COLUMBUS, Ohio — Maple syrup production could be impacted by climate change, according to Dr. Aaron Wilson, Climate Specialist with The Ohio State University’s College of Food, Agriculture, and Environmental Sciences. During a webinar hosted by CFAES Woodland Stewards Program, Wilson shared how changes in climate conditions could impact maple syrup production.

With weather records dating back to the mid-1800 researchers have a good handle on temperature and precipitation averages in the United States, Wilson said 2021 was the seventh warmest year on record.

“A lot of areas in the world are warming up,” said Wilson. “When the atmosphere warms up the carbon dioxide and evaporated water becomes warmer as it absorbs infrared radiation from the earth’s surface, trying to escape to space, temperatures will rise.”

Wilson said one of the most complex aspects is the water cycle. 

“Warmer temperatures drive more evaporation from the soil,” said Wilson. More evaporation means more water vapor is lifted into the atmosphere, so when a front comes along, wringing water out of the atmosphere, it means more rain falling in a shorter amount of time because there is more water in the atmosphere.”

Wilson added that there is roughly a 6 to 7 percent increase in moisture for every two-degree temperature increase. 

“The loss of Arctic sea ice means more open water, which is darker in color and absorbs more radiation,” he said. “That sets the jet stream in motion and makes the weather more variable during the winter and also results in more major disasters. Seasonal temperatures are warmer than they had been in the past and precipitation is increasing.”

When it comes to maple syrup production, warmer temperatures and precipitation can stress the maple trees especially if rainfall decreases. Wilson added that while the weather overall is getting warmer and wetter, there are still drought conditions across the Midwest and the Ohio Valley.

“From a forestry perspective, these changes in temperature and precipitation impact our decisions when we think about forestry and the trees we plant today, and what they will look like in the future,” said Wilson. “We could see up to an eight-degree increase in temperature and a dramatic change in moisture. We could see fewer nights falling below 32 degrees. But a lack of snowpack could cause other problems, like disease pressure, root health, and other issues caused by the lack of snowpack.”

Producers will see a longer growing season, warmer temperatures, higher humidity, more rainfalls, and more intense rainfalls.

“We need to weigh the opportunities and the challenges,” said Wilson. “Opportunities such as longer growing seasons, new crops grown in new areas and new marketing opportunities, longer grazing periods, reduced maintenance costs and opportunities for increased trade.”

He said challenges include additional and sustained heat stress for both humans and livestock, lower food productivity and reduced quality, an increase in weed, insect, and disease pressure, an unpredictable growing season, an expansion of problems with invasive non-native plants and animals expanding their range, increased flooding and the health risks associated with flooding, increased transportation costs, reduced water quality caused by soil loss, runoff, and contamination, along with an increased potential for summer droughts and seasonal water shortages.

Wilson said with increasing temperature shifts, growing zones and species related to those growing zones could change.

Wilson said Kristin Giesting, a liaison between the USDA’s Forest Service and the NRCS compiled a list of potential challenges to the maple industry and compiled a list of resources for maple producers on a website at www.fs.usda.gov/ccrc/topics/maple-syrup 

Wilson shared Giesting’s list of four areas that producers need to consider. First, they need to consider the availability of trees to tap.

“The sustainable habitat for the sugar maple is likely to decline in most of the United States by 2100, especially in the southern and southwestern part of the range, but there could also be acclamation,” said Wilson. “Some expansion of the sugar maple habitat is likely to be more of a possibility in the Great Lakes region, Maine, and southern Canada.”

A reduced snowpack in the winter can impact tree health by causing root die-back and reduced shoot growth, and deeper frost depth which can impact growth. More frequent spring frosts can negatively impact trees that respond to warmer weather by breaking into bud earlier. There could also be a decline in the growth mature trees related to rising temperatures. 

Wilson said another factor is that the tapping season starts earlier and is more variable.

Climate change can also affect sap quality, as climate change is likely to influence sugar content, mineral content, and the secondary metabolic chemicals of sugar maples. 

“Warmer summer temperatures may reduce sugar content by impacting respiration rates and carbon storage,” said Wilson. “We are seeing a lot of changes in optimal production, which brings up the question about the viability of the maple industry.”

Wilson said climate change is happening and we are experiencing the effects.

“Humans are causing it, but we can do something about it,” he said. “We can stop or limit climate change by reducing greenhouse gas emissions. We can change the infrastructure by planning our behavior to adjust to climate change impact, or we can suffer by facing the consequences of failing to mitigate or adapt.”

Wilson said there are several good resources out there to help producers take advantage of changing their production strategy.

“How producers address climate change is going to vary, based on their elevation, geography, the condition of their stands, and the species in their stands,” he said. “All of these factors are going to come into play, so it is important to remember that adaption is a local process.”

Wilson shared several strategies to help producers deal with the challenges. 

“Producers need to consider their geography when adopting a strategy for their maple stand,” he said. “They need to look at the diversity of species in their stand to include birch and red maples. They need to adapt to new and improved technology and possibly increase the number of taps in their stand.” Other strategies producers might want to use include shifting their season to take advantage of the sap flow; possibly having a shorter season, and limit the environmental stressors to decrease the effects of climate change.

“The challenge is to think about maple syrup production under these conditions,” he said. “But if we don’t take action, ultimately the industry will suffer, especially across this region, so it is a good idea to have a management plan in place.”