Tag Archives: sphinx

The life and death of an ash tree

Our next meeting will be Sunday, January 26th at 4pm, to plan for Creek Week 2014 (March 15-22) and discuss some development issues, etc. Contact us for the address of the residence where we are meeting.

Below is an expanded version of an article I wrote for the January issue of the Parkwood Inside/Out. This giant ash tree grows beside the stream that flows from the corner of Barbee and 54, through Parkwood to NE Creek at the bridge on Grandale Road.

The life and death of an ash tree

An ash tree in Parkwood is one the largest I have come across. There are taller trees, but this ash is nearly four feet across, beating large ash in the wild bottomlands around NE Creek and the big ash in downtown Chapel Hill. Parkwood’s ash is a little south of McCormick Road, near the intersection with Auburndale, beside the stream in the common green area, and can be seen from the road. Ash trees usually have very straight trunks, but this giant leans southwest and has lost huge limbs to the force of wind or ice over its long life. It is hard to say why it leans. That section of woods is relatively young and this ash is the biggest tree there. It has pale bark, and as a reaction to tilting, it grows more on the leaning side, producing unusually deep 4” furrows, resembling a baleen whale’s throat or treads. In one place the bark is brown, probably from deer rubbing the velvet off their antlers. There are rows of holes created by yellow-bellied sapsuckers, woodpeckers that winter here and tap trees for sap.

During the growing season, the ash’s massive trunk is obscured by understory oaks, dogwoods, and black cherries. American beech, increasingly common in Parkwood, and Northern red oak saplings wait for the ash to fall. This is the only spot I know of where pawpaws grow inside Parkwood, though they are quite common as small riparian trees along NE Creek. The pawpaws probably would benefit from more light, though the site might still be a bit dry for them to produce their sweet bananalike fruit. There is a seemingly innocent sprig of English ivy, a plant which is taking over in nearby sections of the woods, and a Nandina bush with purple foliage, another non-native, but much less invasive. Partridgeberry, ‘wild onions,’ and grape ferns form the herb layer under the ash.

Each ash produces only male or female flowers, and this must be a male tree. Perhaps it is a parent of large ash on nearby Timmons Drive, or even throughout the area.

Our ash is probably a white ash. Green, pumpkin, and Carolina ash also grow in Durham. They look similar, all living up to their scientific name, Fraxinus, the Latin name for ash, which also means spear, and describes their typical soaring shape. Ash have leaves and twigs growing in pairs along a stem, and their pinnately compound leaves are made up of oval leaflets, resembling the leaves of walnuts, hickories, and locusts. In fall ash turn gold, orange, and purple. Ash saplings have smooth gray bark and mature trees have somewhat furrowed or rough bark, depending on the species.

White ash is the most economically valuable ash. High-quality baseball bats are made from white ash, as well as other objects requiring lightweight, strong wood with a spring, like oars, lacrosse sticks, musical instruments, furniture, and bowling lanes. It is also an easy to split, hot burning firewood. White ash has been used to relieve fevers, sores, and snake bites, as a laxative, and as an aphrodisiac, among other medicinal uses. Ash have a long history in mythology, for example the Norse axis mundi/world tree Yggdrasil is supposed to have been an ash, and according to folklore snakes don’t like ash trees. White ash likes well-drained, but not very dry soil and is one of the first trees to sprout in abandoned fields. White and green ash can tolerate shade as seedlings, waiting for their chance to shoot into the canopy when an old tree dies. The big snowstorm that left two feet of snow and ice and other bouts of freezing rain have knocked down most of the young pines behind the Parkwood Volunteer Fire Station, leaving a woods of only ash and winged elm in places. Pumpkin and Carolina ash like wet habitats, and ash are one of the main trees in swamps and bottomlands. Ash trees can be seen next to the Parkwood Association office, where there used to be a trailer, and at the Parkwood Convenience Store, at the corner of Seaton and Revere. Ash of some kind can be found on most streets in Parkwood and are common throughout the Triangle.

Late last summer I watched big pale green, red, and yellow hornworms on an ash sapling at Falls Lake. These were waved sphinx moth caterpillars, but the red markings were unusual. Usually their larvae don’t have any red coloration, but these were mostly red with yellow markings when small and then mostly green, but with red heads, horns, and markings. A few other sphinxes feed on ash, as do caterpillars of black and yellow Eastern tiger swallowtails. These green caterpillars have fake eyes complete with angry eyebrows, to mimic snakes, and if that fails, they can send out bright orange ‘horns’ that emit a smelly fluid. The big, shiny black rhinoceros or unicorn beetles sometimes found under streetlights at the Parkwood Shopping Center also eat ash. Ash have wind-pollinated flowers in early spring, but honeybees and other insects sometimes harvest pollen from male flowers. The winged seeds, or keys, of ash trees are eaten by weevils, mice, and birds such as wood ducks, turkeys, and purple finches. Large ash often have hollows where birds and squirrels can nest. Our ash seems to house a colony of big black ants, judging from the seemingly arboreal ants walking along its trunk last summer. Deer and rabbits eat the leaves while beavers like ash bark. Ash growing around the beaver impoundments on Grandale or elsewhere could host mistletoe.

