Drought Severity and Trends in a Mediterranean Oak Forest

Hydrology, Journal Year: 2023, Volume and Issue: 10(8), P. 167 - 167

Published: Aug. 10, 2023

Drought is a significant natural hazard with widespread socioeconomic and environmental impacts. This study investigated the long-term drought characteristics in Mediterranean oak forest ecosystem using Standardized Precipitation Evapotranspiration Index (SPEI) at various time scales seasons. The analysis was based on series dataset obtained from meteorological station located University Forest of Taxiarchis Greece. encompassed substantial span 47 years continuous monitoring, 1974 to 2020. To accomplish goals current research, SPEI calculated for 3, 6, 12, 24-month periods, events were identified. Mann-Kendall (M-K) test used analyze trends severity evaluate significance. results showed that shorter (SPEI3 SPEI6) more efficient identifying short-term droughts, while longer (SPEI12 SPEI24) better less frequent but longer-lasting episodes. consistently revealed positive across all seasons scales, indicating an overall transition towards wetter conditions. Nearly data SPEI12 SPEI24 exhibited statistically upward (wetter conditions) 95% confidence level. However, intense detected during recent decade seasonal analysis. Additionally, as scale expanded, magnitude these increased. findings contributed understanding dynamics forests provided valuable information management climate change adaptation planning.

Language: Английский

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Increasing atmospheric dryness reduces boreal forest tree growth

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Oct. 30, 2023

Rising atmospheric vapour pressure deficit (VPD) associated with climate change affects boreal forest growth via stomatal closure and soil dryness. However, the relationship between VPD depends on climatic context. Here we assess Canadian responses to changes from 1951-2018 using a well-replicated tree-growth increment network approximately 5,000 species-site combinations. Of 3,559 successful models, observed concurrent summer in one-third of combinations, prior almost half those The previous year current was exclusively negative, while also tended reduce growth. Tree species, age, annual temperature, moisture primarily determined tree responses. Younger trees species like white spruce Douglas fir exhibited higher sensitivity, as did areas high temperature low moisture. Since 1951, increases Canada have paralleled decreases, particularly species. Accelerating dryness decades ahead will impair carbon storage societal-economic services.

Language: Английский

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Tree crown defoliation in forest monitoring: concepts, findings, and new perspectives for a physiological approach in the face of climate change

Forestry An International Journal of Forest Research, Journal Year: 2024, Volume and Issue: 97(2), P. 194 - 212

Published: Jan. 5, 2024

Abstract Recurrent climate-driven disturbances impact on the health of European forests that reacted with increased tree dieback and mortality over course last four decades. There is therefore large interest in predicting understanding fate survival under climate change. Forest conditions are monitored within pan-European ICP Forests programme (UN-ECE International Co-operative Programme Assessment Monitoring Air Pollution Effects Forests) since 1980s, crown defoliation being most widely used parameter. Defoliation not a cause-specific indicator vitality, there need to connect levels physiological functioning trees. The responses connected species-specific concern, among others, water relations, photosynthesis carbon metabolism, growth, mineral nutrients leaves. indicators measure variables forest monitoring programs must be easy apply field current state-of-the-art technologies, replicable, inexpensive, time efficient regulated by ad hoc protocols. ultimate purpose provide data feed process-based models predict threats due This study reviews problems perspectives realization systematic assessment proposes set suitable for future application programs.

Language: Английский

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Nutritional changes in trees during drought‐induced mortality: A comprehensive meta‐analysis and a field study

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(1)

Published: Jan. 1, 2024

Abstract Both macronutrients and micronutrients are essential for tree growth development through participating in various ecophysiological processes. However, the impact of nutritional status trees on their ability to withstand drought‐induced mortality remains inconclusive. We thus conducted a comprehensive meta‐analysis, compiling data 11 nutrients from 44 publications (493 independent observations). Additionally, field study was Pinus sylvestris L. with varying vitality loss “Visp” forest southern Switzerland. No consistent decline observed during mortality. The meta‐analysis revealed significantly lower leaf potassium (K), iron (Fe), copper (Cu) concentrations showed no causal relationships between levels trees. This discrepancy is mainly attributed intrinsic differences two types experimental designs ontogenetic stages target Nutrient reductions preceding were predominantly non‐field conditions, where seedlings saplings underdeveloped root systems. It limits nutrient uptake capacity these young drought. Furthermore, responses also influenced by many variables. Specifically, (a) more susceptible drought stress than other organs; (b) reduced prevalent evergreen species mortality; (c) all biomes, Mediterranean forests most vulnerable deficiencies; (d) soil affect direction extent responses. identified factors that influence relationship survival, proposed potential early‐warning indicators impending mortality, example, decreased K declining vitality. These findings contribute our understanding provide practical implications management strategies context global change.

