Changing Planet: Climate Change and Breakfast



In the Changing Planet: Grapevines and Drought episode, you learned how climate change is impacting one of our countries most important agricultural crops.  But grapes are not the only crop in peril.  In previous Changing Planet episodes, you saw how climate change is affecting crops and leaving them more susceptible to drought conditions, infestations and disease.  In the case of grapes, hotter and dryer climates are affecting the flavor of the grapes and the dormancy period of the vines.  It is hoped that by understanding the genetics of the different varieties of grapes, scientists can determine what is changing genetically in response to changing environments.  Those harvesting maple syrup are also concerned about changing lengths of seasons and the impacts shorter seasons will have on overall production.  In this lesson, you will explore changes in the production of maple syrup and decide if you'll need to find something else to put on your pancakes and waffles!


Lesson Question

How will climate change affect crop production, including the production of maple syrup?


Materials per lab team

Internet connection

Colored pencils

Graph paper


Lesson Procedure

Part I: From Tree to Table


In this lesson, we will focus on maple syrup production in Vermont.  The Vermont maple syrup industry has the highest yield of maple syrup of any state in the U.S.  In fact, in 2010 the Vermont maple syrup industry was valued at over $30,000,000!  To learn more about how maple syrup is produced visit the "How Maple Syrup is Made" at the Vermont Maple Syrup website.  Answer the questions below after visiting this webpage.


  1. Not all maple trees are used to make maple syrup.  What are the 3 main species of maple trees used for maple sugaring?



    What are the characteristics of the maple trees used in maple sugaring?




    Explain the process in which maple trees create sap and how the sap "runs" in a tree.



  2. Describe the necessary weather and climate conditions needed for sap to run up through a maple tree.





    Now that you know the weather and climate conditions necessary for the sap to run up through a maple tree, where do you think these conditions are found?  On Figure 1 below, use a colored pencil to color the areas you think have the necessary conditions to grow maple trees.


    Figure 1: North America.

    (Map courtesy of


    Why did you choose those locations?



    Visit the Forest Service page for the sugar maple and check the range map available on this page.   Use another color on the map above to make corrections to your guess.  Create a two-color key for your map. How accurate were you in your original estimate? Explain.



  3. In the space below, use the information from the website to summarize the ideal climatic conditions for sugar maple tree growth.




  4. From what you described in #2 above, is maple syrup production possible in the entire range of the maple tree?  Explain.





  5. What do you think would happen to the range of the maple tree should the climate within the range warm?




  6. Assuming the climate does warm, what do you think will happen to maple syrup production?





(We will look at the above two questions again at the end of this lesson after exploring some data.)


Part II: Climate in a Maple Syrup State


Now that you know about maple syrup production and about the geographic range of the maple tree, let's look at local and regional weather and climate conditions to identify the difference between a productive maple syrup season and an unproductive maple syrup season.  First, let's look at climate which includes data averaged over 30 years.  The graph in Figure 2 is called a climatograph.  Study it for a few minutes and then answer the questions below.


Figure 2: Climatograph for Burlington, VT.  (Data from

  1. From the climatograph above and your knowledge of maple syrup production, which       month(s) is(are) ideal for collecting sap?



    Why did you select those months?




  2. The climatograph in Figure 2 gives you the 30-year average temperature and      precipitation data for Burlington.  However, it does not tell you if your choices for           the question above are accurate for every year within that 30-year period, nor does it tell you how many days were available to collect sap during each year.  For that you will need a more detailed picture of the weather and climate over that time period.  Go to's Daily Average page for Burlington, VT.  Based on the required temperature conditions necessary to collect sap from maple trees, count the approximate number of days available to collect sap for each of the following months (use Average High and Low temperatures listed).  Start counting where the maximum temperature is 40°F or higher and the minimum temperature is below freezing. What is the total number of days available to collect sap based on these averages?


    March:             ____________________


    April:               ____________________


    Total:             ____________________



  3. Based on the data above, how important is the daily temperature to the maple sugar industry?  Do you think the total above has been the same for every year of the data record? Explain.







  4. Does snow cover extend or shorten the sap collecting season?






    From your research into the conditions necessary for sap to run, what happens when the temperatures remain too high for an extended period of time in April?  How does this affect the flavor of maple syrup from the collected sap?


  5. Let's look a little closer at the number of days that were available to collect sap in Burlington, VT from 2002-2010.  Go the Weather Underground Weather History pagefor Burlington, VT and scroll down to the calendar and count the actual number of days that were available to collect sap for that year.  Place your data in the table provided. Use the links at the top of calendar to change the years and months. In the last column calculate the difference in the total number of sap collecting days using the data from Question #2 above. Put a (+) in front of the number if the number of days was greater, and a (-) in front of the number if it was less.


    Possible Number of Maple Sap Collecting Days


    Days in March

    Days in April

    Total Days for that Year

    Difference (+ or -) from the average total found in Ques. #2 above















































    How do the numbers compare with the numbers you found in Question #2?  Explain.




