Auswirkungen des Trockensommers 2018 auf Flächen der Interkantonalen Walddauerbeobachtung

Braun, Sabine; Witte, Lucienne C. de; Hopf, Sven E.

doi:10.3188/szf.2020.0270

Cited by 13 publications

(12 citation statements)

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“…Standard errors and confidence intervals of the SEA for all analyses at a 60% threshold can be found in Supplementary Tables 6, 10. Beech is considered a species with a basic 2 years mast cycle (Matthews, 1955;Braun et al, 2020a;Nussbaumer et al, 2020). In our beech data, such a pattern was partly present but not dominant (Supplementary Figure 3).…”

Section: Statistical Analysesmentioning

confidence: 85%

Contrasting Resource Dynamics in Mast Years for European Beech and Oak—A Continental Scale Analysis

Nussbaumer

Geßler²,

Benham³

et al. 2021

Front. For. Glob. Change

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Resource allocation to different plant tissues is likely to be affected by high investment into fruit production during mast years. However, there is a large knowledge gap concerning species-specific differences in resource dynamics. We investigated the influence of mast years on stem growth, leaf production, and leaf carbon (C), nitrogen (N), and phosphorus (P) concentrations and contents in Fagus sylvatica, Quercus petraea, and Q. robur at continental and climate region scales using long-term data from the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) and similar datasets. We discussed the results in the light of opposing resource dynamics hypotheses: (i) resource accumulation before mast years and exhaustion after mast years (resource storage hypothesis), (ii) shifting resources from vegetative to generative compartments (resource switching hypothesis), and (iii) investing resources concurrently in both vegetative and generative compartments (resource matching hypothesis). Linear mixed-effects modelling (LMM) showed that both stem growth and leaf production were negatively influenced by weather conditions which simultaneously lead to high fruit production. Thus, the impact of generative on vegetative growth is intermixed with effects of environmental factors. Superposed epoch analyses and LMM showed that for mast behaviour in F. sylvatica, there are indicators supporting the resource storage and the resource switching hypotheses. Before mast years, resources were accumulated, while during mast years resources switched from vegetative to generative tissues with reduced stem and leaf growth. For the Quercus species, stem growth was reduced after mast years, which supports the resource storage hypothesis. LMM showed that leaf C concentrations did not change with increasing fruit production in neither species. Leaf N and P concentrations increased in F. sylvatica, but not in Quercus species. Leaf N and P contents decreased with increasing fruit production in all species, as did leaf C content in F. sylvatica. Overall, our findings suggest different resource dynamics strategies in F. sylvatica and Quercus species, which might lead to differences in their adaptive capacity to a changing climate.

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Section: Statistical Analysesmentioning

confidence: 85%

Contrasting Resource Dynamics in Mast Years for European Beech and Oak—A Continental Scale Analysis

Nussbaumer

Geßler²,

Benham³

et al. 2021

Front. For. Glob. Change

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“…Especially F . sylvatica is currently widely affected by drought‐induced defoliation and tree mortality following the extreme 2018/2019 drought (Braun et al ., 2020; Schuldt et al ., 2020). According to dendroecological analyses, this species is more drought‐sensitive than A .…”

Section: Discussionmentioning

confidence: 99%

“…These two species even turned out to be a match-in terms of hydraulic safety-for another major timber species of the region, namely sessile oak (Quercus petraea), which is known to be more drought-resistant than European beech (P 50 : −5.0 MPa to −4.6 MPa, HSM: 1.8 MPa to 2.3 MPa; based on P 50 and P min data from Dietrich et al, 2018;Lobo et al, 2018). Especially F. sylvatica is currently widely affected by drought-induced defoliation and tree mortality following the extreme 2018/2019 drought (Braun et al, 2020;Schuldt et al, 2020). According to dendroecological analyses, this species is more drought-sensitive than A. platanoides even in the core area of its distribution range (Zimmermann et al, 2015;Leuschner, 2020).…”

