- Maria Forsberg (1)
- Marina Gurskaya (1)
- Joakim Hjältén (1)
- David J. Mladenoff (1)
- Risto Jalkanen (1)
- Johnny Jong de (1)
- Vladimir Kukarskih (1)
- Jelena Lange (1)
- Therese Löfroth (1)
- Gabriel Michanek (1)
- Anouschka R. Hof (3)
- Jörgen Rudolphi (2)
- Martin Wilmking (1)
- Jeong Wook Seo (1)
- Timothy Work (1)
- Astrid Zabel (1)
Climate regimes override micro-site effects on the summer temperature signal of scots pine at its northern distribution limits
Lange, Jelena ; Buras, Allan ; Cruz-García, Roberto ; Gurskaya, Marina ; Jalkanen, Risto ; Kukarskih, Vladimir ; Seo, Jeong Wook ; Wilmking, Martin - \ 2018
Frontiers in Plant Science 871 (2018). - ISSN 1664-462X
Boreal forest - Climate change - Climate regime - Maximum latewood density - Micro-site - Pinus sylvestris - Tree-ring width - Treeline
Tree growth at northern boreal treelines is generally limited by summer temperature, hence tree rings serve as natural archives of past climatic conditions. However, there is increasing evidence that a changing summer climate as well as certain micro-site conditions can lead to a weakening or loss of the summer temperature signal in trees growing in treeline environments. This phenomenon poses a challenge to all applications relying on stable temperature-growth relationships such as temperature reconstructions and dynamic vegetation models. We tested the effect of differing ecological and climatological conditions on the summer temperature signal of Scots pine at its northern distribution limits by analyzing twelve sites distributed along a 2200 km gradient from Finland to Western Siberia (Russia). Two frequently used proxies in dendroclimatology, ring width and maximum latewood density, were correlated with summer temperature for the period 1901–2013 separately for (i) dry vs. wet micro-sites and (ii) years with dry/warm vs. wet/cold climate regimes prevailing during the growing season. Differing climate regimes significantly affected the temperature signal of Scots pine at about half of our sites: While correlations were stronger in wet/cold than in dry/warm years at most sites located in Russia, differing climate regimes had only little effect at Finnish sites. Both tree-ring proxies were affected in a similar way. Interestingly, micro-site differences significantly affected absolute tree growth, but had only minor effects on the climatic signal at our sites. We conclude that, despite the treeline-proximal location, growth-limiting conditions seem to be exceeded in dry/warm years at most Russian sites, leading to a weakening or loss of the summer temperature signal in Scots pine here. With projected temperature increase, unstable summer temperature signals in Scots pine tree rings might become more frequent, possibly affecting dendroclimatological applications and related fields.
Simulating long-term effects of bioenergy extraction on dead wood availability at a landscape scale in Sweden
Hof, Anouschka R. ; Löfroth, Therese ; Rudolphi, Jörgen ; Work, Timothy ; Hjältén, Joakim - \ 2018
Forests 9 (2018)8. - ISSN 1999-4907
Biodiversity - Biofuel - Boreal forest - Modelling - Saproxylic species
Wood bioenergy may decrease the reliance on fossil carbon and mitigate anticipated increases in temperature. However, increased use of wood bioenergy may have large impacts on forest biodiversity primarily through the loss of dead wood habitats. We evaluated both the large-scale and long-term effects of different bioenergy extraction scenarios on the availability of dead wood and the suitability of the resulting habitat for saproxylic species, using a spatially explicit forest landscape simulation framework applied in the Swedish boreal forest. We demonstrate that bioenergy extraction scenarios, differing in the level of removal of biomass, can have significant effects on dead wood volumes. Although all of the scenarios led to decreasing levels of dead wood, the scenario aimed at species conservation led to highest volumes of dead wood (about 10 m3 ha-1) and highest connectivity of dead wood patches (mean proximity index of 78), whilst the scenario aimed at reaching zero fossil fuel targets led to the lowest levels (about 8 m3 ha-1) and least connectivity (mean proximity index of 7). Our simulations stress that further exploitation of dead wood from sites where volumes are already below suggested habitat thresholds for saproxylic species will very likely have further negative effects on dead wood dependent species.
