Oaks in many forests!
Mixed forests with large oaks (Quercus spp.) and high conservation values are scattered throughout the Holarctic temperate zone, from Asia to Europe to North America. In Sweden there are at least 30 000 such forests south of "Limes Norrlandicus", the biologically quite welldefined border separating the boreal forest from the temperate (or cold temperate) forest in our country. These forests are pleasant to stroll through and have a rich diversity of animals, plants and fungi – many of the species are relatively rare, since coniferous forests, and forestry, with Norway spruce and Scots pine dominate in Sweden. Some mixed forests with oaks are used for timber harvesting, some have been left to develop without any intervention by the forest owner (who may not need to harvest), many have been defined as "woodland key habitats" by the Swedish Forest Agency (more than 20 000 mixed oak forests), and some are protected in the form of national parks, nature reserves, biotope protection areas, or through conservation agreements or deals between the forest owner and the government. In Götaland in the south of Sweden, the Oak Project has studied 25 such "conservation forests" for more than 20 years (forests more or less protected for biodiversity purposes, and for research).
Aims and focus
The Swedish Oak Project at the University of Gothenburg started in the spring of 2000 and is a longterm research project aiming to improve our understanding of how oakrich mixed forests function and can be managed for (primarily) conservation purposes and biological diversity. Many oakrich mixed forests, and almost all our "noble" (hardwood) broadleaved forests developed from an older, more open, traditional agricultural landscape, where several special species thrived but are now declining. Active management measures to create more open forests are hence motivated, but need to be evaluated – a crucial point, which calls for an experimental approach. Oaks do well in more open habitats, and especially small oaks grow better under such circumstances. But "to manage" also includes what we call minimal intervention, in forests of high conservation value consider the oldgrowth forests, where nature and time has created living space for many species which currently cannot live in managed production forests (or whose populations are strongly reduced there).
Our concept conservation thinning is a management measure developed over 16 years and onwards an evaluation that requires a lot of planning, effort, and long time periods, as trees grow slowly and can grow much older than humans. A number of councils and foundations have supported the Swedish Oak Project over the years, including the Swedish Research Council (VR), FORMAS, and the Swedish Energy Agency (among other things we have evaluated careful harvesting of biofuel).