Drought sensitivity of Norway spruce is higher than that of silver fir along an altitudinal gradient in southwestern Germany

Abstract

For Central Europe, climate projections foresee an increase in temperature combined with decreasing summer precipitation, resulting in drier conditions during the growing season. This might negatively affect forest growth, especially at sites that are already water-limited, i.e., at low elevation. At higher altitudes trees might profit from increasing temperatures. We analyzed variations in radial growth of silver fir (Abies alba Mill.) and Norway spruce (Picea abies (L.) Karst.) along an altitudinal gradient from 400 until 1140 m a.s.l. in the Black Forest, to assess climate responses with increasing elevation. Climate-growth relationships were analyzed retrospectively using tree-ring and climate data. In total, we sampled stem discs of 135 trees to build 27 species-and site-specific chronologies (n f ir = 13, n spruce = 14). Our results indicate distinct differences in climate-growth relations between fir and spruce along the gradient. Growth of high-altitude fir was positively related to temperature from January till March. Growth of low-altitude fir and spruce at all elevations was positively related to precipitation and negatively to temperature during the growing season, particularly in July. A self-calibrating Palmer drought severity index (sc-PDSI) underlined summer drought sensitivity of these trees. Overall, we found that climatic control of tree growth changes over altitude for fir. For spruce, a remarkable synchrony in growth variation and climate response was shown, which indicates that this species is drought sensitive at all studied elevations. In a future warmer climate, the growth of low-altitude fir and spruce along the entire studied gradient may be negatively affected in the Black Forest, if an increased evaporative demand cannot be compensated by increased water supply.

Contrasting resistance and resilience to extreme drought and late spring frost in five major European tree species

“…Moreover, both hydraulic and carbon constraints (Herms & Mattson, ; McDowell et al, ) can lead to general metabolic limitations as indicated by impaired carbon transport from sources to sinks (Ruehr et al, ) or reduced allocation to defense compounds (McDowell et al, ) and the consequences thereof might strongly determine the recovery trajectories. Our findings are in agreement with recent dendroecological studies showing a higher vulnerability of spruce and larch to drought than fir (Lévesque et al, ; van der Maaten‐Theunissen, Kahle, & Maaten, ; Vitali, Buntgen, & Bauhus, ), which is also in line with studies showing a high sensitivity of spruce to elevated VPD (Sanginés de Cárcer et al, ) and the inability of its root system to access deep water layers during summer drought (Brinkmann, Eugster, Buchmann, & Kahmen, ). Our study also confirms that sessile and pedunculate oaks are able to cope with severe hot drought, as previously suggested in a study focusing on its water status and photosynthesis during the extremely hot drought in 2003 (Leuzinger, Zotz, Asshoff, & Körner, ).…”

A model‐data comparison of Holocene timberline changes in the Swiss Alps reveals past and future drivers of mountain forest dynamics

“…Our simulation indicates that A. alba can grow under lower moisture conditions than Picea abies in the study area, which is in agreement with ecological studies (e.g. Zingg & Bürgi, ; Ellenberg & Leuschner, ; van der Maaten‐Theunissen et al ., ). Indeed, the expansion of silver fir at ca.…”

Soil nutrients influence growth response of temperate tree species to drought

“…Scots pine and silver fir were insensitive to temperature. Both species are known to be less temperature and drought sensitive than spruce at low elevation sites (van der Maaten‐Theunissen, Kahle & van der Maaten ; Lévesque et al . ; Zang et al .…”