tree spikes

Tree spiking involves hammering a metal rod, nail or other material into a tree trunk, either inserting it at the base of the trunk where a logger might be expected to cut into the tree, or higher up where it would affect the sawmill later processing the wood. Contact with the spike often damages saw blades, which can result in injuries, or death, to nearby workers. The spike can also lower the commercial value of the wood by causing discoloration, reducing the economic viability of logging in the long term, without threatening the life of the tree. It is illegal in the United States, and has been described as a form of eco-terrorism.