Section: Hydraulic Safety In Comparison To Major Timbersmentioning

confidence: 99%

“…are approaching their drought limit (van der Maaten‐Theunissen et al ., 2013; Lévesque et al ., 2014; Leuschner, 2020). Since 1980, this region has experienced a continuous increase in temperature and concomitantly in atmospheric vapour pressure deficit (Schuldt et al ., 2020), which culminated in a massive tree dieback of these two primary timber species in many central European forests during the exceptional 2018/2019 drought (Braun et al ., 2020; Schuldt et al ., 2020; Senf et al ., 2020). At least in the drier regions of central Europe, there is an urgent need to identify native timber species suited for production forests that better withstand drought and heat.…”

Section: Introductionmentioning

confidence: 99%

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Hydraulic variability of three temperate broadleaf tree species along a water availability gradient in central Europe

et al. 2021

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Plant hydraulic traits are key for understanding and predicting tree drought responses. Information about the degree of the traits' intra-specific variability may guide the selection of drought-resistant genotypes and is crucial for trait-based modelling approaches.For the three temperate minor broadleaf tree species Acer platanoides, Carpinus betulus and Tilia cordata, we measured xylem embolism resistance (P 50 ), leaf turgor loss point (P TLP ), specific hydraulic conductivity (K S ), Huber values (HVs), and hydraulic safety margins in adult trees across a precipitation gradient. We further quantified trait variability on different organizational levels (inter-specific to within-canopy variation), and analysed its relationship to climatic and soil water availability.Although we observed a certain intra-specific trait variability (ITV) in safety-related traits (P 50 , P TLP ) with higher within-tree and between-tree than between populations variability, the magnitude was small compared to inter-specific differences, which explained 78.4% and 58.3% of the variance in P 50 and P TLP , respectively. In contrast, efficiency-related traits (K S , HV) showed a high ITV both within populations and within the crowns of single trees. Surprisingly, the observed ITV of all traits was neither driven by climatic nor soil water availability.In conclusion, the high degree of conservatism in safety-related traits highlights their potential for trait-based modelling approaches.

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“…Drought-induced tree mortality has been documented worldwide (Allen et al 2010 , 2015 ; Hartmann et al 2018 ), including European temperate forests (Braun et al 2020 ; Schuldt et al 2020 ). The capability of different tree species to survive extreme drought intensities varies, but reliable trait-based predictions of future climate warming-related vitality reductions and forest community changes do rarely exist due to insufficient knowledge of plant trait variability (cf.…”

Section: Introductionmentioning

confidence: 99%

Soil water availability and branch age explain variability in xylem safety of European beech in Central Europe

et al. 2022

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Xylem embolism resistance has been identified as a key trait with a causal relation to drought-induced tree mortality, but not much is known about its intra-specific trait variability (ITV) in dependence on environmental variation. We measured xylem safety and efficiency in 300 European beech (Fagus sylvatica L.) trees across 30 sites in Central Europe, covering a precipitation reduction from 886 to 522 mm year−1. A broad range of variables that might affect embolism resistance in mature trees, including climatic and soil water availability, competition, and branch age, were examined. The average P50 value varied by up to 1 MPa between sites. Neither climatic aridity nor structural variables had a significant influence on P50. However, P50 was less negative for trees with a higher soil water storage capacity, and positively related to branch age, while specific conductivity (Ks) was not significantly associated with either of these variables. The greatest part of the ITV for xylem safety and efficiency was attributed to random variability within populations. We conclude that the influence of site water availability on P50 and Ks is low in European beech, and that the high degree of within-population variability for P50, partly due to variation in branch age, hampers the identification of a clear environmental signal.

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Auswirkungen des Trockensommers 2018 auf Flächen der Interkantonalen Walddauerbeobachtung

Cited by 13 publications

References 0 publications

Contrasting Resource Dynamics in Mast Years for European Beech and Oak—A Continental Scale Analysis

Contrasting Resource Dynamics in Mast Years for European Beech and Oak—A Continental Scale Analysis

Hydraulic variability of three temperate broadleaf tree species along a water availability gradient in central Europe

Soil water availability and branch age explain variability in xylem safety of European beech in Central Europe

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