Language: Английский

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Forest growth resistance and resilience to the 2018–2020 drought depend on tree diversity and mycorrhizal type

Journal of Ecology, Journal Year: 2024, Volume and Issue: 112(8), P. 1787 - 1803

Published: July 12, 2024

Abstract The frequency of consecutive drought years is predicted to increase due climate change. These droughts have strong negative impacts on forest ecosystems. Mixing tree species proposed the resistance and resilience communities. However, this promising diversity effect has not yet been investigated under extreme conditions in context complementary mycorrhizal associations their potential role improving water uptake. Here, we investigate whether promotes growth responses are modulated by associations. We used inventory data (2015–2021) from a young experiment Germany, manipulating richness (1, 2 4 species) type (communities containing arbuscular [AM] or ectomycorrhizal [EM] species, both). For all communities, calculated basal area increment periods before, during after concepts quantify drought. found declines 2018–2020 for most Contrary our hypothesis, did find that per se can buffer growth. while EM decreased with richness, they increased AM communities comprising both types. highlight among various mixtures only those mixed types outperformed respective monocultures Furthermore, drought, community tends segregate into ‘winner’ ‘loser’ terms diversity, indicating possible intensification competition. While cannot disentangle underlying mechanisms clarify mycorrhiza findings suggest within could help safeguard forests against increasing frequency. Synthesis . Drought depend association diverse holds promise restoration face

Language: Английский

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Exploring the connection between climatic conditions and genetic properties of Abies alba Mill., including warm and summer-dry Mediterranean environments

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 964, P. 178559 - 178559

Published: Jan. 23, 2025

Abies alba Mill. is a prominent European tree species predominantly inhabiting cool and humid montane environments. However, paleoecological evidence reveals that during the Eemian mid-Holocene, A. thrived in much warmer drier climates. This capacity nowadays reflected cryptic meso- sub-Mediterranean lowland populations. To link populations across diverse climates spanning from Mediterranean lowlands to Alpine timberline, we genotyped 421 specimens Italy Switzerland at 190 single-nucleotide polymorphisms (SNPs). Population genetic structure analyses indicate isolated Tuscany Ticino align genetically with higher elevation each region, suggesting their thrive warmer, conditions cannot be attributed plantations planting stock originating different or occurrence of single warm-adapted lineage showing disjunct distribution, unless migration between stands occurred. Genotype-environment associations reveal temperature seasonality, precipitation critical seasons, relative humidity are important for explaining species' variation. With genotype-environment genotype-phenotype associations, identified candidate adaptive genes potentially linked climatic drought response. While certain alleles may have spread Southern could explained by shared ancestry Tuscan populations, local adaptation occurred specific loci. These findings underscore importance considering hitherto overlooked better understand niche its potential forest conservation management under global warming.

Language: Английский

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Genetic Differentiation of Abies alba Outside Its Main Range Under Warm Meso‐ and Sub‐Mediterranean Conditions in Italy and Switzerland

Ecology and Evolution, Journal Year: 2025, Volume and Issue: 15(2)

Published: Feb. 1, 2025

Abies alba is an important European tree species currently mostly found at cool and humid sites in the montane zone. In past, it grew under markedly warmer drier climates during Eemian mid-Holocene, cryptic Mediterranean populations confirm species' capacity to grow warm, summer-dry conditions. However, unknown if warm-loving occurrences are related specific genetic properties (e.g., subspecies or ecotypes). Investigating genetics of crucial for a better understanding past future population dynamics A. alba. We genotyped 478 samples 174 single-nucleotide polymorphisms (SNP), covering broad latitudinal range from Southern Italy Switzerland while accounting local altitudinal gradients, combined these newly introduced genotypes with those other literature. Population structure analyses grouped meso- sub-Mediterranean into same cluster as mountain each region. The occurrence three clusters Northern line glacial refugia history. inferred evolutionary demographic history suggests northward expansion after glaciation, well trans-Adriatic gene flow between Balkan Italian populations. Collectively, genotypic data individuals across demonstrate that align large-scale its main range, suggesting able thrive environmental than hitherto anticipated. This finding implies unneeded postulate extinct ecotypes explain mid-Holocene silver fir forests, implications dynamics.

