June Heavy Rains Affect Euclid Stream

The heavy rains and winds in late June caused some trees to be uprooted and branches to fall in the stream.

The new outfall construction just completed for the stream between the bamboo grove and the wetlands held up, although the straw and mesh was swept away in some areas.

Post-storm damage - first culvert
The first culvert downstream of the bamboo grove after the 7/28/2015 thunderstorm.

Here is a link to more pictures and descriptions.

Eastern Cottonwood: the Rarest Tree in Parkwood

Below is an article I wrote for the April issue of the Parkwood Inside/Out.

The rarest tree in Parkwood

The big tree between the Parkwood Athletic Association field and the Masjid Ibad Ar-Rahman mosque might seem unremarkable, the quintessential tree, but it is the only Eastern or Carolina cottonwood I know of in Parkwood. Until recently it was the only one I knew of anywhere, but a year or two ago I was at the intersection of 54 and 55 and realized that the tall tree beside a stream between Walgreens and McDonalds is a cottonwood, and I saw a cottonwood of some kind at the Rollingview area of Falls Lake. River Dave once told me there are some along the Eno River and closer afield at New Hope Creek. Next to Parkwood’s cottonwood there used to be a pile of ballfield gravel, which resembles rocks along the Eno, so I wondered if the cottonwood might have come with a load of gravel, but since there is another arone around, maybe it came from this area after all.

Cottonwoods (Populus deltoides) are real poplars (“tulip poplars” are in the magnolia family) and resemble famous relatives like quaking aspens. The name poplar might come from a Latin phrase, arbor populi, the people’s tree, and the deltoides probably refers to the leaf shape. Eastern cottonwoods have large, spade-shaped leaves ending in a long point and with hook-shaped serrated edges. The leaf petioles are long and compressed, and there are glands at the leaf end. With these long stems, the thick leaves flap in a breeze, making a lot of noise. The yellowish twigs have a lumpy profile and have a squarish cross-section where there is a lot of growth. The terminal buds are covered by 6-7 scales and are supposed to be sticky or resinous, but not fragrant. Cottonwood leaves fall early in the season and without much color. Cottonwoods put on height quickly, as much as 13’ their first year, getting about 100’ tall (but higher in the West), sometimes after only 15 years, and develop an ever spreading form similar to broccoli, as can be seen in Parkwood. Our cottonwood has a stout trunk with strong branches starting near the ground and sweeping around, ending in twigs with an upward turn like claws. Cottonwoods have thick bark, but young trees are not very fire-tolerant, one factor limiting where they could grow out on the prairies. As with many fast-growing trees, cottonwoods don’t live very long, only about a century.

Other poplars grow in NC, including swamp cottonwoods (P. heterophylla), but I think our tree is an Eastern cottonwood. The only other poplars I know of in Durham are the very columnar Lombardy poplars, European ornamentals planted in yards, and white poplars, naturalized European trees which have an overall white appearance and form thickets, such as the one behind the former Triangle Nursery.

Long, wind-pollinated catkins (thus the name necklace poplar) emerged on Parkwood’s cottonwood in early March, while the leaves were still in large, conical buds. Each tree produces only one sex of flowers. On female trees small cottony seeds mature later in the spring, and fill the air. Wind dispersal allows cottonwoods to find rare open ground, such as bare banks of streams. The seeds have to drift to suitable ground fast, because they don’t remain viable very long.

In tree-rich Durham, cottonwoods are just another deciduous tree, but they could be called a Laura Ingalls Wilder tree, and were valued out on the prairies, where they were one of the few large trees, usually growing near water. The outer sapwood is wide, whitish, and lightweight, while the heartwood is dark brown. Cottonwood is easy to carve, but inflexible and warps a lot when drying, so it is mainly used for crates, plywood, excelsior (shredded wood, like the mulch on the path to the Hidden Playground), matches, and paper pulp. Indians in the Midwest used cottonwood for poles and started fires with the roots, and reportedly teepees relate to the shape of cottonwood leaves and children played with various tree parts. Cottonwoods are planted as windbreaks and to reclaim mines.

Deer, beavers, rabbits, and mice chew on the twigs and livestock can eat saplings if hay runs out. One guide says tea of the inner bark was used as a “female tonic” and to relieve scurvy, and cottonwoods produce aspirinlike salicin. Purple finches and other birds and squirrels eat the buds and catkins. Bees sometimes harvest the pollen, though the trees don’t rely on animals for pollination. Mourning cloak and red admiral caterpillars might eat the leaves, but around here they have many other choices, so cottonwoods seem to have few herbivores. Cottonwoods frequently develop internal rot, creating cavities for owls and squirrels.

To find out about the black locusts blooming at Parkwood Lake Dam this month and the honeylocusts on the Tobacco Trail, check out my article in the April issue of the Chatham County Line) newspaper.

