Pay attention to nature's cycles, marked by plants and animals thtat are cued by the subtleties of season and climatic changes.
When will the leaves drop? When will the lilacs bloom? Our essayist Margaret Roach delves into phenology, the science of when things happen in nature’s life cycle as she notes the seasonal calendars for plants and animals.
There are no alarm clocks here.
Like the other animals of this streetlight-free, off-the-beaten-path territory,
I awaken at some mostly imperceptible signal that nevertheless literally moves me. I say mostly, because in spring I know just what reveille is: Who could sleep through the birds’ swelling dawn chorus at 4-something a.m.? Otherwise the trigger is stealthier but equally irresistible. Uppy, uppy, as my mother invoked on school mornings long ago.
I suppose you could say it is nature’s clock that jostles me now when it thinks the time is right, but lately it is nature’s calendar, officially known as phenology, that has my other-than-dawn attention.
This study of the recurring life-cycle stages among plants and animals tracks their timing and how the “phenophases”—changes such as leaf-bud break or flowers opening, leaves coloring or dropping—relate to factors of weather and climate, and also to what insects and other animals are up to. Not just “the peepers peeped” or “the sugar maple leaves are turning,” or even “spring seems early,” but actually taking notice of and recording co-occurring shifts.
Phenology has my attention because, frankly, I crave reassurance—or at least a shred of understanding. We could just keep talking about “the weather,” that perennial conversation starter among friends and strangers alike, but lately there is no comfort to be had there (unless one finds comfort in commiseration about seeming chaos). I’ve instead sought comfort on the website of the USA National Phenology Network, a partnership among public agencies, nonprofit organizations, scientists, educators, and even citizen scientists—volunteers including gardeners and amateur naturalists like me. Their Nature’s Notebook program, where novices and professionals alike record observations, is celebrating its 10-year anniversary and the accumulation of more than 12.5 million such reports. Special regional campaigns, such as dogwood or lilac
bloom or the emergence of mayflies, also invite our participation.
It comforts me to learn that even the simple act of noting the phenophases of a single tree through the year each year—perhaps that dear old sugar maple out back—is welcomed and has value. Scientists will use the pool of such shared data, adding up to vastly more information than they could ever collect themselves, to inform decisions about natural-resource management and conservation in a changing climate and to discover which species are adapting fast enough to stay ahead of shifts—or not. They, too, are uneasy about what is going on, and they are essentially asking: Can we each commit to witness the lifecycle moments in at least a single tree, in the name of hope?
Last year, I was preoccupied with asking “What happened to fall?” when so many trees and shrubs here in Nowheresville failed to drop their leaves on time, at least to my perception.
I am a gardener, guided for decades by the seasonal rhythm I thought I knew but recognize no longer. I want my weather groove back, but autumns like that (or 73 degrees in February sandwiched between days of thick ice and a fresh snow) defy the possibility. Among last autumn’s recalcitrants were more than just the usual suspects—the beeches, the oaks, and witch hazels that in many or even most years refuse to get naked in a hurry. Other woody plants took their sweet time, too, as if somebody had forgotten to set the alarm, though in this case one to indicate when to sleep, not awaken.
The phenophase of leaf drop is no accident. Deciduous trees and shrubs are meant to respond as the day length decreases and triggers chemical changes in the area near where leaf meets stem, called the abscission zone. The enzymes signal the leaf to disconnect from the plant’s circulatory system and prepare to fall off. But weather can interfere—a too-early freeze, before the enzymes did their thing, might mean the leaves don’t reach their breaking point and just hang on.
That phenomenon—dead leaves hanging on—is described by one of my favorite science words, marcescence. When it occurs outside the usual suspect species, though, I love the word less.
Lately there is the stream of incoming ruby-throated hummingbirds moving through en route south—far more individuals than I see in spring and summer—and also the first flaming outburst from the roadside sumacs, both duly noted for scientific posterity. I wonder anxiously how fall will unfold; last time it had me raking way past Thanksgiving when those leaves just wouldn’t—or couldn’t— let go, and I am likewise resisting letting go of my long-held familiarity with seasonal progressions.
Timing is everything—whether for a gardener, plant, or bird, which times its nesting to coincide with a peak supply of caterpillars to feed the growing family or follows the late-season trail of fruit, seed, or nectar to its wintering grounds. Conscious now of the phenophase concept, I try to move beyond looking only for evidence that supports folksy wisdoms such as “plant peas when the peepers peep” or “plant potatoes when the shadbush blooms”—the mnemonics I learned to garden by—and observe more keenly some of the dominoes in each interdependent sequence.
Yes, I know: Nature’s stunning interconnectedness is far too complex to grasp in a single lifetime. That does not stop me from trying in my tiny, layperson way to make sense of just enough bits and pieces so I can feel part of something—both as one animal species in the biological world and as a follower of the collective awareness and advocacy the network of observers represents.