copious berries to be spread by the birds in the fall. Down below the thick vines have pulled many saplings to the ground, bending them over like gigantic bows. Woody twining vines like the bittersweet have no curly tendrils, aerial roots or suckers with which to attach themselves to their supports. They climb by twining up around the stems of other plants. (If you’re interested, there are a few web sites which show vines twining: http://sciencetrack.blogspot.com/2007/07/twining-motion-of-vines.html has a good U-Tube illustration of Morning Glories, & if you’re like me, while you’re there you’ll probably be unable to resist following their link to “worm charming”) Studies have shown that when the support is too thick, the vines can’t complete their curl around a stem. If I recall correctly the magic number for a diameter too big to curl around is about 3-1/2 to 4 inches, but no doubt the diameter is different for the different woody vines. Because of this some say that if saplings can be kept vine-free until they have grown large, the vines can’t strangle them and they will probably survive. Unfortunately, that is only partly true. The vines can harm trees in other ways, for example, by growing into a tree’s crown, adding weight and wind load for the tree to support and by competing with the leaves of the tree for light. Here we see saplings not only being strangled, but pulled down as well. In addition, the smothered saplings can be used as a scaffold with which the vines can reach low-hanging branches of the taller trees; once a low-hanging branch is reached, the ascending vines shoot into the tops. (I had often wondered about these woody vines disappearing into the leaves some twenty feet above like tropical lianas. Just how did they get there? Did all of them spring into the trees from the tops of shrubs below? Where then are the remains of the shrubs and saplings they grew upon? In some cases one can see the remnants, in others the vines hang unimpeded to the ground. Is it possible that some of these high, free-hanging vines have dropped back down to the ground below and rooted again? I know that bittersweet can grow vegetatively by rooting from stems both above ground and underground, but I have nowhere read that they can root from the very tips of hanging vines. Perhaps someone will enlighten me.) We did cut small vines away to rescue young saplings; several were bowed over and had grown thick in their arched posture so that they will never reach the sky like a proper tree, but other younger trees did spring back somewhat and we had better hopes for these. Our main work, however, was to attack the thick ascending vines with loppers, cutting them as low as possible to the ground and again as high as we could reach above. This is necessary to create a large gap so that new shoots of bittersweet and Japanese Honeysuckle (Lonicera japonica\x) can’t use the cut but still hanging vines as a trellis. Vines ½ to 1-1/2 inches in diameter required that we use loppers instead of pruning shears, but many vines, especially those further off the trail, were up to 3" in diameter and had to be cut with a saw. At the end of the work period we returned out tools to the shed at High Rock Park in which the Department of Parks has allowed us to store our tools. Following Dick Buegler’s move to Pennsylvania, Chuck Perry stored our tools in his basement, and brought an appropriate selection to each work session. Last week, during Chuck’s absence, Sandra Mechanic transferred most of them to High Rock; there they will be more centrally located although we will have to collect them from High Rock for each Restoration. Dom Durso provided water for us and Elaine Croteau brought the usual refreshments (although she is getting a little peeved that our meager number of participants require that she take cookies back home). Following the restoration we took a two-part walk, first northwest on the unmarked trail paralleling Rockland Avenue to the junction of the Red and Blue Trails, and back, then a second part following the White Trail west up the hill by the Nature Center, then returning on the Red to the unmarked Hyerdahl Hill trail to the White Trail and the cross-over in Buck’s Hollow and back to our starting point by the co-joined Yellow and Red (We have a choice of lots of color in the Greenbelt; this time we didn’t even set foot on the Blue or Green!). I should mention that the trail down from the Hyerdahl ruins isn’t precisely unmarked; there are a few faded orange blazes that survive from when Bruce Kershner wrote Secret Places of Staten Island, and the trail is shown as an unblazed path on the Greenbelt Trail Map. At this time the trail is difficult to traverse. Overgrown, eroded in places and blocked by numerous