Inter- and intra-specific variation in drought sensitivity in Abies spec. and its relation to wood density and growth traits

Abstract

Understanding drought sensitivity of tree species and its intra-specific variation is required to estimate the effects of climate change on forest productivity, carbon sequestration and tree mortality as well as to develop adaptive forest management measures. Here, we studied the variation of drought reaction of six European Abies species and ten provenances of Abies alba planted in the drought prone eastern Austria. Tree-ring and X-ray densitometry data were used to generate early- and latewood measures for ring width and wood density. Moreover, the drought reaction of species and provenances within six distinct drought events between 1970 and 2011, as identified by the standardized precipitation index, was determined by four drought response measures. The mean reaction of species and provenances to drought events was strongly affected by the seasonal occurrence of the drought: a short, strong drought at the beginning of the growing season resulted in growth reductions up to 50%, while droughts at the end of the growing season did not affect annual increment. Wood properties and drought response measures showed significant variation among Abies species as well as among A. alba provenances. Whereas A. alba provenances explained significant parts in the variation of ring width measures, the Abies species explained significant parts in the variation of wood density parameters. A consistent pattern in drought response across the six drought events was observed only at the inter-specific level, where A. nordmanniana showed the highest resistance and A. cephalonica showed the best recovery after drought. In contrast, differences in drought reaction among provenances were only found for the milder drought events in 1986, 1990, 1993 and 2000 and the ranking of provenances varied at each drought event. This indicates that genetic variation in drought response within A. alba is more limited than among Abies species. Low correlations between wood density parameters and drought response measures suggest that wood density is a poor predictor of drought sensitivity in Abies spec.

Assessing forest vulnerability to climate warming using a process‐based model of tree growth: bad prospects for rear‐edges

“…This could be the case for the southernmost studied tree populations located at the lowest elevations, which were most dependent on spring and early summer climate conditions. Tree species show adaptive features to increasing drought stress by adjusting their hydraulic system (e.g., leaf area to sapwood area ratio) and phenology to local climate, particularly those most widespread as Scots pine (Martínez‐Vilalta et al ., ) and silver fir (George et al ., ). Our modeling approach could help to highlight locally adapted populations with traits providing drought tolerance and to derive predictions on future dieback events by mapping growth vulnerability.…”

Forest adaptation to climate change—is non-management an option?

“…Provenance trials have confirmed that spruce grows on a wide range of site conditions. Provenances that are tolerant towards warm and dry In addition, Silver fir is seen as option at sites that are unsuitable for Norway spruce (Kapeller et al 2012;George et al 2015).…”

The Effect of Insect Defoliations and Seed Production on the Dynamics of Radial Growth Synchrony among Scots Pine Pinus sylvestris L. Provenances

“…Adverse climatic conditions, mainly related to severe soil water deficit, may modify growth patterns and thus enhance the level of synchronicity among trees and provenances [14,15]. However, even if among-provenance differences in drought reaction are noticeable, these relationships may be temporally unstable, suggesting the phenotypic instability of provenances and/or the modifying effect of non-climatic factors [16,17]. Temporal instability in climate-growth relationships has been mainly observed in natural populations of forest trees [18][19][20][21], indicating at least two causal factors-current and past climate instability-as well as age-related trends in radial growth dynamics [22][23][24].…”