    What else should you consider when comparing the climate and weather for Burlington, VT, in relationship to the number of available days to collect sap? (Hint: look at your response to question #4 above.)








    Part III: How Do the Numbers Compare with Maple Sugar Production?


    In the above parts of the lesson you correlated daily temperature with the temperature conditions necessary for sap to run in a maple tree and determined the number of days available each year to collect sap.  Now we will look at maple syrup production for those years to see how production numbers compare with temperature.


    Vermont Maple Syrup: Taps, Yield, and Production for 2002-2010

    (Data is from the National Agricultural Statistics Service of the U.S. Department of Agriculture)


    Number of Taps

    (x 1000)

    Yield per tap



    (x 1000 gallons)






































    1. The maple syrup table above includes the number of taps, the yield per tap and the  entire annual production for the time period of 2002-2010.  To correlate the temperature data with production we need to choose the appropriate data from the table. We know that there would be a good chance that production will increase with the number of taps. However, the yield per tap will be climate dependent, and therefore we will use the yield per tap in our comparison.  Use a piece of graph paper to create a graph with 2 vertical axes. On the horizontal axis, place the year, and on the left vertical axis, place the total days of sap collection (from question #5 above).  On the right vertical axis, place the yield per tap in gallon.  Plot one line at a time.  Be sure to spread the data out on your graph so that correlating your data will be easier.


    2. Does your graph model a relationship between the two data sets (number of days of production and yield)?  Explain.





      What additional information would you collect before you draw any conclusions about the relationship between daily temperature and maple syrup production?  Explain why.








    Part IV: Maple Syrup Production in the Past and into the Future

    In Part I of this lesson you explored the range of the sugar maple.  In this part of the lesson, we will explore how this range and possible production locations have changed over geologic time (maple sugaring does have a very long history, but it’s not safe to assume that maple syrup has been produced throughout all of geologic time!).


    1. The pollen viewer incorporates fossil pollen data to create maps of the ranges for selected trees.  The default genus and species for the viewer is Picea.  We will need to change this to Maple by changing the "Nomenclature" to "Common" and selecting "Maple" from the dropdown menu at the top of the viewer.  Play the animation numerous times to observe the changes in the population and range of the maple tree. Clicking on the play button will allow you to stop and start the animation.


    2. Find out the dates and ranges for the last ice age by searching online or by looking in a reference book. Describe the migration of the maple tree after North America came out of the ice age (look at the dates of the final retreat of the glacier that blanketed North America during the ice age).





    3. Using your knowledge gained from other parts of this lesson, what does this tell you about the climate conditions in North America over the time period portrayed in the Pollen Viewer?






    4. Utilizing what you know about the climate necessary for sap to run in maple trees, how has the location of this given climate changed over the time period portrayed in the Pollen Viewer?






    5. Le's take a look into the future to see what climate models are predicting the impact of climate change on the range of the sugar maple tree will be. Open the Climate Change Atlas for 134 Forest Tree Species of the Eastern United States and click on the column header "Common Name" to arrange the tree species in alphabetical order.  Scroll down to sugar maple.  What does the green dot next to the name indicate?




    6. Click on "sugar maple" to bring up the data output options for this tree species.  Click on             "Abundance Change Maps" under "Modeled Future Habitat" in the right set of choices. To evaluate the habitat of the sugar maple for the year 2100, change the climate scenario to "Avg. of 3 - High" by clicking on the Climate Scenario pull down menu.  The colors in the legend refer to the species importance value for the particular habitat of that species. Compare this value on both maps for the state of Vermont.  How does the importance of this habitat change over this model period?





      How will this change impact maple syrup production in the future?






    Our original question asked how climate change will affect crop production and more specifically how it will affect maple syrup production and your breakfast. Throughout this investigation you gathered and analyzed weather data, climate data, and production data.  From all this data, what can you conclude about maple syrup production in the short term (next 20 years) and in the long term (up to the year 2100)?  In your conclusion, explain the role of annual temperature variability in the production of maple syrup and the role future trends in temperature will have on the production of maple syrup. Use a separate piece of paper for your response.




    What crops do you think will be more susceptible to the negative impacts of climate change?  Why?  Use the resources from this lesson as well as Quick Stats 1.0 from the United States Department of Agriculture National Agricultural Statistics Service to locate additional information.  Focus on one crop that is important to what you eat for breakfast. Use a separate piece of paper to report your findings, and be prepared to share your results with your classmates.








    Citation for the Change Atlas for 134 Forest Tree Species used in Part IV:

    Prasad, A. M., L. R. Iverson., S. Matthews., M. Peters. 2007-ongoing. A Climate Change Atlas for 134 Forest Tree Species of the Eastern United States [database]., Northern Research Station, USDA Forest Service, Delaware, Ohio.


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