The ancient Hebrews, it seems, used stoning to execute criminals because of the "almost treeless environment of Judea and Samaria".
In ancient Rome, deforestation apparently forced the Romans to recycle:
Still, in the semi-arid Mediterranean, the Romans, who suffered from the consequences of severe deforestation, conserved good quality timber by the practice of crucifixion. They used wooden crosses repeatedly, and even forced the condemned people to carry the horizontal beam. An alternative tree-based method that saved the trees used in execution was to bend two trees till they were close and tie them with ropes so the ropes prevented them from straightening up. The condemned person was tied to the trees (an arm and a leg to each tree), the ropes holding the trees were cut. The end was quick, and again there was no waste of timber.In the 18th century, the French were naturally at the cutting edge of green execution technology:
In then-wooded Medieval Europe, people were executed for centuries by the auto-de-fe, i.e. burnt alive on the stake. This spectacular procedure was carried on till the increasing depletion of the forests was recognized. Thus, in the 18th century, a new method, much friendlier to the environment, emerged: the guillotine. Taking into account the large number of people executed using the guillotine during the French Revolution, the continued use of the auto-de-fe would probably have depleted the remaining forests of Western Europe.Not to mention the fact that executing all those criminals must have reduced France's carbon footprint considerably. I'm sure Al Gore would have approved had he been around.