Wild Ideas: Can’t see the trees for the forest  


While adult zebra swallowtail butterflies nectar on a variety of plant blossoms (strawberry in this photo), the pawpaw tree is the sole host of its caterpillars. Photo by Pam Owen
While adult zebra swallowtail butterflies nectar on a variety of plant blossoms (strawberry in this photo), the pawpaw tree is the sole host of its caterpillars.
Photo by Pam Owen


Sometimes what is most helpful in identifying a tree — its leaves — can actually be a hindrance when it’s in a forest full of foliage.

I’ve mentioned the Spring Road, an old logging road that is one of my favorite short walks where I live, many times in this column. I spend a lot of time contemplating and enjoying the forest view from a chair at the end, which offers an increasingly good view across the hollow this time of year. This trail has so many spicebush and tulip trees that, when the forest has leafed out, they are all I tend to see above the forest floor unless I go out of my way to see others. Often I’m focused lower down, searching the forest floor for mushrooms and critters.

When I have taken the time to look more the diversity of forest along the Spring Road, which I did on and off this summer, I have spotted some American hornbeam, sassafras and some other tree and shrub species. But sometimes fall, after most leaves are gone, reveals more, opening up the forest so individual trees stand out, even some I’ve looked at almost daily, sometimes twice a day. That’s happened to me twice in the past week.

The first new tree I discovered was a young mulberry, at the very beginning of the trail. When the trees around it shed their leaves, I noticed the mitten-shaped leaves that were left on one tree. I had no clue what species it was when I found it, so I used the Virginia Department of Forestry’s (VDOF’s) excellent, slender guide, “Common Native Trees of Virginia.” (Go to “Identification of Trees, Shrubs and Woody Vines” at dof.virginia.gov/infopubs to download a PDF version, or to order a hard copy for the cost of shipping.)

Although the book has a key, the leaves were so distinctive on this tree that I found it — or at least our native species red mulberry — quicker by just leafing through the book, as it were. The problem was that the native mulberry included is similar to the white mulberry, a species introduced to produce silk from silkworm moth caterpillars. While the profile on the red mulberry mentions the white, the book doesn’t offer points for how to distinguish these related species. For that, I turned to the Peterson field guide, “Trees and Shrubs.”

I was lucky to have found leaves on the mulberry tree at that point, which fell off a few days later, because that made ID much easier than just looking at bark, limbs and leaf scars. Turns out the shape and texture of the leaves of each species differ somewhat: our native tree’s leaves are hairy beneath, while the white’s are not. And the bottom edge of the red mulberry leaf is even, while the white’s is not. That said, leaf shape, especially, can vary quite a bit even on the same tree, so I was glad I’d taken photos of enough of the leaves to confirm the ID. Unfortunately, this mulberry was the foreign one, which is much more common than the native, according to plant experts I consulted.

Another tree revealed itself to me along the now mostly denuded Spring Road this past week. The leaves were very long (the largest, around 13 inches) and wider near the tip. My first thought was that it was a chestnut oak, but the leaves were not serrated along the edges, ruling that out. It finally struck me that I was staring at a tiny grove of pawpaws, although the VDOF guide says the leaves are only supposed to be 5-11 inches long.

Pawpaws are slender, even spindly trees, and can easily blend into a thick forest, but it was still amazing I hadn’t noticed them. If they’d had fruit during the summer, I think I would have, but these could be too young. You can bet I’ll be checking them again next summer. What really should have tipped me sooner to their presence was the habitat — along a stream (albeit a relatively small one) in somewhat open forest.

From time to time, I’ve looked for pawpaws along streams elsewhere on the property, hoping to find some in fruit, which I haven’t tasted since I was a child. Although I lived next to a grove of pawpaws at a previous house, and kept checking them regularly to see whether the fruit was ripe (brown) enough, it seemed that wildlife — likely raccoons, opossums, squirrels or birds — always beat me to the ugly looking but tasty fruit. Pawpaw are also the sole host of the beautiful zebra swallowtail butterfly.

While I do admit I’m more of a critter person, I am trying to learn more about plants, which are equally as important to our ecosystems. I’ve gotten better at identifying trees, but with these two species, I just couldn’t see the trees for the forest.

© 2016 Pam Owen