" Giant hogweed is considered extremely dangerous because its sap, in combination with ultraviolet light, can burn human skin. Every year, millions are spent digging up plants and destroying them, without any great success. However, hogweed can spread only because the original forested meadows along the banks of rivers and streams no longer exist. If these forests were to return, it would be so dark under the forest canopy that hogweed would disappear. The same goes for Himalayan balsam and Japanese knotweed, which also grow on the riverbanks in the absence of the forests. Trees could solve the problem if people trying to improve things would only allow them to take over. "

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