Landscape planning-paving theway for effective conservation of forest biodiversity and a diverse forestry?
Michanek, Gabriel ; Bostedt, Göran ; Ekvall, Hans ; Forsberg, Maria ; Hof, Anouschka R. ; Jong, Johnny de; Rudolphi, Jörgen ; Zabel, Astrid - \ 2018
Forests 9 (2018)9. - ISSN 1999-4907
Aichi targets - Biodiversity - Birds directive - Boreal forest - Compensation - Fragmentation - Habitat protection - Habitats directive - Landscape planning - Tax-fund
Globally, intensive forestry has led to habitat degradation and fragmentation of the forest landscape. Taking Sweden as an example, this development is contradictory to international commitments, EU obligations, and to the fulfillment of the Parliament's environmental quality objective "Living Forests", which according to Naturvårdsverket (The Swedish Environmental Protection Agency) will not be achieved in 2020 as stipulated. One important reason for the implementation deficit is the fragmented forestry management. In a forest landscape, felling and other measures are conducted at different times on separate forest stands (often relatively small units) by different operators. Consequently, the authorities take case by case decisions on felling restrictions for conservation purposes. In contrast, conservation biology research indicates a need for a broad geographical and strategical approach in order to, in good time, select the most appropriate habitats for conservation and to provide for a functioning connectivity between different habitats. In line with the EU Commission, we argue that landscape forestry planning could be a useful instrument to achieve ecological functionality in a large area. Landscape planning may also contribute to the fulfilment of Sweden's climate and energy policy, by indicating forest areas with insignificant conservation values, where intensive forestry may be performed for biomass production etc. Forest owners should be involved in the planning and would, under certain circumstances, be entitled to compensation. As state resources for providing compensation are scarce, an alternative could be to introduce a tax-fund system within the forestry sector. Such a system may open for voluntary agreements between forest owners for the protection of habitats within a large area.
Climate change mitigation through adaptation : The effectiveness of forest diversification by novel tree planting regimes
Hof, Anouschka R. ; Dymond, Caren C. ; Mladenoff, David J. - \ 2017
Ecosphere 8 (2017)11. - ISSN 2150-8925
Assisted migration - Boreal forest - Carbon stocks - Climate change - Ecosystem services - Forestry - Modeling - Temperate forest
Climate change is projected to have negative implications for forest ecosystems and their dependent communities and industries. Adaptation studies of forestry practices have focused on maintaining the provisioning of ecosystem services; however, those practices may have implications for climate change mitigation as well by increasing biological sinks or reducing emissions. Assessments of the effectiveness of adaptation strategies to mitigate climate change are therefore needed; however, they have not been done for the world’s northern coniferous forests. Diversifying the forest by planting tree species more likely suited to a future climate is a potential adaptation strategy to increase resilience. The efficacy of this strategy to reduce the risks of climate change is uncertain, and other ecosystem services provided by the forest are also likely to be affected. We used a spatially explicit forest landscape modeling framework (LANDIS-II) to simulate the effects of planting a range of native tree species in colder areas than where they are currently planted in a managed temperate coniferous forest landscape in British Columbia, Canada. We investigated impacts on carbon pools, fluxes, tree species diversity, and harvest levels under different climate scenarios for 100 yr (2015–2115) and found that the capacity of our forest landscape to sequester carbon would largely depend on the precipitation rates in the future, rather than on temperature. We further found that, irrespective of the climate prediction model, current planting standards led to relatively low levels of resilience as indicated by carbon fluxes and stocks, net primary productivity (NPP), and species diversity. In contrast, planting a mix of alternative tree species was generally superior in increasing the resilience indicators: carbon stocks and fluxes, NPP, and tree species diversity, but not harvest rates. The second best novel planting regime involved adding Pinus contorta to the stocking standard in three ecoregions; however, that species is susceptible to a high number of insects and pathogens. We conclude that although the capacity of temperate coniferous forest landscapes to sequester carbon in the future is largely dependent on the precipitation regime, negative effects may be counteracted to some extent by increasing resilience through tree species diversity in forests.