By Joyce Fry
It’s spring now, but neither the oak (Quercus sp.) nor the white ash tree (Fraxinus americana) in our backyard are sprouting new growth; nor will they. Those trees are dead and are now called snags. Most people cut down dead trees, feeling that they have outlived their usefulness. I take issue with that! Let me explain.
When we first bought our house in the rural northern Franklin County, KY area, the oak was already a snag. Being avid birders, we noticed that its dead branches and trunk frequently hosted several interesting birds well within view of our picture window. We determined that the oak snag was far enough away from our house that it should not pose a hazard, so we elected not to cut it down. Instead, after many years of coaxing, we succeeded in training a trumpet creeper (Campsis radicans) to climb up its trunk nearly to its crown, about 40 feet.
Trumpet creeper, also known as Trumpet vine, is native to Kentucky. It sports lovely orange, red-orange to red tubular flowers from May through August. Ruby-throated hummingbirds (Archilochus colubris) (Kentucky’s most common hummingbird species) visit the tubular flowers to feast on its nectar, and in the process, they cross-pollinate its flowers. A pretty good deal for a plant whose seeds, sap and leaves are toxic. This plant is also known as the “cow itch vine,” because contact with its leaves can cause contact dermatitis, apparently not to hummingbirds, though.
Many insects feed on this plant, including planthoppers, mealy bugs, scale and white flies, all in the order, Hemiptera, and produce “honeydew,” their sweet excrement on which ants feed. Insectivorous birds, and insect predator species are attracted to this microecosystem.
Another phenomenon we observed with Trumpet creeper was the delightful spectacle of Baltimore orioles (Icterus galbula) and summer tanagers (Piranga rubra) slicing open the flower tubes to consume the nectar. We enjoyed the kaleidoscope of orange, red and yellow of the birds and flowers all glowing in the sunshine.
We’ve experienced the excitement of seeing numerous birds alight on the branches of the oak snag, including great-horned owl (Bubo virginianus), bald eagle (Haliaeetus leucocephalus), loggerhead shrike (Lanius ludovicianus), and turkey vulture (Cathartes aura). More commonly, though, American goldfinch (Spinus tristis), tufted titmouse (Baeolophus bicolor), Carolina chickadee (Poecile carolinensis), Northern cardinal (Cardinalis cardinalis) and every Kentucky resident or migratory woodpecker species common to Kentucky use its branches in anticipation of their turn at the feeders below.
Although we don’t know what caused the oak tree’s death and rebirth as a snag, we watched in sadness as our very large and beautiful ash tree fell victim to the non-native emerald ash borer (EAB) (Agrilus planipennis). Much of its once gray, rough diamond-shaped bark peeled off in huge chunks in the aftermath of the beetle’s larvae having fed on the tree’s phloem, killing the tree in the process. Phloem are the structures that transport sugars and protein from the leaves where they are produced, to the rest of the tree. It’s mostly bare, skeleton-like trunk bears numerous s-shaped scars from tunnels produced by the beetle larvae.
Prior to this infestation, the ash featured lavishly green compound leaves during the growing season, which turned a lovely reddish-purple in the fall. The fruit of the female white ash are seeds housed in a flat oar-shaped case, called a samara. Samarae are often referred to as “helicopter keys,” because when they fall from the tree, they swirl like a helicopter. Wild turkey (Meleagris gallopavo), bobwhite quail (Colinus virginianus), Northern cardinal, squirrel (family Sciuridae) and mice (Mus spp,) feed on the seeds of the ash tree.
Although the EAB infestations have killed scores of Kentucky’s ash trees (it has been estimated that up to 10% of our forests were made up of ash tree species), remarkably, there is at least one silver-lining, i.e., they have left snags in their wake, offering animal accommodations, and harboring insects behind the still-clinging bark and crevices for insectivores. The populations of woodpecker species, white-breasted nuthatch (Sitta carolinensis), Carolina chickadee and tufted titmouse, and all cavity-nesting birds, have soared in our area.
“Speaking” of nest cavities, our ash snag possesses one that appears to be highly coveted. Over the span of several weeks one year, we observed a red-headed woodpecker (Melanerpes erythrocephalus), and several red-bellied woodpeckers inspecting it. One red-bellied woodpecker (M. carolinus) we watched began renovating the cavity by throwing nesting material into it. He stopped renovation periodically to drum on the trunk near the hole, most likely to attract a female. Much to our surprise, a seemingly indignant flying squirrel (Glaucomys Volans) suddenly exited the hole, discarding the added nesting material and chasing the woodpecker around the trunk until she scared him off.
Although it may not be wise to leave every snag on your property, especially in an urban or suburban setting, think twice before having one removed. Even in death, trees can be an asset, as well as the source of much entertainment.