The phloem-yeast complex during infestations of the Mountain Pine Beetle in Lodgepole Pine

According to the most recent compilation of the timber resources of the United States of America, 1 insects, and particularly bark beetles, are credited with being the greatest killers of sawtimber trees. The report attributes 40 per cent of the mortality of sawtimber as well as 28 per cent of the mortality of growing stock to insects. Thus, in terms of outright kill, insects tar outrank any other tree destroyer.