A hike is more than a walk in the woods. It's a chance to exercise sure, but it's also a chance to work out your wild
intellect. When I lead a hike, I usually do a bit of reconnaissance in the months preceding, and again days before the hike. This ritual is to familiarize myself with the trail and to get a sense of seasonal change on a local scale. An experienced naturalist has an understanding of biological and physical features present in the local ecosystem. Part of this sense is so we can provide visitors and fellow hikers with a story of what has been and perhaps, what's to come.
My eyes are drawn to bark this time of year, as our deciduous trees have finished balancing their energy budgets. That is, the decrease in day length (photoperiod) has driven trees to drop their leaves due to a consequential lull in photosynthetic efficiency. This week along Mount Pleasant Loop Trail in Rocky River Reservation, I happened across a mature white ash (Fraxinus americana
) with something odd about its bark. The outer bark of the tree showed bark flicking referred to as, "blonding." This is not a good thing.
| Blonding is seen on the brownish-gray bark of this white ash (Fraxinus americana) near Rocky River Nature Center. A persistent food-driven woodpecker removed vertical strips from the outer bark, ultimately changing the pattern of intersecting ridges. |
Blonding is an effect seen when woodpeckers are in search of bark beetle larvae, such as emerald ash borer (Agrilus planipennis
) in this particular case. The bird literally peels off and flicks away strips of bark in search of a potential morsel of food. I confirmed the presence of emerald ash borer by identifying 1/8” D-shaped exit holes in the bark. The larvae make these holes as they emerge from the tree. Cleveland Metroparks Natural Resources Division has thoroughly mapped the forests for ash trees, allowing for the tracking of emerald ash borer. Resource Managers of the Natural Resources Division watch over the site where the above photo was taken. For more information on emerald ash borer, please check out Cleveland Metroparks Emerald Ash Borer Report at http://cleveland-metroparks.github.io/eab/
Evidence left behind by critters is part of what makes a hike unpredictably interesting. One of my favorite, “Whodunnit?” clues is the pattern left from a migratory woodpecker to Northeast Ohio. The yellow-bellied sapsucker (Sphyrapicus varius
) leaves an unmistakable line of semi-round shallow holes across a tree’s bark. I came across such a case at Great Smoky Mountains National Park on a herpetology field trip in 2008. I’ve always enjoyed looking back at the simple photo every year and gleaning new information. Even at the time of taking the photo, I did not yet know that the aptly named sapsucker drilled the holes to gain access to the tree’s trunk and sap.
| The horizontal lines of round holes were caused by a yellow-bellied sapsucker (Sphyrapicus varius) seeking sap. These patterns are not indicative of infestations of an invasive bark beetle species, but are considered typical foraging from this species. |
If you and your family are into figuring out wildlife clues left behind, come along on a 1-hour Emerald Necklace hike (Tracking 101
) I’ve planned for Saturday, January 24th in Mill Stream Run Reservation. We’ll meet at 10 a.m. at South Quarry Picnic Area for a beginner’s introduction to wildlife tracking using environmental clues left behind by the quiet critters of winter. Call 440-734-6660 for more information.