What do Douglas fir trees need to survive? How do birch trees help Douglas trees?<\/p>\n\n\n\n
As part of her forest growth research, Suzanne Simard tested how birch trees and Douglas fir trees affected one another. She found that eliminating birch trees actually hurt Douglas trees.<\/p>\n\n\n\n
Below we’ll look at Suzanne’s findings from her book Finding the Mother Tree<\/em>.<\/p>\n\n\n\n\n\n\n\n One experiment Simard conducted with the Forest Service involved a project to eliminate birch trees, which were perceived as competitors of the more valued Douglas fir trees (better known as either “Douglas trees” or “fir”). Again, Simard set out to show that there was likely some cooperation involved between the species. Her experiment results showed cooperation in two forms:<\/p>\n\n\n\n Let\u2019s look at the experiment to see how Simard reached these conclusions and how exactly that dynamic works between these two tree species.<\/p>\n\n\n\n In this experiment, Simard created companion plots and clear-cut plots, in the same way she had with the alder and pine. In one plot, the birch trees were completely removed, leaving the fir trees to grow in a monoculture; in another, the two were left to grow alongside one another, as they would naturally. Again, she found that killing the \u201ccompetitor\u201d birch didn\u2019t improve the growth of the cultivated Douglas trees, and in some cases it caused more of them to die\u2014<\/strong>in this case, the results were a result of carbon trading.<\/em> <\/p>\n\n\n\n Carbon trading:<\/strong> Carbon is an essential element of tree life, as trees convert it to sugars they need for energy. So Simard wanted to see if trees also share carbon with one another. During this experiment, she used chemistry techniques to measure relative amounts of carbon in the birch and fir trees across the growing season. She found that carbon was moving back and forth between the trees; the birch that were viewed as competitors of the fir were actually sharing carbon with them.<\/strong> And in fact, her measurements showed that the birch were giving more <\/em>than the fir were giving back. <\/p>\n\n\n\nBirch Contribute to Douglas Tree Health<\/strong><\/h2>\n\n\n\n
The Experiment and Results<\/h3>\n\n\n\n