RENEE MONTAGNE, host:
We head now to New England in our Climate Connection series with National Geographic. The region is wrapping up a perfectly beautiful fall amidst a lot of bad news about the forest and its trees. Climate scenarios project that rising temperatures could send some trees packing for Canada, among them that stalwart of New England, the sugar maple.
We sent NPR senior correspondent Ketzel Levine for a closer look at the tree.
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KETZEL LEVINE: Its leaves are peach, orange, mango - definitely mango. The tree's a thunderhead of foliage, a cream sickle colossus.
LEVINE: Wow. Look at the girth on this one.
Ms. MARTHA CARLSON (Sugar Maple Grower): Yeah.
LEVINE: How big or round do you think she is?
Ms. CARLSON: Well, I brought my measuring tape.
LEVINE: These woods belong to the Carlson family. Martha Carlson walks her tape around the enormous body of the tree.
Ms. CARLSON: It's like you're on the dark side of the moon right now.
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LEVINE: Heady stuff to see in this northeast woods - a sugar maple four feet across. She has other favorites for maple sugaring, and stories - lots of stories - about each one.
Ms. CARLSON: I was tapping the trees right beside my house and it was a warm day. It was like 34 degrees and the sap was just pouring out. And then a cloud went over and it stopped. And you can almost hear the tree click off.
LEVINE: Exquisitely sensitive, shuddering at the slightest chill, the sugar maple has weathered ripples of climate change. I find this out from an historical ecologist with an enviable view.
Mr. CHARLIE COGBILL (Historical Ecologist): Charlie Cogbill sitting in front of the Calais Town Hall, taking a look at the scenery. Mighty pretty out here.
LEVINE: Pretty isn't the half of it here in northeastern Vermont. Sugar maples, red maples, dollops of butternut and peach; to me a still life, to Charlie Cogbill a diorama - millennia of Acer saccharum.
Mr. COGBILL: They were actually more abundant 4,000 years ago, but they've been here for 8,000 years.
LEVINE: His focus today is just a horseshoe toss into history and into the archive of the Calais Historical Society.
What was this made from?
Mr. COGBILL: This is parchment - animal skin, probably sheep skin.
LEVINE: In his hands, which fairly tremble with excitement - the original 1763 lotting map of Calais, a grid of what the town will be. But more than that, it's a key to the big trees that were growing here before white settlers divvied up the land.
Mr. COGBILL: If you notice, at the corner of each of the lots is written maple, spruce, beech, maple...
LEVINE: The tally will favor beech trees, but by the late 1800s, sugar maples dominate, not natural selection - human predilection. Early Americans were crazy for this tree, a ready-made foliage festival, winter syrup on snow, durable white wood. Instantly iconic, a pair by the front door read like a New England sampler. As does this pair glistening in the rain, guarding a black shuddered New Hampshire colonial circa 1790.
Mr. JAMEY FRENCH: Wonderful gnarled trees. They're in the latter stages of their life. We'd guess that they are about 200 years old.
LEVINE: Jamey French's family is enormously beholding to this tree, for the butler blocks, bowling lanes and squash courts its wood has been priced for, and sold by four generations of this hardwood lumber family.
At heart a steward of the forest, Jamey French has been watching many tree species for signs of decline, particularly the sugar maple, a touchy species living in a landscape of tangible environmental change.
Mr. FRENCH: Multiple species of birds that were not common in your childhood - mocking birds and cardinals and titmice - wintering over in central New Hampshire, that's real change. And you look along the sides of the roads and you see trees that between the salt and the acid rain and potentially the heat and the drought cycles, and you'd think, boy, this is happening right in front of our eyes.
LEVINE: Elsewhere in New Hampshire, back among Martha Carlson's sugar maples...
Ms. CARLSON: I brought my hand lens - oh, here it is. I'll show you this.
LEVINE: We're looking at ugly blotches on a maple leaf caused by a spreading black fungus. The likely culprit: a wet spring. In her graduate degree research, Martha Carlson is also studying sap-to-syrup ratios in sugar maples, wanting to know whether sap is getting more watery, and if so, whether the reason is climatic stress.
Her family's own maple-rich forest looks healthy enough, some black fungus notwithstanding, but it's what she can't see that has her worried about her trees.
Ms. CARLSON: If climate warming is going to hurt them, we need to study them not so much as a resource, but as a patient. If there is something I can do, pruning them differently, giving them more shade, I'd like to know that.
LEVINE: So would eighth-generation Vermont sugar maker Burr Morse.
Mr. BURR MORSE (Sugar Maker): Over the last 20 years we've had more than our share of bad seasons. And it seems like it isn't cold enough.
LEVINE: Burr Morse will tell you that no farmers are more dependent on the weather than sugar makers, many of whom say global warming is bunk. Not Mr. Morse who says he and his fellow farmers began adapting the day they switched to vacuum pumps.
Mr. MORSE: That's what I'll say. Yes, I'll stick my neck out. Some sugar makers might say, no, the reason we went to vacuum is so we can get more sap. If they would be really honest about it, they'd say more sap or the same amount we used to when we had the perfect weather.
LEVINE: It is perfect today - rotund clouds, pastel skies, sugar maples across the horizon. As temperatures rise, these luminous trees may slowly cease to dominate. But they will not turn off their taps, pack up their trunks and leave us sad as mud.
Spruce and fir may be at much greater risk; hemlocks are battling ravenous pests right now. Development, disturbance, human hands seem a greater threat than temperature.
Today, some 78 percent of Vermont is wooded - as much as 84 percent of New Hampshire. The odds, for lumberman Jamey French, still favor the forest.
Mr. FRENCH: Fifty or a hundred years from now, maybe hard maple won't be the most valuable species, but maybe the red oak in this area is back. Maybe the white oak will recover. There was more white oak in our ancestors' times, but they cut all the trees down for boats and barrels and all that stuff. And who knows what it'll be. But I think we'll - our forests will survive.
LEVINE: And with them, the impossible pleasure that is the sugar maple.
Ketzel Levine, NPR News.
MONTAGNE: All this week on Ketzel's blog, Talking Plants, the subject is climate change and the Northeast forest. You can join the conversation at npr.org/talkingplants.