Pay at­ten­tion to na­ture's cy­cles, marked by plants and an­i­mals thtat are cued by the sub­tleties of sea­son and cli­matic changes.

Country Gardens - - Contents - For more in­for­ma­tion, see Re­sources on page 108.

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.

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