What effect can a bark beetle infestation have on forests?

A bark beetle infestation can lead to widespread tree death and damage, significantly impacting forest ecosystems. When bark beetles invade trees, they burrow underneath the bark and feed on the inner phloem layer, which is vital for transporting nutrients and water within the tree. This activity disrupts the tree's ability to sustain itself, often resulting in the tree's decline or death.

The death of large numbers of trees can have cascading effects on the ecosystem, including alterations in habitat for wildlife, changes in microclimate, and increased risk of soil erosion. Furthermore, dead or dying trees can affect forest structure, potentially making way for invasive species to establish themselves and altering the species composition of the forest.

In contrast, options suggesting that bark beetle infestations promote healthy growth, have no effect, or enhance genetic diversity do not align with the ecological consequences typically associated with these infestations. Rather than fostering growth or genetic diversity, the primary outcome of an infestation is extensive tree mortality, which disrupts the balance and health of the forest ecosystem.