Cedars aflame – with pollination

Monday, March 13, 2017
Nature’s notebook

A band of light rain passed through the Uwharries on a recent Saturday evening. By Sunday morning, the sky was crystalline blue. Despite a lively northwest breeze, the temperature was unseasonably mild. I was out with the dogs, admiring the tawny field of native grass backlit by the unadulterated sun. Suddenly, a line of smoke appeared along the far edge of the field. The wind whipped it across the road. The smoke hit the base of Black Mountain and churned up the slope. In a matter of minutes, it dissipated into a uniform haze. For a moment, I wondered if I had conjured a fire in a field that’s due to be burned in the coming weeks.

Something similar happened to my parents a few years back. On a balmy winter morning, Mama was sitting on her back porch when she caught a glimpse of smoke. It seemed to be coming from the old farmhouse next door. She called to my dad, and they rushed to investigate. A neighbor driving down Ophir Road also noticed it. He stopped and met them in the driveway. They were flummoxed. They didn’t smell smoke or see flames. Then a gust of wind revealed the source of the smoke – the stately cedar just east of the house. The tree wasn’t burning, but it was clearly on fire – a male spewing its pollen into the air.

Walnut-brown male cedar cones spew pollen. Photo: Ruth Ann Grissom

There are basically two approaches to pollination. Plants with bright, showy flowers produce relatively small amounts of pollen, but they attract insects that deliver it with surgical precision. Plants with inconspicuous flowers rely on the wind, so they carpet-bomb with copious amounts of lightweight pollen. The eastern red cedar (Juniperus virginiana) obviously falls into the latter camp. The pollen emanates from tiny walnut-brown cones clustered at the tips of the branches.  From a distance, the entire tree can take on a rusty hue. Female flowers are similar but much smaller. They sometimes appear alongside the previous season’s fruits, small slate-blue berries with a whitish cast. The cones close once they’ve been fertilized.

Tiny yellow cedar flowers on a female tree, with the blue-black fruits of last fall. Photo: Ruth Ann Grissom

Cedars are one of the earliest trees to bloom in the Piedmont, generally beginning in late winter.  In the days after my encounter with the smoking hot cedars, the website pollen.com blamed junipers in general for the spike of activity in local allergy forecasts, but the eastern red cedar is the Piedmont’s only native juniper. According to the website, many juniper species are considered severe allergens. Not only is their pollen produced in vast quantities, it’s lightweight, dry and dusty. It travels long distances – providing more opportunity for contact – and it’s easily inhaled and especially irritating to mucus membranes. Texans in a juniper-heavy belt across the center of the state refer to the resulting malady as cedar fever.

The Ogren Plant-Allergy Scale (OPALS) rates more than 3,000 common plants on a scale of one to 10. Male eastern red cedars top the chart at 10. (Since females don’t produce pollen, they rank at the bottom.) To put this into context, oak pollen causes widespread misery in Charlotte, but it rates only an eight on the OPALS. Sticky, yellow loblolly pollen is notorious in these parts, but the waxy coating that spackles it to cars and outdoor furniture also makes it harder to inhale and much less irritating. Pines score a lowly four on the OPALS.   

This doesn’t mean we should rush out and cut down all the cedars. (Other than one at Christmas, of course.) Without a doubt, wildlife appreciates cedars more than we do. The trees are associated with early successional habitat, which is increasingly rare in the Piedmont and is essential to the floundering population of bobwhite quail. Cedars provide food and shelter in winter, a critical time when both are in short supply.

[highlight]Hear author Ruth Ann Grissom talk about cedar pollination on the Carolina Outdoors podcast.[/highlight]

Their frequency along fencerows is a testament to their popularity among many bird species, including the cedar waxwing, native to North and Central America. Hosting a flock of these elegant birds is thrilling. Scores will descend on a food source, fluttering from branch to branch and voicing their excitement with a cacophony of high, thin whistles – a spectacle worth the runny nose, itchy eyes, scratchy throat and extra dose of allergy medication.

A cedar waxwing feasting on berries. Photo: Kelly Colgan Azar, Wickimedia Commons (CC BY-ND 2.0). Link to license.