Ecological restoration of boreal low-productive pine forests

Aim: To assess the potential of ecological restoration of low-productive pine forests for the conservation of biodiversity associated with Scots pine.

Project description: The biodiversity of Swedish pine forests has changed drastically due to forestry and fire suppression. A considerable portion of Swedish pine forests grow in low-productive areas and timber was earlier extracted from these. This harvest successively declined and c 25 years ago forestry in low-productive areas was prohibited by law. Recreation of lost habitats, mainly dead wood, in low-productive pine forests (LPPFs) would therefore not reduce current timber harvest. Ecological restoration of these open and slow-growing forests would, most likely, benefit conservation greatly, because many species associated with slow-grown and sun-exposed pine/pine deadwood have declined drastically.

In this research project we explore these potential benefits and simultaneously address fundamental scientific questions about how microclimate, wood growth rate and wood position influence deadwood biodiversity. In an experiment we kill (girdle) and injure (scar) standing pines in LPPFs. We compare the response of beetle assemblages to this treatment between dry and wet LPPFs as well as with the responses in earlier experiments in more productive sites. In a longer-term study, we compare wood-inhabiting beetle and fungal assemblages in pines killed by fire 5-15 years ago between low-productive and more productive pine forests. This study evaluates the conservation effects of prescribed burning of LPPFs. In a third study, we analyze changes in abundance of deadwood etc. since 1950 in LPPFs using data from the Swedish National Forest Inventory, to get insight into how rapidly natural structures in LPPFs are restored in the absence of active restoration