Can Trees Get Cancer?

This tree developed a mutation that caused a growth called a “burl.”

Possible Guiding, Compelling and/or Anchoring Questions

• What is this on the side of the tree? Is it supposed to be there?
• Is this considered cancer? How is it different from humans?
• What caused the tree to develop this defect?
• What don’t we understand about these burls?
• Should we be allowed to harvest burls for woodworking?

Classroom Suggestions

• Start off this lesson by simply showing the picture of the tree with a burl. This will be clear to students that something is wrong with the tree. From here you have a natural progression from learning what cancer is to what caused this to happen? 
• The latter will be addressing the standard, but having a brief understanding of what cancer is will help increase their understanding about what is going on. To do this, I recommend the readings attached below. They go over all the details you will need to know. 
• “In burl formation, the tree’s growth hormones get disrupted when the metabolism of the tree is hijacked by some other organism – a virus, fungus, or bacterium.” Some of this bacterium even carries extra DNA to infect the tree. Other sources below indicate it can form when a tree gets damaged and callus tissue develops, folding over on itself. Either way this is a genetic phenomenon that alters how the tree grows. It is not all bad though. Because plant cells have cell walls, this mutation does not spread. It only grows. In addition this genetic trait/alteration has helped trees survive from less-ideal environmental factors, because If the tree then dies, a new tree can sprout from the burl. 

Related Resources

• Can Trees Get Cancer?: Utah State University explained four different types of mutations trees can get. Then it goes into detail how these mutations are different for trees compared to humans.
• Can Plants Get Cancer?: This article has student-friendly language about potential causes of tree cancer. 
• What Is a Burl?: This gives a more thorough overview on burls, and will most likely answer most of the questions students would have over them.
• Go Figure: How Tree Burls Grow: This article goes more in depth on what exactly causes the burl. It also explains why they are cherished by woodworkers.