Tree spiking involves hammering a metal rod, nail, or other material (commonly ceramic) into a tree trunk, strategically inserting it at the base of the trunk where a logger might be expected to cut into the tree. It is an unconventional tactic, used to discourage logging by creating a mantrap which may injure or kill lumberjacks who attempt to cut down the tree or mill workers who process the wood. Furthermore, the presence of the spike reduces the commercial value of the wood, thereby reducing the economic viability of logging in the long term, while not threatening the life of the tree.
It is believed that tree spiking originated in timber logging labor disputes in the Pacific Northwest of the United States in the late 19th century. It came to prominence as a contentious tactic within unconventional environmentalist circles during the 1980s, after it was advocated by Earth First! co-founder Dave Foreman in his book Ecodefense. In the book, he discusses how to do it and how to avoid risks to the activist and the logger.
One injury possibly from tree spiking occurred in the United States in 1987. California mill worker George Alexander was seriously injured when the bandsaw he was operating was shattered by either an old nail or a tree spike. This led many progressive Earth First! groups to denounce tree spiking. Other activists were led to either reject this form of sabotage entirely, or take some precautions, such as putting warning signs in the area where the trees are being spiked. Tree spiking is condemned by opponents of eco-terrorism as they claim it is potentially dangerous to loggers or mill-workers, although only this one injury possibly resulting from tree spiking has been widely reported.
 New Zealand
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.
 United States
In 1990, Earth First! leader Judi Bari led activists in Northern California and Southern Oregon to renounce tree-spiking as a tactic on the eve of Redwood Summer, a 1990 campaign of nonviolent protests against logging of the redwood forest.
 Tree spiking in fiction
Severed: Forest of the Dead: Anti-logging activists sabotage a tree by spiking it, breaking the blade on a logger’s chainsaw and cutting him. The genetically enhanced tree sap mixes with the logger’s blood, starting a chain reaction of zombie mayhem.
"Darkness Falls" (The X-Files): Two environmentalist "monkey wrenchers" are accused of spiking trees in a Washington state forest.
The Anarchist Cookbook: In this film the antagonist Johnny Black plans on spiking redwood trees in an attempt to prevent logging.
The comic series Concrete, by Paul Chadwick, dedicated a multi-part story called "Think Like a Mountain" to the subject of tree spiking.
In the young adult novel "Spirit of the Rainforest" by Eric Wilson, young protagonist Tom Austen takes part in a protest against logging a rainforest but the protest is broken when a more radical character spikes a tree, angering non violent protesters.
In the 1991 L. A. Law episode "Do the Spike Thing", a mill worker sues a logging company and a radical environmentalist group when he is injured by a saw blade that breaks upon striking a spike.
 See also
- Rowell, Andrew (1996). Green Backlash. Routledge. p. 153. ISBN 0-415-12828-5, 9780415128285 Check
- Ecoterrorism: The Dangerous Fringe of the Environmental Movement
- Nixon, Tina (1998-01-06). "Spikes put workers' lives at risk". The Southland Times.
- Madgwick, Paul (2000-04-14). "Public backlash around NZ feared". The Press.
- Bagient-Mercer, Dean (2000-04-27). "West Coast forests". Letter to the Editor (The Press).
- "Tree-spiking renunciation & Mississippi summer in the California redwoods"