Primary forests as indicators of global change and land use effects on carbon storage and greening trends

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<p>Forestry is a regionally dominant land use but the carbon and climate impact of boreal forest management is not well characterized, partly because no large-scale maps of managed and primary unmanaged forests exist. Northern land has greened considerably during the last decades and there is evidence of the growing dominance of the boreal biome in the global land sink of carbon. However it remains unclear what drives the observed changes, if it is management or environmental changes.</p><p>In this project we have mapped and classified the naturalness of more than 400 primary forests in Sweden. The primary forests are found from the temperate south to the boreal north of the country, and managed secondary forests are identified close to each primary forest forming spatial pairs of primary and secondary forests that share climate and landscape history but not management. The primary forests represent a natural baseline of ecosystem states and changes. Changes in these forests are driven by regional to global environmental change such as elevated CO2 concentrations, warming or nitrogen deposition. The managed forests on the other hand are influenced by both environmental changes and management. By studying the states and changes in the primary forests we can gain new knowledge in how ecosystems would have changed and what their states would have been with no management. By contrasting changes and states in the managed ecosystems we can estimate the long-term influence of management on both states and changes.</p><p>In this project the maps are used in combination with more than 100k forest inventory plots, extensive targeted field sampling over two years and remote sensing to understand, (i) changes in remotely sensed greening since 1984, and (ii) differences in carbon storage. We will present and discuss preliminary and more mature results that suggests that (i) primary forests have greened considerably since 1984, and at mature ages, faster than managed forests do, and (ii) store considerably more carbon than the paired managed forests do. </p>