Dendroclimatological Investigations of Sea Buckthorn (Hippophae rhamnoides) and Reconstruction of the Equilibrium Line Altitude of the July First Glacier in the Western Qilian Mountains, Northwestern China

Abstract

Radial growth characteristics of a high-elevation shrub species, sea buckthorn (Hippophae rhamnoides), were investigated at four sites in a river valley at altitudes ranging from 3,333 to 3,820 m a.s.l. close to the terminus of the July First Glacier in the western Qilian Mountains of northwestern China. Radial growth of the sea buckthorn was significantly and positively correlated with the mean monthly temperature in June of the current growing season. Based on the fact that fluctuations in the shrub's radial growth and the glacier's equilibrium-line altitude (ELA) are affected by climatic variables, a tree-ring width chronology of the four sites was used to reconstruct the ELA from 1950 to 2003. The resulting ELA model explained more than 55.3% of the variance in the ELA of the July First Glacier series. On a decadal time scale, the cumulative-departure curve of the reconstructed ELA series showed an increasing trend from the 1950s to the mid-1960s, followed by a descending trend from the mid-1960s to the mid-1970s. The ELA appears to have remained stable from the mid-1970s to the mid-1990s, but has displayed dramatic variations during the past decade.

How do climate and topography influence the greening of the forest‐tundra ecotone in northern Québec? A dendrochronological analysis of Betula glandulosa

“…Indeed, dendrochronological studies reveal positive relationships between shrub growth and temperature (Xiao et al . ; Bär et al . ; Liang & Eckstein ; Forbes, Macias Fauria & Zetterberg ; Hallinger, Manthey & Wilmking ; Blok et al .…”

“…Shrub expansion is commonly attributed to the recent increase in temperature at high latitudes (Myers-Smith et al 2011) through an overall increase in shrub growth. Indeed, dendrochronological studies reveal positive relationships between shrub growth and temperature (Xiao et al 2007;B€ ar et al 2008;Liang & Eckstein 2009;Forbes, Macias Fauria & Zetterberg 2010;Hallinger, Manthey & Wilmking 2010;Blok et al 2011;Hantemirov, Shiyatov & Gorlanova 2011;Boudreau & Villeneuve-Simard 2012), and, to a lesser extent, with winter (Liang & Eckstein 2009;Hallinger, Manthey & Wilmking 2010;Schmidt et al 2010) and summer precipitation. These results are corroborated by other studies that have shown an increase in deciduous shrub species abundance when subjected to experimental warming (Hobbie & Chapin 1998;Jonsdottir et al 2005;Walker et al 2006;Elmendorf et al 2012), especially when combined with nutrient addition (Chapin et al 1995;Chapin & Shaver 1996;Bret-Harte et al 2001;Zamin & Grogan 2012;Paradis, Mercier & Boudreau 2014).…”

Up to 400‐year‐old Rhododendron shrubs on the southeastern Tibetan Plateau: prospects for shrub‐based dendrochronology

“…In spite of an early dendrochronological attempt with shrub species in the 1950s (Ferguson 1959), actual progress has only been achieved in the last two decades (e.g. Rayback & Henry 2005;Schweingruber & Poschlod 2005;Au & Tardif 2007;Xiao et al 2007;Camarero et al 2013). Most dendrochronological studies on shrubs have encountered difficulties in cross-dating the extremely narrow, sometimes wavy or wedging growth rings (e.g.…”

Analyses of geographical observations in the Heihe River Basin: Perspectives from complexity theory

“…Global warming also has exacerbated this deterioration. The glacier area in the HRB has been characterized by a trend of negative mass balance and an increase in runoff (Xiao et al, 2007) since the 1990s. In fact, it has decreased by 29.6% over the past 50 years (Wang et al, 2011).…”