Native beetles and two species of dayflying moth that mimic wasps bore into living or dead ash trees, but a new ash-boring beetle from East Asia is on its way to killing virtually all ash. Emerald ash borer or EAB reached Michigan in the 90’s, probably in shipping materials. It wasn’t noticed until 2002 and has since spread throughout the Eastern US and Canada, in part because people violated quarantines on firewood and other products. Their grubs tunnel under the bark of trees as small as 1” across, and since these are non-native animals, they come in out of control numbers that girdle our naïve ash, killing them within a few years of colonization. A good online resource to check out is www.emeraldashborer.info .

Earlier this summer emerald ash borers crossed into Granville County from a pocket across the border in Virginia and a quarantine was imposed (see http://www.ncforestservice.gov/forest_health/fh_eabfaq.htm ). This is likely to be the end for Parkwood’s great ash in the near future, when the emerald ash borer gets to Durham, on its own power or by hitching a ride, and a great many beetles could come from it. There is cause for hope – some ash seem to have survived the borer up north, introduced Asian and native parasitoid wasps could help control the beetle, and individual trees can be protected with insecticides that are relatively safe for the environment. Emerald ash borer has a big ecological and economic impact, and even harms human health, so communities in the Triangle should prepare.

You can read more about emerald ash borer in my article in the February issue of Carolina Gardener magazine (www.carolinagardener.com).

Watch out for blooming catalpas this month

This month there will be many showy white flowers on the small catalpa in front of the condos on Revere Road in the Parkwood subdivision in southern Durham. There are actually two very similar species, Catalpa bignonioides, the Southern catalpa, and C. speciosa, the Northern or hardy catalpa. Southern catalpas grow naturally in the Deep South while Northern Catalpas grow in the region where the Ohio joins the Mississippi. The Revere Road tree is probably a Southern catalpa. The species difference is dramatically revealed in spring, when they bloom at different times, but there are some other differences. Southern catalpa flowers have more spots and fewer blossoms per cluster. They also don’t grow as tall as Northern catalpas and there are differences in the seed pods and bark patterns. Apparently the crushed leaves of Southern catalpas have a bad smell. Northern catalpas might be the only ones that have glands at the base of the leaves, perhaps to attract ants for defense. Catalpas resemble royal paulownia, Chinese natives with big leaves and clusters of pale blue flowers in March or April, and have round seed pods. Catalpas are related to native crossvine and trumpet creeper. The word catalpa is supposed to be a native term for this tree while bignonioides refers to a vine with similar flowers and speciosa means ornamental.

Catalpas self-seed here, but are still pretty rare. The only other specimens I can think of are a few at Sedwick and Prospectus Drive, one on Grandale, one growing beside Northeast Creek near Jordan Lake, and several individuals of both species in Chapel Hill and Carrboro. There is a towering Northern catalpa across South Road from Coker Hall at UNC. A week ago it was crowned with white blooms and is probably peaking or past peak by now. There were one or two large catalpas near the corner of Fayetteville and 54, by Crooked Creek. Catalpas stick out because of their peculiar yellowish green leaves and pagodalike canopy. In their native habitat, catalpas grow near waterways and in bottomlands. They seem to prefer full sun, which could be a reason they aren’t more abundant here.

Catalpas were probably planted so widely for their flowers, and sometimes to grow caterpillars for fishing bait. Catalpa wood is sometimes used indoors, but is mainly used for posts, railroad ties, and telephone poles, because it is rot-resistant though brittle. Bark tea has been used as an antiseptic, laxative, sedative, and to treat snake bites and worms, while the pods were also thought to be sedative and to have an effect on the heart. The leaves were used to treat flesh wounds, as was seed tea, which was also used for respiratory problems. Catalpas are also sometimes called Indian cigars, which could be because kids smoked the pods

The flowers are grouped in panicles on the ends of new shoots. When they open, the large frilly white flowers are tubular and have five asymmetrical petals. They have dark purple spots and two yellow lines inside to guide pollinators. Bumblebees, honey bees, moths, butterflies, and ants are among the insects attracted by the nectar and pollen, yet one source says the nectar is toxic to skipper butterflies and ants. Catalpas will probably bloom for a few weeks, and then the trees sprout long, thin green pods all summer.

Catalpas are noticeable again in summer when they attract catalpa sphinx moths. Apparently their only larval food is catalpa, and the adults don’t eat. Like other sphinxes, catalpa sphinx caterpillars are hornworms, with a ‘horn’ on the tail, and they have striking yellow, black, and white stripes from head to tail. They are unusual for hornworms in being social during most of their caterpillar stage, and groups sometimes defoliate even a tree the size of the one in Parkwood. If Wikipedia is to be believed, cropdusting was first used against catalpa worms. When irritated they vomit a green liquid and thrash.

Nothing else seems to eat catalpa leaves much, so the trees are quiet until the brown pods attract angular gray leaf-footed bugs in late fall. As the weather gets cool, the pods split in half lengthwise, releasing winged seeds, while the husks remain on the trees into winter.