Retrospective comparative analysis as a tool for ecological restoration: a case study in a Swedish boreal forest

Abstract

Summary Sweden’s boreal forest has experienced radical changes caused by humans since the beginning of industrialization. Ecological structures, such as large trees, dead trees and deciduous trees, have been removed from the forest. Natural processes, like fire, have been suppressed leading to ecosystem degradation, even in forest reserves. Many species that directly or indirectly depend on natural structures and processes are disfavoured and the need for restoration is evident. In this study, the status of a Swedish boreal forest is analysed in the context of biodiversity restoration. Based on ecological qualities of a historic reference state, a restoration gap analysis was produced. This gap analysis provides a method to view forest degradation and measure its deviation from the reference state. Ecological qualities are relatively high in the study area compared with the region, mainly because recent logging in the region did not greatly affect the study area. However, relative to the reference state, the area has lost significant ecological qualities due to earlier human activity. To be successful, strategies for restoring degraded forests should ultimately have landscape level approaches. Therefore, restoration of ecological qualities will not only include reserves but also production forests. In production forests, management strategies should be adapted to the natural functioning of the ecosystem. Consideration of restoration and management aspects during planning and formation of reserves will help ensure long-term species conservation goals. Methods to restore lost ecological qualities are discussed in the context of re-introducing fire and producing old-growth characteristics that predominated in the pre-industrial period.