A century of tree line changes in sub-Arctic Sweden shows local and regional variability and only a minor influence of 20th century climate warming
Summary (1 min read)
A century of tree line changes in sub-Arctic Sweden shows local and regional
- Twentieth century tree line changes in Swedish sub-Arctic Abstract 1 Models project that climate warming will cause the treeline to move to higher 2 elevations in alpine areas and more northerly latitudes in Arctic environments, also known as Running head.
- The lack of 446 recent tree (>2 m) establishment and the browsing scars documented in the tree rings 447 indicated that, in addition to moth herbivory, reindeer browsing is still a controlling 448 factor at these sites (Fig. 5, Table 4).
Tables
- Previous field studies on observed treeline shifts and their presumed causes in the Torneträsk area of sub-Arctic Sweden.
- Browsing damage was classified visually and for five sites also by dendrochronological analysis (the values listed in brackets).
- So as not to bias the results, Mount Nuolja (site S3), for which the two treeline sites were not randomly selected, was not included in the calculation of the mean elevational shift of the treeline in the Torneträsk area.
- Pearson correlation coefficients and R2-values (the proportion of explained variance in documented treeline shifts) obtained by forward selection of the different variables are listed at the bottom of the table.
Figure legends
- The Torneträsk study area in sub-Arctic Sweden.
- The locations of the historical transects and photo points that have been revisited to study changes in the tree line ecotone are indicated.
- The statistically-determined 30%-tree cover isoline is plotted in yellow.
- Upper photo on the left: E. Persson, bottom left: B. Mesch; upper and bottom right: R. Van Bogaert.
- Fig. 8. Tree (>2 m) establishment at the Torneträsk tree line versus summer (June- August) temperature and reindeer population numbers for the period 1800-2000.
Figures
- Historical transects and photo points that have been revisited to study changes in the tree line ecotone are indicated.
- The statistically-determined 30% tree-cover isoline is plotted in yellow.
- Upper photo: E. Persson, lower photo: S. Johnsson.
- Upper photo on the left: E. Persson, bottom left: B. Mesch; upper and bottom right: R. Van Bogaert. relation to disturbance (b) and summer temperature (c) for the period 1964-2006.
- August) temperature and reindeer population numbers for the period 1800-2000.
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Citations
47 citations
Cites background from "A century of tree line changes in s..."
...Defoliation caused by the outbreaks of herbivorous moths influences tree-ring growth (Hoogesteger & Karlsson 1992; Karlsson et al. 2004; Van Bogaert et al. 2009)....
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...The dominance of herbivory over climate in determining birch growth is consistent with the importance of herbivory in determining tree line shifts (Speed et al. 2010; Van Bogaert et al. 2011)....
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47 citations
43 citations
Cites background from "A century of tree line changes in s..."
...2009), only a few published studies have included quantitative data about treeline shifts (Devi et al. 2008, Kullman & Öberg 2009, Diaz-Varela et al. 2010, Van Bogaert et al. 2011)....
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...Glob Change Biol 21: 2005−2021 De Frenne P, Rodríguez-Sánchez F, De Schrijver A, Coomes DA, Hermy M, Vangansbeke P, Verheyen K (2015) Light accelerates plant responses to warming....
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...Since 680 AD: intensive HADCM3_A2, Rocky sites; extreme Velchev (1997), fires, deforestation and grazing; CGGM2, hydrothermal conditions; Grunewald & since 1962: traditional mng ΔT2050 = 1.7°C, competition of shrubs and tree Scheithauer (2011), has changed; last decades tourism ΔT2080 = 2....
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...Since 680 AD: intensive HADCM3_A2, Rocky sites; extreme Velchev (1997), fires, deforestation and grazing; CGGM2, hydrothermal conditions; Grunewald & since 1962: traditional mng ΔT2050 = 1....
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...J For Sci 56: 505−517 Van Bogaert R, Haneca K, Hoogesteger J, Jonasson C, de Dapper M, Callaghan TV (2011) A century of tree line changes in sub-Arctic Sweden shows local and regional variability and only a minor influence of 20th century climate warming....
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42 citations
Cites background from "A century of tree line changes in s..."
...). responses across elevation as opposed to latitude (Walther et al., 2005; Beckage et al., 2008; Holzinger et al., 2008; Kelly and Goulden, 2008; Lenoir et al., 2008; Harsch et al., 2009; Lenoir et al., 2009; Crimmins et al., 2011; Feeley et al., 2011; Van Bogaert et al., 2011)....
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...Emerging work by Van Bogaert et al. (2011) suggests a similar finding that disturbance may be a stronger controlling factor on tree ranges than recent climatic trends....
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40 citations
Cites background from "A century of tree line changes in s..."
...Although these rates are not supported by empirical data (Lloyd 2005; Van Bogaert et al. 2011; Hofgaard et al., forthcoming), tundra habitats and biodiversity are being affected by local, regional and global pressures including tree and shrub encroachment....
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References
1,775 citations
1,003 citations
"A century of tree line changes in s..." refers background in this paper
...In contrast to Harsch et al. (2009) who concluded that the role of disturbance during recent climate warming is restricted to determining when tree line advance will occur, this study shows that disturbance and its after-effects may equally well determine ı́f tree line advance will occur at all....
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...As the location of elevational and polar tree lines is mainly caused by heat deficiency, in the Northern Hemisphere climate warming is expected to cause tree lines to advance to higher elevations and more northerly latitudes (Harsch et al., 2009)....
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...…widely held expectations of vegetation responses to warming, i.e. that Arctic tree lines will move northwards and elevational tree lines upslope (Harsch et al., 2009), this study documented highly varying tree line dynamics for the Torneträsk area in sub-Arctic Sweden during a period of…...
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...A global study by Harsch et al. (2009) showed that only 52% of all 166 global tree line sites had advanced over the past 100 years despite documented amplified climate warming at high-elevation areas and northern latitudes (ACIA, 2005)....
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518 citations
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"A century of tree line changes in s..." refers result in this paper
...In contrast to other studies (Danby & Hik, 2007; Kullman & Öberg, 2009), slope aspect and inclination were not correlated with elevational shifts of the tree line ecotone....
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