Along the banks of the Bóbr River in Bolesławiec, the effects of the beavers’ work can be seen—gnawed trees. Although some people may view such a sight as the result of “destructive activity,” beavers actually act very deliberately. These largest European rodents gnaw on trees for food, building materials, and their own safety.
Beavers do not eat wood in its entirety—they are interested in the bark, bast, and young shoots. Their favorite species are willows, poplars, aspens, and birches—trees growing near water are the easiest for them to access. Felled trees and branches serve beavers to build dams and lodges, and also help raise the water level, which increases the safety of their shelters. Higher water protects the entrances to lodges from predators and freezing in winter.
The rodents choose trees very deliberately. They usually gnaw on those growing within 10–20 meters of the water, prefer soft and medium-thick wood, and often fell trees so that they fall into the river themselves, making it easier to transport the material. Cutting down a thin tree takes them a few minutes, a medium-sized one several dozen minutes, and larger trees—even several hours, often with the cooperation of the entire family.
Beavers do most of their work at night, while the intensive feeding period falls in autumn, when they prepare supplies for winter, and in spring, when they repair dams after the thaw. In winter, they feed on branches and bark stored earlier, often under the ice.
Although beavers’ activities can sometimes be problematic for people—for example, flooding agricultural land—scientists emphasize that these rodents are extremely beneficial to the ecosystem. They create wetlands that become habitats for many other animals, improve biodiversity, and support natural water retention. Beavers therefore act as “engineers of nature,” transforming the landscape and providing themselves and other animals with a safe environment in which to live.