A logging term known to have been in use in the United States from at least the early 1800's. If one had some very large logs to dispose of that were too large to chop, one would "nigger" them up into logging length by cutting a few notches on top of the log, at proper distances apart, and then build a fire on the log, lay a few poles across the log, and let them burn. One would then go around once or twice a day and stoke the "niggers" by knocking off the coals and laying more poles across the log. In three or four days the logs would be burn through or be "niggered off."
We decided to nigger the logs rather than wasting valuable time sectioning the fallen trees with axes.