Classroom Questions

Questions for ‘Rampaging vines are slowly strangling tropical forests’

a photo of the base of a huge tree wrapped in multiple thick woody vines climbing up it and out of the image frame

Woody vines, called lianas, are increasing in tropical forests across South and Central America. Once they climb a tree, they rapidly spread their leaves over those of the tree, stealing the tree’s sunlight. Because of this and other traits, lianas slow the growth of trees — and can kill them.

Manfred Gottschalk/Stone/Getty Images Plus

By Science News Explores

To accompany ‘Rampaging vines are slowly strangling tropical forests’

SCIENCE

Before Reading:

  1. What is a parasite? Give two examples of parasites and their hosts.
  2. Different plants grow at different rates. Put the following plants in order from fastest growing to slowest: maple tree, dandelion, corn, rose bush. What are some general characteristics of plants that grow very quickly? What are general traits of those that grow more slowly?

During Reading:

  1. What signs of a lightning strike did Evan Gora find in the canopy on Barro Colorado Island?
  2. How can lianas change the effects of lightning in tropical forests?
  3. What does it mean to say that lianas are structural parasites? How does this affect their growth and internal structure?
  4. What are some defenses that trees have evolved against lianas? List at least three.
  5. How can lianas create gaps in forests? How might this change the local ecosystem?
  6. Why did people assume that lianas existed in balance with forest ecosystems? What did Oliver Phillips discover that challenged that assumption?
  7. In work by Stefan Schnitzer and Geertje van der Heijden, how did the growth rates of trees and lianas compare during the wet season? How did they compare during the dry season?
  8. What are three reasons that lianas may fare better than trees during dry times of the year?
  9. How did José Medina-Vega study seasonal changes in lianas and trees? What did he learn?
  10. In another study by Schnitzer and van der Heijden, how much did the presence of lianas reduce the amount of carbon dioxide absorbed by a forest?

After Reading:

  1. Lianas are described as having “fast and furious” growth compared to trees. Describe at least two benefits to this growth strategy, as discussed in the story. What are some possible tradeoffs for the lianas of relying on fast growth and other “cheap” traits? Now imagine that a population of lianas has expanded so much that the vines have pulled down all the trees in a region. What do you think will happen to the lianas?
  2. Given the effects of climate change on droughts and heat waves, would you expect liana growth to increase, decrease or stay the same relative to tree growth? Explain your answer. Over a long period of time, do you think lianas will ever fully overtake a forest? Why or why not?