thumb|Nail sunk into a birch in Sweden.
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 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" by logging industry advocates.
History
It was first mentioned in the context of discouraging logging in Earth First! magazine.
Pat O'Dea, while he was the mayor for the Buller District, suggested in 2000 that Native Forest Action (NFA) had spiked trees during a direct action campaign against native forest logging on the West Coast. This was denied by NFA spokesperson Dean Bagient-Mercer. In 1998, Kevin Smith from Forest and Bird had said that tree spiking was proposed by some individuals involved in the NFA campaign. and was passed into federal law as an amendment, introduced by senators James A. McClure and Mark Hatfield, In 1993, John Blount and others were convicted under this statute for spiking trees in the Clearwater National Forest, after Tracy Stone-Manning agreed to testify in exchange for immunity from prosecution. In 2021, President Biden nominated Tracy Stone-Manning to lead the Bureau of Land Management. Leading up to her confirmation, significant press attention was given to allegations that she was a central member in the 1989 tree-spiking plot.
In 1990, Earth First! leaders, including Judi Bari and Mike Roselle, issued a memo and press release to Earth First! activists in Northern California and Southern Oregon, renouncing tree-spiking as a tactic on the eve of Redwood Summer, a 1990 campaign of nonviolent protests against logging of the redwood forest.