In 100 years, maple sap will flow a month earlier

November 12, 2010 By Krishna Ramanujan, Cornell University

As the climate warms this century, maple syrup production in the Northeast is expected to slightly decline by 2100, and the window for tapping trees will move earlier by about a month, reports a Cornell study.

Currently, the best times to tap maple trees are within an eight-week window from late winter to early spring when temperatures cause freezing at night and thawing by day.

"By 2100, we can expect to begin tapping maples closer to Christmas in the Northeast," said Brian Chabot, professor of ecology and and a co-author of a paper on climate changes and maple sugar production that appeared earlier this year in the journal .

Sap flow is related to pressure changes in the trees' xylem, which are tubes beneath the bark that carry sap from the maple's roots up to the leaves. As maple trees freeze in winter, gases are pushed out of the xylem into surrounding tissues, and negative pressure is created within the xylem compared with atmospheric pressure. When the trees thaw, the gases expand and dissolve back into the sap, creating positive pressure. When tapped, the sap flows out because the pressure inside the xylem is greater than outside.

Based on this principle, Chabot and colleagues identified that the best days for sap flow are when diurnal temperatures swing at least a few degrees below freezing at night to a few degrees above freezing by day.

In the study, lead author Chris Skinner '08, currently a graduate student at Purdue University who studied with co-author Arthur DeGaetano, a Cornell earth and atmospheric scientist, scaled down computer models to regional scales to determine daily temperatures for 10,000 locations across the sugar maple's range -- from North Carolina to Quebec to Minnesota, with optimal production areas in the Northeast and Quebec -- from 1970 to 2100. In this way, the researchers could identify daily minimum and maximum temperatures during optimal eight-week windows for tapping sugar maples.

By "backcasting," the researchers validated their models with temperature data, which revealed that start dates for tapping maples in the Northeast are about a week earlier than in 1970.

Under a high carbon dioxide emissions computer model scenario, syrup production will decline slightly in the Northeast, mostly after 2030. According to the study, by 2100, the average number of flow days will stay constant in Saranac, N.Y.; decline by about two days in State College, Pa.; five days in Montpelier, Vt.; and by 10 days in Jackman, Maine. In a more moderate emissions scenario, producers will lose about half as many days in each location. Similarly, in the high emissions scenario, start dates for tapping maples will be earlier by about a month between now and 2100: In Jackman, the current optimal start date of March 11 shifted to early February; in Saranac and Montpelier, the current start date of March 1 moved ahead to Feb. 1; and in State College and Ithaca, N.Y., start dates advanced to mid-January from mid-February.

Maple production south of Pennsylvania will likely be lost by 2100 due to lack of freezing, while production in Quebec may benefit from climate changes, Chabot added.

Explore further: Will maple days move from March to January with global warming?

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2.1 / 5 (7) Nov 12, 2010
Global warming groupies.
2.6 / 5 (5) Nov 12, 2010
I've read a lot of studies about global warming but this one seems to to take the cake , so as it were.

Trying to forecast 100 years into the future for ANYTHING is an exercise in futility. The report authors would long be gone and by then we would with 99% probability just plain run out hydrocarbons. No Hydrocarbons and we're forced to use "eco-friendly" technologies like Space solar Satellite , Nuclear fission etc.

I predict in 100 years global cooling will set in due to plunging CO2 levels.
1.6 / 5 (7) Nov 12, 2010
They can't even predict next week's weather, much less 100 years from now.
3 / 5 (2) Nov 12, 2010
note to self: do not switch the cough syrup with the maple syrup before doing forecasts
1.6 / 5 (7) Nov 12, 2010
"The Polar bears will be fine." - Freeman Dyson
2 / 5 (8) Nov 12, 2010
I hope that somebody checked the numbers this time and didn't mix up 2030 with 2300 like the IPCC did with the numbers 2035 and 2350 in the glacier report... :)
1.5 / 5 (8) Nov 15, 2010
This new, short video explains how government science really works.

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1 / 5 (1) Nov 15, 2010
Skepticus_Rex: Man, that's hilarious. One known typo invalidates an entire body of science? You guys are really stretching.
1 / 5 (4) Nov 15, 2010
"By "backcasting," the researchers validated their models with temperature data, which revealed that start dates for tapping maples in the Northeast are about a week earlier than in 1970"

If they are going +90 years for the prediction, then they should go -90 years for the back-cast to validate the model (or longer). They should also check outcome versus various possible scenarios such as increased/decreased el nino/la nina and large/small solar max/min. The results should be a range with more variation than what they are proposing here. If anyone had predicted the currently observed deviation from expected solar min/max cycles then this study would have more meaning. As it stands, it's difficult to give much weight to the model in this regard. There seem to be a few more unknown factors that should be accounted for in the various versions of possible future outcomes than what they are suggesting.

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