A mast year is a year in which vegetation produces a significant abundance of mast (fruit). The term originally applied solely to trees, like oak trees, that produce fruit useful for feeding farm animals. The term "mast" comes from the Old English word "mæst", meaning the nuts of forest trees that have accumulated on the ground, especially those used as food for fattening domestic pigs.[1]
More generally, Masting[2] describes not only abundance, but also paucity of fruit production, so masting is a group phenomenon that results when plants within a population synchronize their reproductive activity both in time and in size of crop.
Masting is the process whereby trees drop a large amount of seeds. This provides food for rats and stoats, whose populations can explode. In turn, this makes it more likely that birds will be targeted by the pests,[3] or that rats will invade nearby fields in what is called a rat flood.[4]