The declivity at the end of the wing covers is steep, very shallowly bisulcate, and at the apex it is generally flattened with small granules.

[1] In later stages of decline, beetle entrance holes and galleries were found scattered every 2 to 5 centimeters, essentially crippling the tree.

[3] A similar instance occurred during this same time period in Delta, a city nearly four hundred kilometers west of Denver.

[3] Bark beetles are a major natural disturbance in North American forests, in recent history affecting more area annually than fire does.

[5] Human intervention in disturbances related to tree extinction because of infectious disease or invasive wildlife has historically been costly and therefore limited at best.

[7] Bark beetles usually feast on limbs no greater than 10 centimetres (3.9 inches) in diameter, spreading Dutch elm disease to a place that is still manageable to prune.

Community officials claim that the best thing people can do is not transport firewood, limiting the human spread of the disease.