My article in the May issue covers catalpa trees, such as the southern catalpa on Revere Road and others blooming in a few weeks.

Durham Creek Week Kickoff features Northeast Creek Critters and Puppet Theater

The 2015 Creek Week Kickoff at Durham Central Park on March 21, 2015 saw the creek critters from Northeast Creek march in the parade with people from the other watersheds in Durham County.

One of the highlights of the event was the Northeast Creek Critter Puppet Theater featuring Woodrow the beaver and Clyde the raccoon and puppeteers Barry Archer and John Apel.

The elms are flowering

This is an article I wrote for the February issue of the Parkwood Inside/Out. We are planning trash cleanups on March 28th and a hike, and will be participating in the costume parade downtown on March 21st and other events for Durham Creek Week 2015. Check this website for announcements and all events will also be posted at:

http://keepdurhambeautiful.org/our-events/durham-creek-week-events/

Parkwood’s elms are blooming

Red maples dotting the still bare landscape with blots of crimson are one of the first signs that spring is here, but elms are among the first trees to flower. These prominent trees might be less appreciated because an elm in flower is stormy grey or lime green. Winged elms are the most common species, especially in central Parkwood, but there are slippery elms along the streams and probably American elms, and there are scattered Eurasian ornamentals. The most prominent and beautiful elm I know of in the area is the classically fountain-shaped tree on Highway 54, across from . Because its limbs are all high above the ground, it is hard to identify the species.

Elms, especially American elms, are beloved for the fountain or vaselike shape of mature trees, and there is a graceful symmetry to elms generally. Their leaves and branches alternate, creating an airy lattice effect. The straight veins in their oval leaves, double toothed like a pruning saw, are straight and parallel, but elms also have a very unsymmetric feature – the leaf bases are lopsided, especially in American and slippery elms. Elms have thin, elegant branches, strengthened by very tough wood, and the bark of some species can be twisted into rope. They produce wind pollinated bisexual flowers in early spring, developing into small seeds with a circular flange that drift with the wind several weeks later. The elms generally like moist soil, but winged elms seem to grow in drier soil as well.

The massive, spreading elm in front of Carrboro’s Town Hall could be an American elm (it is big enough for a plaque, yet nothing identifies the species), and I think there are labelled American elms in the Coker Arboretum at UNC. American or white elms are around, but are less common after the arrival of Dutch Elm Disease, a fungus that came to the US around 1930, and is spread by introduced and native beetles that bore in elms. Many elms have been killed, especially American elms, but this seems to be a little less catastrophic than the introduction of chestnut blight and emerald ash borer beetles, and the disease can be managed. American elms are large trees with furrowed bark, brownish leaf buds, and their leaves and stems aren’t very hairy, or less so than slippery elms. Their seeds have some hairiness, while the seeds of slippery elms lack hairs. Both American and slippery elms have large, sandpaperlike leaves, but American elms have greenish flowers, unlike slippery elms. Because their wood is so strong and resistant to splitting, and grips screws tightly, American elms have been used to make things like sports equipment, boats, flooring, crates, and kitchen cutting blocks. Many were planted for landscaping in the northeast, though they grow throughout the eastern USA. In A Natural History of Trees, botanist and nature writer Donald Culross Peattie wrote “If you want to be recalled for something that you do, you will be well advised to do it under an [American] Elm – a great Elm, for such a tree outlives the generations of men; the burning issues of today are the ashes of tomorrow, but a noble Elm is a verity that does not change with time. And although Elms too are mortal, great ones are remembered as long after they are gone as are great men.”

Slippery elms are similar to American elms, but smaller and less vaselike. They have been called red elms, having hairy, reddish leaf buds and reddish flowers, as well as hairy twigs. Their inner bark is slippery and becomes mucouslike when chewed. This inner bark was used to make tea and flour and was used for a variety of internal and external problems and still has an FDA approved medical use. American elm bark was used medicinally by Native American groups.

Winged elms are named for the cork flanges that line their twigs to varying degrees. Sweetgums usually aren’t as winged as elms and their leaves are very different. Winged elms leaves are smaller, smoother, and more symmetrical than those of other elms, and large trees have light brown bark. I think these are the first elms to flower, with brownish flowers that turn into silvery, hairy seeds. As with most trees, winged elms grow a lot when they first leaf out in spring, delicately etched leaves surging forth from the twig tips at a fast clip. The tiny, silky looking new leaves hang as if limp, but are actually strangely stiff. Snow, ice, and maybe hurricanes smashed many of the spindly young loblollies behind the Fire Station around 2002, leaving winged elms, ash, and a few surviving pines as the dominant tall trees, to be replaced themselves by oaks, hickories, and beech in coming decades.

