Retrospective gap analysis in a Swedish boreal forest landscape using historical data

The main problem when adapting forest management to mimic natural processes and structures is the lack of detailed knowledge about historical forest c onditions. One way to refine these management goals is by local analysis of change in forest conditions over time. The aim of this investigation was t o perform a retrospective regional gap analysis by using historical data. F orest surveys and cadastral maps from the 19th and 20th century were compar ed with a recent forest survey in a 170 km(2) coniferous forest landscape i n the middle boreal zone of Sweden. Changes in species composition, age dis tribution and landscape pattern were analysed at different spatial scales u sing a GIS. Spatio-temporal analyses were made to compare representative fo rest types. During the 20th century, dear-cutting has replaced fire as the most important factor influencing the landscape pattern. The old-growth for est is fragmented and the proportion is much lower than in other boreal for est landscapes, Since the 19th century, the landscape has changed from a ma trix of forest older than 100 years to a highly fragmented landscape with o nly small patches of forest older than 100 years. Multi-aged stands have gr adually been converted to even-aged stands. The gap analysis indicates: a l arge deficit of multi-aged pine forest. Restoring this forest type requires large areas where Scots pine is allowed to naturally regenerate from seed trees on burned sites. Some trees need to grow to natural maturity (i.e. 20 0+ years) and die naturally. The restoration of deciduous forest should be directed towards mixed stands. Currently used models to describe the natura l landscape are inadequate to use as basis for ecological landscape plannin g. We conclude that retrospective gap analysis can be used to refine goal s etting in Swedish FSC-certification. (C) 2001 Elsevier Science B.V. All rig hts reserved.