@article{RiglingEilmannKoechlietal.2010, author = {Rigling, Andreas and Eilmann, Britta and Koechli, Roger and Dobbertin, Matthias}, title = {Mistletoe-induced crown degradation in Scots pine in a xeric environment}, volume = {30}, number = {7}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1758-4469 (Online)}, doi = {10.1093/treephys/tpq038}, pages = {845 -- 832}, year = {2010}, abstract = {Increasing Scots pine (Pinus sylvestris L.) mortality has been recently observed in the dry inner valleys of the European Alps. Besides drought, infection with pine mistletoe (Viscum album ssp. austriacum) seems to play an important role in the mortality dynamics of Scots pines, but how mistletoes promote pine decline remains unclear. To verify whether pine mistletoe infection weakens the host via crown degradation, as observed for dwarf mistletoes, we studied the negative effects of pine mistletoe infestation on the photosynthetic tissues and branch growth of pairs of infested and non-infested branches. Pine mistletoe infection leads to crown degradation in its host by reducing the length, the radial increment, the ramification, the needle length and the number of needle years of the infested branches. This massive loss in photosynthetic tissue results in a reduction in primary production and a subsequent decrease in carbohydrate availability. The significant reduction in needle length due to mistletoe infection is an indication for a lower water and nutrient availability in infested branches. Thus, mistletoe infection might lead to a decrease in the availability of water and carbohydrates, the two most important growth factors, which are already shortened due to the chronic drought situation in the area. Therefore, pine mistletoe increases the risk of drought-induced mortality of its host when growing in a xeric environment.}, language = {en} } @article{RiglingBiglerEilmannetal.2012, author = {Rigling, Andreas and Bigler, Christof and Eilmann, Britta and Feldmeyer-Christe, Elisabeth and Gimmi, Urs and Ginzler, Christian and Graf, Ulrich and Mayer, Phillip and Vacchiano, Giorgio and Weber, Pascal and Wohlgemuth, Thomas and zweifel, Roman and Dobbertin, Matthias}, title = {Driving factors of a vegetation shift from Scots pine to pubescent oak in dry Alpine forests}, series = {Global Change Biology}, volume = {19}, journal = {Global Change Biology}, number = {1}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1354-1013 (Print)}, doi = {10.1111/gcb.12038}, pages = {229 -- 240}, year = {2012}, abstract = {An increasing number of studies have reported on forest declines and vegetation shifts triggered by drought. In the Swiss Rhone valley (Valais), one of the driest inner-Alpine regions, the species composition in low elevation forests is changing: The sub-boreal Scots pine (Pinus sylvestris L.) dominating the dry forests is showing high mortality rates. Concurrently the sub-Mediterranean pubescent oak (Quercus pubescens Willd.) has locally increased in abundance. However, it remains unclear whether this local change in species composition is part of a larger-scale vegetation shift. To study variability in mortality and regeneration in these dry forests we analysed data from the Swiss national forest inventory (NFI) on a regular grid between 1983 and 2003, and combined it with annual mortality data from a monitoring site. Pine mortality was found to be highest at low elevation (below 1000 m a.s.l.). Annual variation in pine mortality was correlated with a drought index computed for the summer months prior to observed tree death. A generalized linear mixed-effects model indicated for the NFI data increased pine mortality on dryer sites with high stand competition, particularly for small-diameter trees. Pine regeneration was low in comparison to its occurrence in the overstorey, whereas oak regeneration was comparably abundant. Although both species regenerated well at dry sites, pine regeneration was favoured at cooler sites at higher altitude and oak regeneration was more frequent at warmer sites, indicating a higher adaptation potential of oaks under future warming. Our results thus suggest that an extended shift in species composition is actually occurring in the pine forests in the Valais. The main driving factors are found to be climatic variability, particularly drought, and variability in stand structure and topography. Thus, pine forests at low elevations are developing into oak forests with unknown consequences for these ecosystems and their goods and services.