small fallen trees, it will eventually become impassible without some intervention. The cycle of seasons has turned again to what I call the “green season” in the woods, when the flush of colorful spring flowers has passed and most of the summer flowers are yet in bud; along the shadier parts of the trail we saw mostly Avens (Geum canadense) and Black Snakeroot (Sanicula marilandica), both having inconspicuous white flowers. An alien plant called Nipplewort (Lapsana communis) with a branching cluster of small dandelion-like flowers caught our attention simply because they were yellow! On the edges of the Bluebelt pond by Meisner Road we thought to see spots of color of Blue Flag (Iris versicolor) lining the banks, and the vibrant orange blossoms of the alien Wild Daylily (Hemerocallis fulva), but the time of Blue Flag blooming has past, and they were present only as flat fans of narrow green blades. By the edge of the dam there were Daylilies and Common Milkweed (Asclepias syriaca) with a few flower-heads in bloom being prowled about by bumblebees and wasps. Very soon more of the Milkweed flower-heads will have their blossoms open and these will be visited by Monarch butterflies (Danaus plexippus) making their summer journey up the East Coast generation by generation from their winter hibernaculum in Mexico. They will arrive here in early July, mate, and their yellow, black and white caterpillars will appear on the Milkweed soon after. (Every time I write up these accounts I learn things I hadn’t known before. For instance, did you know you can easily recognize the male versus the female Monarch by the presence of a small spot on the vein of the male’s rear wing? This spot is a gland called an androconium, covered with scales that produce pheromones to attract the female butterflies . . . certainly good quiz-show trivia!) These striking caterpillars with pairs of black horns on each end have small need for protective coloration since they become distasteful from consuming the bitter glycoside latex produced by the Milkweed, and most birds learn to leave them alone. The area of the dam has been a good place to observe butterflies in July, but you’ll want sunscreen and a hat and close-focusing binoculars if you have access to them. Unfortunately this spot has lost some of its former attractiveness to butterflies because shrubs and trees have grown larger and shading and crowding out parts of what was a long flowered border. Milkweed is an interesting plant for all seasons, flowering through the hot summer months in clusters of up to a hundred or so blossoms, growing warty green seed pods in late summer, and distributing clouds of seeds in the fall when the seed pods split open down one side and release their serried ranks of seeds that float away on downy parachutes. In winter the distinctive silhouettes of their stalks add an accent to the landscape and the hanging husks of their pods resemble gigantic, brown, dangling commas. Close up, the flowers are striking, complicated geometrical constructions: five reflexed greenish sepals crowned by a hood of five waxy, short, scoop-shaped petals with horns that curve toward the center of the flower. Unlike most other plants the milkweed flower doesn’t hold its pollen aloft on wispy anthers so that it will brush off on foraging insects and be carried away to another receptive plant. The pollen of the milkweed flower is glued to the surface of strangely shaped structures that are hidden in the center of the flower. These structures are pairs of small orangish disks covered with pollen and connected by a thin strap with a thickened center that somewhat resemble pairs of old-fashioned earmuffs. If pollination is to be successful, a foraging insect must get its leg caught in one of the small slots between the petals and get tangled up with a pollinarium, which sticks to the leg and is pulled free when the insect yanks its leg loose. Then the insect must get tangled up again with another flower so that the pollinarium drops off on that flower’s female organ. That’s a rather complicated process, and because of that complexity successful pollination doesn’t occur often, but apparently often enough to perpetuate the species. Each pod that you see on a milkweed in the fall is the result of a pollinarium being transferred to a single flower in the cluster, and you will note bunches of unfertilized, dried flowers hanging next to the pod. In the fruiting season many milkweeds show no pods at all, and rare is the milkweed that has three or more. This summer I have been taking part in a citizen science project called the Great Pollinator Project, a study organized by the American Museum of Natural History and the Greenbelt Native Plant Center which attempts to get some