Are bark beetles responsible for droughts in the Šumava Mts.? A mini-review

We attempt here to review recent studies focusing on droughts and hydrology in the Šumava Mts. The main question is can bark beetles affect water regimes in forest and what kind of measures might be taken – if any – to prevent bark beetle attacks. We compared results for natural forest, clear-cuts in managed forest and dead forest killed by a bark beetle attack. As expected, there was more water and a lower air temperature above the soil surface in natural forest. Dead trees shade undergrowth and so moderate temperature fluctuations. The conditions in clear-cuts are the worst for natural forest regeneration. There are no significant changes in the water cycle in catchment areas affected by bark beetle infections. However, it is predicted there is likely to be a slow decline in the amount of water due to a local change in climate, i.e. air temperature increase and precipitation decrease. It is concluded that droughts might occur more often and independently of bark beetle outbreaks in the future.