Future of the Forest

Part A: Migration of the Trees

Now that you have looked at past climate indicators, including plant pollen records, and have developed a sense of climate modeling and projected temperature increases, you will put the two together and consider the future of plants in a changing climate.

Plants, including trees, do not truly migrate, rather they disperse their seeds, which, given optimal growing conditions, can take root in new locations. This form of migration is slow, and limited by natural variability such as the wind direction or other transport mechanisms such as birds. The question many plant biologists have is whether or not the plants will be able to adapt or move as rapidly as needed to survive in the changing climate.

Get a sense how much the temperature may increase

First, go to the NOAA Data Snapshots and select the Projections showing the United States.

Next, click Average Temp - High Emissions. Then use the sliders below the map to set the year 2050, and the scroll through the months. To learn more about this snapshot click the words read more in the About this Snapshot box.

Once you have observed the changes in the time period 2050, change the time period to the 2080s.

Finally, zoom in for a local view of climate change, by going to the NOAA Climate Explorer to view the trends in temperature since 1950, in Burlington VT, the home of the maple tree featured in the case study. Look at the trends in temperature since 1950, as well as the predicted change in temperature in the future. Use the graph, legend, the sliders, and data on the Climate Explorer page to answer the Checking In questions, below.

Checking In

  1. What has been the trend in the average daily max temperature (˚F) since 1950? How many degrees of change in the past 70 years (1950 -2020)?
    [INCORRECT]Hint: Use the slider to move the graph data towards the axis.
  2. What is the trend in Days w/ min <32 ˚F? How many fewer "frost days" are predicted to occur in the year 2090 than in 1950?
    [INCORRECT]Hint: Use the sliders to adjust the years. Subtract the present number of days from the future number of days.
  3. Compare the higher and lower emission scenarios. Using the red and blue line, determine how many more days with a max >90˚F will occur in the year 2080 in the higher emission scenario in contrast to the lower emission scenario ?
    [INCORRECT]Hint: Use the sliders to adjust the years. Subtract the present number of days from the future number of days.

Consider the changes in your own home region

Use one of the tools introduced on this page to zoom into your home state, region, or city, and see the past and predicted future changes in temperature. You can also change the map type to precipitation and explore the changes in precipitation in your hometown, across the United States, or globally.


Put climate change in perspective by considering the following:

How old will you be in 2050, 2080, 2090? 
How much will the temperature in most of the United States have changed by 2080? 
Give several examples of how the increase in average temperature or precipitation could impact your daily life. 
How will changes in days above 90˚F impact your life? 
How will frost free days impact the maple sap flow?

Learn more about the needs of the sugar maple (Acer Saccharum) tree

Now that you have seen the changes in temperature for this time period, recall the needs of the sugar maple by reading this page Silva Culture Information – Maple Sugar tree. Use the information in the publication to answer the Stop and Think questions below.

Stop and Think

  1. What is the native range of the sugar maple? (see the map in the article)
  2. According to the publication, what is the optimum temperature for germination? Scroll down the page to where it discusses germination, under the heading "Seed Production and Dissemination," to find this information.
  3. What happened to the Maple seed crop in Wisconsin in the winter and spring of 1977-1978?
  4. Based on the outcome of this event, what do you predict will happen to the germination success for trees in the next 40-70 years?

Migration of the trees

Next, view the graphic, below, from U.S. Climate Program office (globalchange.gov) showing the distribution of tree species in the recent past and in the projected future. Find the Maple-Beech-Birch forest in the graphic.

Checking In

  1. What color is used to represent Maple-Beech-Birch forest?
  2. What has happens to the range of these tree species during the 100-year time interval between the two graphics? Check all that apply.
  3. What type of forest replaces the Maple-Beech-Birch forest?
    [CORRECT] Generally, the Maple-Beech-Birch forest is replaced by Oak-Hickory and also by Elm-Ash-Cottonwood.

After you have viewed the change for the entire eastern United States, examine the trees of the Northeast featured in the graphic below. The species are again color-coded. Note the present location and the potential future locations under each of the two emissions scenarios. What happens to the range of the sugar maple (and Maple-Beech-Birch forest) in each case?

Investigate tree migration with the U.S. Forest Service's Tree Atlas

Investigate the potential changes in tree (and bird) habitat using the U.S. Forest Service's Climate Change Atlas. On the Atlas homepage, read the introductory paragraph, describing the Atlas, and then access the interactive Atlas website either from the homepage or by clicking this link: U.S. Forest Service's Tree Atlas

Once there, choose a tree species of interest, either by common name or by scientific name. On the next page that opens, click the button Abundance Change Maps, under Modeled Future Habitat. Select the Average of 3 GCM's - High to compare with the current FIA (Forest Inventory Analysis). On the maps, the color key shows the abundance of the tree species while the blue line is the boundary of the potential range of the species. Explore several species of interest, including the sugar maple.

Generalize to other plants

Go to the Updated Hardiness Zone Map image and observe the graphic that shows the USDA plant hardiness zones in 1990 and 2012.

Stop and Think

5. Now that you have explored climate factors, explain how climate zones are used to make hardiness zone maps and why the USDA revised the hardiness zone map in 2012 or 2015. How do you think climate change will change the types of plants growing in your neighborhood? 

6. What types of impacts could a change in the tree species have on other life in the forest, for example, insects or birds?

How do we know what we know?

What do trees and bees have in common? Pollen. NASA satellites have observed a change in the timing of spring "green-up" over the past few decades indicating a warmer climate. In order to confirm the change in plant life, scientists such as Wayne Esaias, are now studying changes in the timing of honey bee honey production.

Watch this short NASA video (5 minutes) and read more about scientists are studying climate change and its impact on plants, pollen, and honey bees.

Honey Bees Turned Data Collectors Help Scientists Understand Climate Change

Feeling the Sting of Climate Change - Source: NASA

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