Human transportation enabled a species of beetle to move from Asia to North America. This beetle feeds on a particular species of Powering trees. In its native habitat, predators control its population. However, the beetle has fewer predators
in North America,
A group of scientists studied the effect this beetle has on the tree population in the forest. After five years of research, they
determined that the beetle population doubled each year. On the other hand, the number of healthy trees decreased by
40 percent from the previous year's population. During the first year of their research, the scientists estimated that there
were 250 beetles and 4,000 healthy trees in the forest area.