Many animals chew on elm branches, leaves, and seeds, including opossums, rabbits, and bobwhites. The caterpillars that fed on elms are like a who’s who of moths and butterflies, including many of the moths you might see at your porchlights this spring. Double-toothed prominent moth caterpillars feed only on elms. They bite into a leaf and then rest there, so their jagged backs appear like the missing leaf edge. It is surprising that this camouflage works, since elm leaves are emerald green, but the caterpillars are pale seafoam blue and green.

English Ivy: Coming to a woods near you

This is an article I wrote for the January issue of the Parkwood Inside/Out, serving the Parkwood community, next to Northeast Creek in southern Durham.

English Ivy: Coming to a woods near you

Now that Parkwood’s green areas are bare, the full extent of the English ivy problem is plain to see. In places behind Newhall, Euclid, Revere, and between Highway 54 and Euclid ivy thickly covers the ground, smothering native vegetation, including the next generation of canopy trees, creating what might best be called “ivy deserts.” A few native and non-native plants do sprout through the ivy, including poison ivy, but the spring beauties, trout lilies, bluets, pink wood sorrel, pussytoes, and other flowers and forbs that should gild the forest floor are excluded. Ivy might affect invertebrates living in streams flowing through an ivy-filled woodland and change the soil, because ivy has nitrogen-rich leaves, a vital plant nutrient. It can carry bacterial leaf scorch, which infects trees such as maples, elms, and oaks. Ivy vines thickly festoon trees, which might make them more likely to fall, though there is some controversy, and less able to get to sunlight.

Once in the canopy, ivy gets enough sun to flower and produce clusters of black fruits, which birds spread into new areas. In my yard there is some ivy kept under control in pots, but in the last 10 years a lot of ivy has crept in through seeding. Without pests or diseases, cold weather is probably the main factor limiting ivy here, by preventing fruit production and temporarily stopping photosynthesis, an advantage evergreen ivy has over deciduous plants. For this reason, ivy is not a major problem further north, but it is rampant in the Pacific Northwest.

As its name suggests, common or English ivy (Hedera helix) is native to the continent of Europe, as well as the Middle East and north Africa, but it was introduced here starting in the 18th century. In its native range it is kept in check and is a valuable food source for birds, some of the species that have become problematic introductions here, such as European starlings and house sparrows.

English ivy is in the same family as ginseng, so it is not a relative of poison ivy or Virginia creeper (in the cashew and grape families, respectively), but I thought it was related when I took a large cut stem and pressed it to my wrist to see what would happen, and my skin blistered, but less intensely than it would with poison ivy. I’m pretty sure it was an ivy stem, and not Virginia creeper, and some people do react to ivy, but from a different toxin than that in poison ivy.

Ivy has evergreen, palm-shaped leaves with three to five points in shade, but they become more lance-shaped in the sunny treetops. The vines appear hairy because of glue-producing roots, while vines high in the treetops lack roots. Stems can be almost a foot wide, and reportedly a 433 year old vine in Europe was more than 20” across. Ivy has tiny and inconspicuous yellowish flowers that appeal to insects with a short proboscis, such as flies, wasps, and moths. The resulting fruit, technically called a drupe, contains a few hard seeds and a toxic glycoside that sickens humans and can make birds vomit. Still, the fruits are nutritious and fatty, and are often eaten by robins, mockingbirds, and cedar waxwings. As with some other non-native plants, human disturbances, such as new roads, give ivy inroads into new areas. There is a lot of ivy in Parkwood now, but it is rare or nonexistent in intact woods nearby. Livestock and deer can apparently eat the leaves, but don’t appear to be making much of a dent in the problem. Non-native rats might be the main animal that can use an ivy desert.

Other than landscaping, people have used ivy for its antifungal and antibacterial properties and in dyeing, tanning, and varnish resin.

Controlling English ivy and other non-native plants is a good New Year’s resolution. Many non-natives can be grown without causing too much trouble for native vegetation and the neighbors. There are more controllable non-natives, such as the groundcovers Vinca minor and Vinca major (they are similar, but V. major is larger and possibly more difficult to keep in check), which only spread vegetatively, but they spread a lot in shade. There are also many native alternatives. Crossvine is an evergreen vine with showy spring flowers that attract hummingbirds. Yellow jessamine is also evergreen and showy. Virginia creeper is a pretty deciduous vine with red fall foliage and dark blue berries. There are several evergreen groundcovers, such as doghobble, Galax, and partridgeberries (common in Parkwood).

Stream and bamboo cleanup

NECSW is actively participating in the volunteer effort to manage the Parkwood bamboo grove and clean up the Euclid stream. Our vision is to manage the bamboo grove to create a productive and esthetically pleasing public space. A healthy grove is uniquely beautiful, is a good habitat for birds, reduces rainwater runoff from surrounding land, and offers a pleasant parkland for walking and contemplation. Three of our members joined six other volunteers for several work sessions this past week.

