Summary

Chapter 25

A tree can get sick if it puts too much energy into growing and therefore neglects its self-defense. They have defensive antibiotic compounds and compounds to ward off insects for a large area around them. When a gap opens up in the canopy, many trees seize the opportunity to make a growth spurt but thereby risk an attack by fungi or insects. In Switzerland, some exceptional trees were found to have been attacked by a fungus that killed their cambium, but the roots continued to pump water into the needles and their neighbors must have supplied them with nutrition. A tree can also be injured when a neighbor falls and breaks its bark, leaving it vulnerable. The tree tries to grow new wood over the opening, but a fungus may simultaneously be trying to get a hold. In the outer layers, the...