a) Monocultures of trees originally grown in higher altitudes with high water demands make it easy for the bark beetles to thrive (esp. in this warming climate).
b) Additionally, these monocultures usually lack multiple levels of vegetation, allowing wind to pass through (it should go over) and further drying the land, harming the trees and creating a favorable environment for the beetles.
c) We've deforested the countryside so that only small forest areas remain, with large clearings, enabling the wind in again. Thanks to this the forests are losing their ability to hold water and produce new rains, worsening the drought conditions.
d) The removal of dead wood and litter further exacerbates the drying and destroys biodiversity, making the conditions even more suitable for the bark beetles to infest.
e) Furthermore, we tend to prioritize the felling of the strongest and biggest trees, with deep roots, weakening the overall resilience of the forest.
f) Instead of letting the trees mature with deep roots, we cut down the plantations when they're only 40 years old (youngsters).
g) The spruce and pine monocultures are the most susceptible to destruction by beetles, and when they're felled and sold as round wood abroad, the cycle continues with the replanting of the same type of forest.