Fish to watch

This is from the June issue of the Parkwood Inside/Out. It might be past time for some of the behaviors described, but all summer the daily lives of fish are easy to observe, or easier than in winter.

Our next meeting is scheduled for July 13th at 3pm at the Parkwood Volunteer Fire Department. [The meeting has been moved up Seaton Road to the Parkwood Village Pool.]

NECSW was represented at a community consultation in June about a proposed apartment development at the intersection of 54 and Revere Road, but no neighbors attended.

Fish to Watch

June is a good time for fishwatching in the many waterways in Parkwood, as many species enter shallow water to spawn, often in bright breeding colors and exhibiting complex behaviors.

In Parkwood Lake there are swirling black masses of cute baby catfish, guarded by their parents, camouflaged in the murky water. The babies, or fry, are tadpolelike, with big heads and fins, but short tails. They are a species of bullhead catfish, probably black bullheads. In summer a pair swims in circles to excavate a round nest among plants or under a log. The parents guard their many eggs for the few days until they hatch and then stay with them until they grow to about two inches. Later in the summer light-colored fry can be seen darting alone over the bottom to deeper water when a person approaches the shoreline. When caught, bullheads hold their front pectoral and dorsal fins rigid, exposing sharp spines. Small madtom catfish inject painful venom through these spines. Bullheads grow to around a foot and a half long, but the Lake’s channel catfish can grow to around four feet. Channel catfish are grey, slender, and have sharply forked tails. Both channel catfish and black bullheads were probably introduced to this part of North Carolina from the Mississippi River basin.

The nests of sunfish species honeycomb the shoreline of the north Euclid Pond. There are many species, often lumped together as panfish or bream, but these fish are probably bluegills and/or pumpkinseeds. Their colors are hard to see in the water, but bluegills are blueish with stripes and males have red throats now while pumpkinseeds are reticulated with orange and blue. Most sunfish have a black opercular lobe behind the eye, and this is plain black in bluegills, but bordered with orange and white in pumpkinseeds. Males use the motion from their fins to create nests, where they court females. Smaller males try to get in to fertilize the eggs by mimicking females or sneaking in when the owner is distracted. Males guard the eggs and fry until they leave the nest. Sometimes sunfish will even nip at feet placed close by, if they don’t know a human is attached! Surprisingly large sunfish can live in Piedmont brooks and in summer sunfish travel far upstream from the Lake. Largemouth bass are a species of sunfish, and they create correspondingly large, isolated nests.

The minnow family, the biggest family of fish, seems more abundant in clear rocky streams than in suburban lakes, but there are some species in Parkwood. Common carp are gold-colored minnows with short barbels on the corners of their vacuum-like, down pointing mouths. There are carp three feet long in the Lake. To breed, groups of one or a few females and several males enter weedy areas and carry on with splashing and jumping. Carp were introduced from the Old World as a food fish. Japanese koi are colorful, long-lived, and sometimes expensive domesticated carp. Carp tolerate poor water quality and are eaten by predators like otters in Northeast Creek, but they degrade habitat for native fish by uprooting aquatic vegetation and muddying the water. In late summer large carp can be seen gulping at the surface of deep pools in the Creek, such as below the American Tobacco Trail bridge. There are or were large goldfish in Parkwood Lake. Wild goldfish are drab and can grow over a foot long. They are non-native and can hybridize with carp. Small shiners, of which there are many native species, can be found in Northeast Creek and possibly in Parkwood Lake.

The Lake’s ever-present, nondescript grayish “minnows” are actually mosquitofish, Gambusia affinis, basically a wild guppy, and have black spots and a neon violet sheen up close. The large females have a large black spot and give birth to live young. If you look closely, their mouths are turned up, to pick off insects such as mosquito larvae, breathing at the surface. The Lotus Pond doesn’t have much flow in the summer, so some guppies are afflicted with a white fungus on their fins.

In nearby weedy beaver ponds, if not in Parkwood Lake, there are toothy bowfin, also called dogfish, living fossils that can breathe air and make bass scatter. Males guard schools of young until they grow to about four inches. It would be cool to see a prehistoric-looking longnose gar, but I have only heard of them being seen at Westpoint on the Eno and maybe in north Raleigh. Chain pickerel with ducklike snouts also lurk in weedy beaver ponds and wetlands. Pickerel are lunging predators, cylindrical, with fins set far back, so they can dart out at prey. On the other hand, sunfish have a pan-shape that lets them catch small prey up and down the water column. Shoals of filter-feeding shad sometimes ruffle the surface of Parkwood Lake. In Northeast Creek there are many small species, such as darters and mudminnows.