Have stump piles any effect on the pine weevil (Hylobius abietis L.) incidence and seedling damage?

Tree stumps are being increasingly used for bioenergy purposes, which may have significant effects on pine weevil (Hylobius abietis L.) populations and the level of damage they can cause to seedlings. Pine weevils are attracted by the smell of fresh stumps in clear-cut areas, and have been shown to cause serious damage to planted coniferous seedlings in European forests. This study was conducted to measure the incidence of pine weevil and damage caused to Norway spruce (Picea abies) seedlings in a field experiment including single stump pile plots (SSP), multiple stump pile plots (MSP) and control plots in North Karelia, Finland. Pine weevils were significantly more abundant in MSP stump plots (22% higher) than in SSP plots, and are 23% more abundant compared to the control plots. The extent of seedling damage was significantly lower in the SSP (by 67%) and MSP plots (by 58%) than in the controls. Seedlings damage increased significantly with the distance from the stump pile. Stump harvesting practices should be updated and, in particular, multiple stump piles should be avoided in the clearcut area. However, future studies will be required to explore the environmental and physical factors in the stump-removal area influencing pine weevil abundance.