The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World

Wohlleben explains that trees use energy to grow, and store energy in reserve so they can react promptly when insects or illnesses attack. They also must save energy for reproduction and propagation when the appropriate time of year arrives. Wohlleben explains that trees are particularly vulnerable to insect damage after they bloom. He attributes this to their low energy levels; they expend so much energy producing their blossoms that they cannot use any more to activate their chemical defenses against the insects. He notes that healthy trees will overcome this difficult part of the year, while weaker trees will die from it.

Observing trees’ blossom and nut production is not a reliable way to predict future weather patterns, since they actually reveal the recent conditions the trees have lived through. This is because trees’ blossoms are formed, and then remain dormant, throughout the previous year. Wohlleben explains that trees that are sick or dying often produce a great amount of blossoms more quickly than their neighbors in order to maximize the likelihood they will successfully reproduce before they die.

Wohlleben expands his explanations about tree reproduction in his discussion of trees’ different propagation strategies. He offers the example of beechnuts and oak acorns, which sprout immediately after falling on soil that is moist and soft, in warm spring temperatures, while other seeds can live in the soil for months or years before sprouting.