Wohlleben explores how trees can “travel” by producing seeds capable of being carried by the wind. He explains that there is an evolutionary tradeoff for seeds that are light enough to be airborne. Trees such as poplars and willows have evolved tiny, lightweight seeds with hairs that help them float on the wind for long distances. However this prevents them from being able to contain nutritional “provisions” within their seeds and so they are more vulnerable to dying of hunger or thirst (186). The author contrasts this with seeds from birch, maple, and hornbeam trees which are too laden with these provisions to fly on the wind, and so they equip their seeds for flight in a different way. Wohlleben explains that these tree species have evolved wing-like features that, if caught in a breeze, have the potential to travel for up to a mile. Wohlleben explains that pioneer species with seeds that can fly are excellent at colonizing new areas, even after natural disasters such as volcanic eruptions.

The author continues by describing how the heaviest tree seeds, such as oak acorns and chestnuts, cannot be carried by the wind at all. Wohlleben argues that this is why these seeds “enter into an alliance with the animal world” (187).