sort of handle on the status of bees in the NYC area. The recent outbreak of Colony Collapse Disorder, a still not well understood malady that has decimated commercial honeybee hives across the US, brought about a realization that no one has any idea about the status of native bees (our common honeybee is not a native; it originated in Africa and was imported to us from Europe). In an attempt to generate a baseline about the types and numbers of bees in the NYC areas, the Great Pollinator Project enlists volunteers to observe and file reports about bee pollinators. In the past two weeks I spent an hour watching two milkweed plants with binoculars and noting what kind of bees visited them and how often. Although many insects visited the milkweeds in that hour, I saw only one, some type of fly, carrying a pollinarium. The bees, mostly larger bumblebees, seemed too strong to get tangled in the slots and adept at avoiding the pollinaria. One wonders what possible advantage such a difficult pollination process might confer upon these plants. (A web site with some excellent photos by a Canadian microscopist is: www.microscopy-uk.org/mag/artfeb05/bjmilkweed.html) We continued on the trail by the Meisner Bluebelt pond and exercised our rudimentary knowledge of ferns identifying Cinnamon Fern (Osmunda cinnamomea) by the vase shape of its large fronds and the cinnamon-colored “fur” on its stems. Because there had not been a recent rain we could still run our fingers down the stem of the fronds to collect a wad of reddish-brown felt. We also identified Royal Fern (Osmunda regalis) by its pinnate leaves which resemble those of the Locust tree. Like Cinnamon Fern it is a denizen of moist places, and both of these ferns were planted in this area by the Department of Environmental Protection when the retention pond was graded and deepened. Before heavy equipment moved in, the DEP removed many of the native plants and stored them in pots to be replanted later. A few years ago the large collection of potted plants in the shade at the northern end of the pond made a strange sight when one walked by on the White Trail, and it is possible that the particular ferns we examined may have been among them. The few Royal Ferns, however, seem to be slowly but steadily shaded out by the Cinnamon Fern around it. In the peaceful cool shade beside the pond the vegetable struggle for light still goes on. Further on the trail there were a few Rusulla mushrooms showing muted red spots on the ground. Russulas are brittle, gilled mushrooms that come in a variety of red and lavender colors depending on the species, and are very common in our woods. A few are a mottled, muted green color, and are said to be good eating by those that have the experience to recognize them (& I can’t emphasize enough that mushrooms should NEVER be eaten unless one is absolutely 100% sure of their identity and edibility). Some rich, velvety, reddish-brown caps half buried in the leaves turned out to be Milkcaps, the common name given to a group of mushrooms that have a latex-rich sap. If you bruise or cut the gills of these mushrooms when they are fresh the latex will pour out, white or creamy, sometimes changing color on exposure to the air, again depending on the species. Mycophiles (mushroom lovers) call it some lactarius, after the name of their genus (you might remember this by thinking that these mushrooms lactate!). These particular mushrooms, given their outward appearance, whitish latex and widely spaced gills may have been Lactarius hygrophoroides, although my field guides say these particular mushrooms have solid stems and the one I collected the trail was hollow. Lots of insects and slugs feast on fungi, however, and my specimen may have suffered this way. (Whenever we talk about mushrooms, a lot of Latin and Greek are usually involved. Mycologists use “scientific” names instead of common names so that no confusion arises about what they are discussing. Mushrooms didn’t come to colonial Americans with common names attached, and for the most part we don’t know the terms used by the various indigenous American Indians. European settlers imported common names for mushrooms that had a similar appearance to those they knew in Europe, but the English for some reason entertained very few common names for their mushrooms. Gary Larson, author of the popular Audubon field guide to North American mushrooms was compelled to provide common names for the mushrooms described in that book, but had to invent many of them. His choice of names often reflected some part of the botanical Latin nomenclature used by the professionals. For instance, a particular mushroom with reddish bands around the stalk called Cortinarius armillatus was named the Bracelet Cort - armillatus being a Latin adjective for wearing bracelets or collars.) Just before the White Trail branched away one of us noticed a knobby dark-brown growth on the stem of a young oak and being familiar with the common Black Knot fungus that attacks Wild Black Cherry trees wondered if this growth was similar. Similar yes, identical no. The knobby, hard, pockmarked thickening on the Oak was the Gouty Oak Gall, the result not of a fungal infection but the work of a small wasp. The female wasp had laid her eggs in the tissue of the tree, and the tree responded to the resulting irritation by growing around the developing larvae, unintentionally both nourishing and protecting them. Probably every plant we passed by on the trail bore one or more types of gall, and each of these galls had its own specific cause, usually - but not always - an insect of some kind. Oaks are especially susceptible to galls, and Ephraim Porter Felt in his classic study of native galls, Plant Gall and Gall Makers, estimated that Oaks host more than 600 different types - and his estimate is probably low. A striking Oak gall that is often encountered on higher, drier trails is the large, brown Oak Apple Gall which grows to the size of a ping-pong ball on oak leaves. (Oak Apple Gall is a kind of generic name for these spherical galls which come in several sizes and grow in different locations on the leaves; they are, of course, actually all different types of galls and are created by different species of wasps.) If you should cut open a green one, you will find it full of radiating white vegetable filaments leading to a central chamber inhabited by the wasp larvae. The structure looks vaguely like some kind of vegetable shock-absorbing suspension. In the fall this gall is brown and papery, the grub long since having metamorphosed and disappeared; the gall however, full of oak tannins, is slow to decay and can be found throughout the winter. Oaks are high in tannins and, in former times, tannin derived from Oak bark was used to tan leather, preserving it and making it pliable and tough. The tannins in Oak galls were used as well, mixed in solution with iron sulphate to create a purple-black writing ink which was used from the middle ages into the nineteenth century. Once available, durable synthetic inks then replaced gall inks, which tend to fade over time, and now gall inks are used only by historical enthusiasts and, perhaps, document forgers. Another insect produced gall that attracts notice on walks through the woods is found on the leaves of the Witch Hazel. The Witch Hazel Cone Gall has the appearance of tiny yellow or red-yellow rhinoceros horns (there’s a curious juxtaposition: tiny and rhinoceros). Witch Hazel almost always has a few of these galls somewhere, and sometimes they can be quite numerous. A large infestation must cost the trees a lot of energy, but they seem to survive. These galls don’t harbor wasp larvae, but instead house quantities of tiny plant lice or aphids which have mouth parts adapted for piercing and sucking the sap from their host plants. If you were to cut one open now, you will notice that the cones have a tiny hole on the bottom of the leaf and that they have been abandoned. None-the-less they will linger until the leaves drop in the Fall. When I cut a few open just a few weeks ago, they seemed to be full of speckled frass (if you’ve got kids along, that’s caterpillar poop to them!), but a hand lens revealed that the specks moved and were actually tiny four-winged aphids preparing to make their exit. Ephraim Felt, my source for gall information, says that the Witch Hazel Cone Gall insects have an unusual life-style; that they begin the year as a generation of aphids feeding on Witch Hazel and conclude as a generation of insects that feed on the underside of Birch leaves (using two different hosts sequentially is unusual but not entirely uncommon with gall insects). The aphids lay their eggs on Witch Hazel twigs in the fall, and in spring wingless hatchlings begin to feed on the new leaves which react by creating the conical structures. Each cone contains a single aphid which asexually produces the many winged offspring that I found when I cut open the cone. (This type of reproduction by unfertilized females is called “parthenogenic”) In early summer, these winged offspring emerge from the cones and fly to Birches, where they feed and, still asexually, produce several more generations of aphids. In the fall they fly back to the Witch Hazel and produce a new wingless generation of aphids, this time both males and females, which mate and produce the eggs that overwinter to become the spring wingless generation. Now wasn’t that simple! When you think about it, these are very specialized insects indeed, like all parasites very fine-tuned to fit a narrow niche in nature’s web. There is a considerable advantage to such specialization; these creatures have such fine-honed tools that they cause their food to create homes for them! But what they gain by specializing, they lose in adaptability. If something should happen to either the Birch or Witch Hazel, these insects would be doomed, unlike more generalist species that can satisfy their appetites on different plants.