}, language = {en} } @article{LevesqueSiegwolfEilmannetal.2014, author = {L{\´e}vesque, Mathieu and Siegwolf, Rolf and Eilmann, Britta and Saurer, Matthias and Rigling, Andreas}, title = {Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions}, series = {New Phytologist}, volume = {203}, journal = {New Phytologist}, number = {1}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1469-8137 (Online)}, doi = {10.1111/nph.12772}, pages = {94 -- 109}, year = {2014}, language = {en} } @article{LevesqueSaurerSiegwolfetal.2013, author = {L{\´e}vesque, Mathieu and Saurer, Matthias and Siegwolf, Rolf and Eilmann, Britta and Brang, Peter and Bugmann, Harald and Rigling, Andreas}, title = {Drought response of five conifer species under contrasting water availability suggests high vulnerability of Norway spruce and European larch}, series = {Global Change Biology}, volume = {19}, journal = {Global Change Biology}, number = {10}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1365-2486 (Online)}, doi = {10.1111/gcb.12268}, pages = {3184 -- 3199}, year = {2013}, language = {en} } @article{FeichtingerEilmannBuchmannetal.2014, author = {Feichtinger, Linda M. and Eilmann, Britta and Buchmann, Nina and Rigling, Andreas}, title = {Growth adjustments of conifers to drought and to century-long irrigation}, series = {Forest Ecology and Management}, volume = {2014}, journal = {Forest Ecology and Management}, number = {334}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-7042 (Online)}, doi = {10.1016/j.foreco.2014.08.008}, pages = {96 -- 105}, year = {2014}, abstract = {Our knowledge on tree responses to drought is mainly based on short-term manipulation experiments which do not capture any possible long-term adjustments in this response. Therefore, historical water channels in inner-Alpine dry valleys were used as century-long irrigation experiments to investigate adjustments in tree growth to contrasting water supply. This involved quantifying the tree-ring growth of irrigated and non-irrigated (control) Scots pine (Pinus sylvestris L.) in Valais (Switzerland), as well as European larch (Larix decidua Mill.) and black pine (Pinus nigra Arnold) in Vinschgau (Italy). Furthermore, the adjustments in radial growth of Scots pine and European larch to an abrupt stop in irrigation were analyzed. Irrigation promoted the radial growth of all tree species investigated compared to the control: (1) directly through increased soil water availability, and (2) indirectly through increased soil nutrients and humus contents in the irrigated plots. Irrigation led to a full elimination of growth responses to climate for European larch and black pine, but not for Scots pine, which might become more sensitive to drought with increasing tree size in Valais. For the control trees, the response of the latewood increment to water availability in July/August has decreased in recent decades for all species, but increased in May for Scots pine only. The sudden irrigation stop caused a drop in radial growth to a lower level for Scots pine or similar level for larch compared to the control for up to ten years. However, both tree species were then able to adjust to the new conditions and subsequently grew with similar (Scots pine) or even higher growth rates (larch) than the control. To estimate the impact of climate change on future forest development, the duration of manipulation experiments should be on longer time scales in order to capture adjustment processes and feedback mechanisms of forest ecosystems.}, language = {en} } @article{FeichtingerEilmannBuchmannetal.2015, author = {Feichtinger, Linda M. and Eilmann, Britta and Buchmann, Nina and Rigling, Andreas}, title = {Trait-specific responses of Scots pine to irrigation on a short vs long time scale}, series = {Tree Physiology}, volume = {35}, journal = {Tree Physiology}, number = {00}, publisher = {Heron}, address = {Victoria, BC}, issn = {1758-4469 (Online)}, doi = {10.1093/treephys/tpu114}, pages = {1 -- 12}, year = {2015}, language = {en} } @article{EilmannZweifelBuchmannetal.2011, author = {Eilmann, Britta and Zweifel, Roman and Buchmann, Nina and Graf Pannatier, Elisabeth and Rigling, Andreas}, title = {Drought alters timing, quantity, and quality of wood formation in Scots pine}, series = {Journal of Experimental Botany}, volume = {62}, journal = {Journal of Experimental Botany}, number = {8}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1460-2431 (Online)}, doi = {10.1093/jxb/erq443}, pages = {2763 -- 2771}, year = {2011}, language = {en} } @article{EilmannZweifelBuchmannetal.2009, author = {Eilmann, Britta and Zweifel, Roman and Buchmann, Nina and Fonti, Patrick and Rigling, Andreas}, title = {Drought-induced adaptation of the xylem in Scots pine and pubescent oak}, series = {Tree Physiology}, volume = {29}, journal = {Tree Physiology}, number = {8}, publisher = {Heron}, address = {Victoria, BC}, issn = {0829-318X (Print)}, doi = {10.1093/treephys/tpp035}, pages = {1011 -- 1020}, year = {2009}, language = {en} } @article{EilmannWeberRiglingetal.2006, author = {Eilmann, Britta and Weber, Pascale and Rigling, Andreas and Eckstein, Dieter}, title = {Growth reactions of Pinus sylvestris L. and Quercus pubescens Willd. to drought years at a xeric site in Valais, Switzerland}, series = {Dendrochronologia}, volume = {23}, journal = {Dendrochronologia}, number = {3}, issn = {1612-0051 (Online)}, doi = {doi:10.1016/j.dendro.2005.10.002}, pages = {121 -- 132}, year = {2006}, language = {en} } @article{EilmannRigling2012, author = {Eilmann, Britta and Rigling, Andreas}, title = {Tree-growth analyses to estimate tree species' drought tolerance}, series = {Tree Physiology}, volume = {32}, journal = {Tree Physiology}, number = {2}, editor = {Abrams, Marc}, publisher = {Oxford University Press}, address = {Oxford}, issn = {0829-318X (Print)}, doi = {10.1093/treephys/tps004}, pages = {178 -- 187}, year = {2012}, abstract = {Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very drought-tolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species.}, language = {en} }