Quick, I have to talk about old leaves before new ones happen. Saw a tulip poplar headed toward budburst this morning, so I need to hurry.
Have you noticed how some deciduous trees drop every leaf in fall, but others hang on to leaves all winter? Oaks, for example? I’d wondered about oaks for years, and was never satisfied with the “they used to be evergreen” explanation, despite seeing always-green Live Oaks just one state over. Didn’t all trees evolve from conifers way back before the Cretaceous debut of flowering plants? So, are oaks somehow “less deciduous” than maples or hackberries, which consistently drop every leaf directly onto my lawn each fall?
Marcescence. That’s the word that describes the phenomenon of winter leaves that linger. It doesn’t explain it, but at least it names it. From the Latin marcere / wither. The leaf’s food supply is cut off, but the leaf isn’t. Apparently, the word is used with fungi too, to describe types that dry utterly but revive with a bit of moisture.
After I started Naturalist training, I noticed beech trees kept winter leaves, too: pale, peachy-tan leaves warm against silver trunks. Wherever the gray hills of Warner woods are splashed with that peculiar color—peach/brown/yellow/gold—that’s where young beeches march to the ridge.
They also make music. On a quiet walk, the only leaves that aren’t under my feet are beech rattling overhead at the slightest wind.
Research with the word marcescent led me to one more local species to join oak and beech: hop hornbeam (Ostrya virginana). I hadn’t noticed these because they weren’t on my usual beat. But they were. At the Couchville Cedar Glade bioblitz our team stumbled streamside among young, fluttering trees I assumed were baby beeches. But when I stopped to admire the buds, expecting long, pointy paintbrushes, I found short and pudgy: hop hornbeam. What a thrill. The textbook marcescent trio is now personal. I’ve seen all three Species Most Likely to Linger, and in all their withered glory: oak, beech, hop hornbeam.*
None of this explains why, though. Or explains what advantages leaf retention may offer.
I gathered a few opinions:
The Beech family occupies a “middle ground between evergreen and deciduous.”
Marcescence is an evolutionary “delay.”
Marcescence is a “juvenile trait,” for younger trees and lower branches.
Lower branches cloaked in dead leaves can protect buds from browsing deer.
Lower branches cloaked in dead leaves can provide insulation during snowfall.
Marcescence can reduce moisture loss: Oak and Beech tend to grow on dry, sometimes infertile sites.
Leaves that fall in spring act as timed fertilizer for the soil, just when awakening trees are better able to use it.
All these sound plausible, but there is one confirmed benefit: winter leaves help me identify trees.
We don’t have to remember marcescence or how to spell it, but the idea comes in handy as another clue to what’s around.
Even a short, neighborhood dog-walk turns up fistfuls of late winter treasure: acorns to ID, a flap of birch bark, and—thanks to recent chainsaw work—as much fresh hackberry shavings as can fit in a dog poop bag. But even I know the magic of these seasonal accessories has an expiration date. Once spring really kicks in, will acorns and bark be as irresistible?
Once you start stealing Christmas trees, you may not want to stop. I’ve got three right now. The best was the dried cedar by the curb a block over. Izzy hauled it home for me, dragging it behind like a giant peacock tail.
Discarded evergreens make great temporary brush piles for winter birds: they give cover to species loathe to fly up to a birdfeeder. Ground-feeders feed on the ground. Two examples: the visiting White-throated Sparrows and the year-round Mourning Doves. Asking a White-throated Sparrow to spend all day on a tube feeder four feet off the ground is like asking me to go sit at the bar at Applebee’s. It’s not going to happen. Continue reading “Stealing Christmas Trees”→
Last week’s wind took our neighbor’s big tree down just after midnight. The neighbor is absentee, unreachable and still doesn’t know his tree ended up in Next Door’s kitchen.
Oh, the many, many tree cookies I could have cut with a power saw and a powerful arm (I have neither). I did sneak over and haul back anything I could carry, like this curved strip of shreddy fibers, clean, white, strong. Continue reading “Hackberry sapwood”→
Osage orange fruit. Hedge apples. Monkey brains. Maclura pomifera.Yellow-green, squiggly, hairy spheres the size of grapefruits. If these are underfoot on a fall hike, I guarantee someone will mention the purported insect and/or spider repellant properties of an Osage orange. Rumor has it that a few of these bowling balls under one’s bed or kitchen sink will convince critters to stay outside. If this were true, I’d superglue a row of fruit along every baseboard of my house. Continue reading “Osage Orange as Bug Repellant and Mammoth Snack”→
Last night’s freeze made the ginkgo trees give it up, give it ALL up. I woke to bare branches and eddies of golden fans. Did it happen all at once? Did the tree heave a sneeze when the thermometer hit below 30 and then FFHOOOOM! eject every leaf?
Apparently, ginkgos are known for sudden synchronized leaf drop. I sure would love to see it happen. I need to compare it to the Pixar version that lives in my head. Continue reading “Ginkgo Leaf Surrender”→