Tree spiking is a form of sabotage which involves hammering a metal ro or other material (commonly ceramic) into a tree trunk in order to discourage logging. A metal saw blade hitting an embedded spike could break or shatter, making it uneconomic to use those trees. Spikes could possibly injure or kill loggers. It is often referred to by critics as a form of Eco-terrorism. However metal objects unrelated to tree spikes are also not uncommon to find in trees, objects such as nails or gun shot can be lodged in a tree without intention.