But back to the trail. Our second trip, this time toward Hyerdahl Hill, rewarded us with four more ferns, among them two ferns that grow as stalks with three-part fronds. One of the three-leaved ferns was a rattlesnake fern (Botrychium virginianum) which we don’t often see, but is almost abundant in the shade along White Trail. These we recognized because some had recently produced spores and had a fertile stalk sticking up like a short flag above its three, horizontal blades. (Supposedly the fern got its name because the early appearance of the fertile frond resembled the rattle of a rattlesnake tail, but I haven’t recognized it at that stage. Most ferns, reproducing by means of spores at this stage of their life cycle, develop small dot-like spore cases called sporangia on the undersides of their leaves. Some, however, like the Rattlesnake Fern grow a special stalk for the task. Last month we would have seen lots of these on the Cinnamon Fern, sticking straight up like small cinnamon colored cattails.) On the drier slope we encountered colonies of Bracken (Pteridium aquilinum). Bracken, or Brake, is another common, durable fern with three pinnate leaves fanning out horizontally from a single stalk. It occurs all across the United States - in fact all across the world in our latitude. It managers well in both sun and shade, and seems able to survive in all but the most wet environments. Rooting deeply, it is sometimes an opportunist, springing up quickly after a fire and shading out its competitors. This is probably what has happened on Hyerdahl Hill, a site of several fires in former years, where Bracken extensively lines the trail. The species name of the fern, aquilinum, refers to the appearance of the young fern when it first breaks through the earth as a coiled “fiddlehead” or crosier. Because of the fern’s three fronds, the fiddlehead uncurls as three-parted coil, and when uncoiling looks much like the talons of a bird - thus the Latin word for eagle in the species name. Many wild food foragers eat fern fiddleheads, but there is evidence that some ferns are not very good to eat, even poisonous, especially if eaten uncooked. The Peterson guide, Edible Wild Plants, lists Bracken as an edible, but with caution. Those who raise cattle, especially horses, take care that Bracken isn’t available in their pastures and doesn’t contaminate their hay; it contains an enzyme that destroys the essential vitamin B1, and can be fatal to untreated animals. Because of a general fascination with things that bite, sting, irritate, etc., on our return down the hill we looked for the very poisonous Water Hemlock (Cicuta maculata) which commonly has been found on the very wet side of the trail just below the Hyderdahl Hill turn-off, but were surprised to find only a few small plants not quite in bloom. Water Hemlock is in the Parsley family, the same family that contains carrots, parsley and many other edible vegetables, and blooms in a flat cluster of tiny white blossoms much like those of the familiar Queen Ann’s Lace (which is also in the Parsley family). The Water Hemlock, however, is definitely not in the edible category (although perhaps it could be considered to be edible just once as a “last meal”). Water Hemlock is a plant of wet meadows, and the trail in that place seemed just as wet as usual, so a change of hydrology probably wasn’t the cause of its absence. However, shrubs and small trees, especially Birch and Sweet Gums have been growing up along the trail, perhaps depriving the Water Hemlocks of light. A few were still there, however, and to make up for their reduced numbers had spread further east and also jumped across the trail. Well, that’s enough for this session, but for a postscript. At the time of our wildflower planting at Great Kills I expressed shock at the amount of erosion of the beach on the Raritan Bay side of the peninsula and remarked that the Bank Swallows which nested there in holes in the bank might find that erosion has made their nests no longer safe. I was pleased two weeks ago to see an account in the New York Bird report by Ben Cacase in which he reported seeing over 50 bank swallows hawking there about the shore. The birds, for now, are still there, and may still nest successfully. DfR June, 2010
|
©2004 PPOW