Cross-scale perspectives on heterogeneity in Swedish boreal forests

Sammanfattning: Maintaining species diversity, ecosystem functioning, and socioeconomic values requires continued ecosystem heterogeneity across scales. This thesis aims to bridge gaps between ecological theory, environmental goals, and practical application of sustainable forest management needed to maintain such heterogeneity. Included case studies of boreal Sweden concern three challenges in the cross-scale understanding of heterogeneity: matrix qualities and composition; acquiring and incorporating historical information; and interactions between forest composition and management. Paper I cover three large-scale forest companies in four boreal counties today, outlining available information on matrix qualities and composition from the companies. Papers II-III cover the village scale from 1720s–1850s–present in Dalarna County and papers IV-V the parish scale from 1860s–present in the same county. Geographic Information Systems were used to integrate historical maps with present data, perform spatiotemporal analyses, and extract data for statistical testing in primarily generalized linear models. For the practical realization of sustainable forest management, the results indicate a need for further monitoring across scales to understand matrix composition, especially in relation to small voluntary reservations in a larger spatiotemporal perspective. Historical material can provide information on temporal connectivity and spatial separation between the past and present forest composition from analysis of change trajectories respectively interacting variables. This thesis suggests that models of forest dynamics are more relevant for local implementation of sustainable forest management efforts if including interactions between forest dynamics and ownership as an approximate driver of local change.