Language: Английский

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Retrospective analysis of wood anatomical traits and tree‐ring isotopes suggests site‐specific mechanisms triggering Araucaria araucana drought‐induced dieback

Global Change Biology, Journal Year: 2021, Volume and Issue: 27(24), P. 6394 - 6408

Published: Sept. 13, 2021

Abstract In 2010–2018, Northern Patagonia featured the longest severe drought of last millennium. This extreme dry spell triggered widespread growth decline and forest dieback. Nonetheless, roles played by two major mechanisms driving dieback, hydraulic failure carbon starvation, are still not clear understudied in this seasonally region. Here, for 1800–2017 period, we apply a retrospective analysis radial growth, wood anatomical traits (lumen area, cell‐wall thickness) δ 13 C 18 O stable isotopes to assess dieback causes iconic conifer Araucaria araucana . We selected three stands where declining (defoliated) nondeclining (not defoliated) trees coexisted along precipitation gradient from warm‐dry Coastal Range cool‐wet Andes. At all sites showed lower theoretical conductivity, suggesting long‐lasting process deterioration their water transport system compared nondeclining, coexisting trees. Wood evidenced that divergence between started at least seven decades before canopy drier stands, higher water‐use efficiency (WUE) throughout whole which attributed early stomatal closure, greater starvation risk consistent with thinner cell walls. wettest stand, found opposite pattern. reduction WUE coupled thicker walls suggested increased assimilation rates exposure drought‐induced failure. The values indicated different strategies gas exchange sites, likely consequence microsite conditions sources. Multiproxy, quantifications xylem tree‐ring provide robust tool identify forecast, or will show or, on contrary, withstand be more resilient future hotter droughts.

Language: Английский

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The role of nutritional impairment in carbon‐water balance of silver fir drought‐induced dieback

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(14), P. 4439 - 4458

Published: March 23, 2022

Rear-edge populations at the xeric distribution limit of tree species are particularly vulnerable to forest dieback triggered by drought. This is case silver fir (Abies alba) forests located in Southwestern Europe. While drought-induced patterns have been previously explored, information on role played nutritional impairment lacking despite its potential interactions with carbon-water balances. We performed a comparative analysis radial growth, intrinsic water-use efficiency (iWUE), oxygen isotopes (δ18 O) and nutrient concentrations leaves declining (DD) non-declining (ND) trees four Spanish Pyrenees. also evaluated relationships among predisposition, intraspecific trait variation (wood density leaf traits) rhizosphere soil physical-chemical properties. The onset growth decline DD occurred more than two decades ago, they subsequently showed low resilience against droughts. presented consistently lower foliar nutrients such as P, K, Cu Ni ND trees. strong effects status indices support key mineral nutrition functioning before, during after In contrast, variability wood morphological traits, well properties, weak drought performance. At elevation, warmer sites, stronger climate-growth δ18 O uncoupling between iWUE O, together positive correlations P K point deeper soil/bedrock water sources vertical decoupling uptake study provides novel insights into mechanisms driving highlights need incorporate studies.Las poblaciones del límite xérico de distribución las especies árboles son particularmente vulnerables al decaimiento forestal inducido por sequía. Este es el caso los bosques abeto situados en suroeste Europa. Si bien patrones provocado sequía se han explorado previamente, falta información sobre papel que desempeña deterioro nutricional pesar sus interacciones potenciales con balances agua y carbono árboles. En este estudio, hemos realizado un análisis comparativo crecimiento radial, la eficiencia intrínseca uso isótopos oxígeno (δ18O) concentraciones nutrientes hojas decaídos no cuatro abetares Pirineos españoles. También evaluamos relaciones entre predisposición decaimiento, variación rasgos intraespecíficos (densidad madera hojas) propiedades físico-químicas rizosfera. El inicio disminución ocurrió hace más dos décadas posteriormente mostraron una baja resiliencia frente sequías. Los presentaron foliares consistentemente bajas como ND. fuertes efectos estado índices respaldan clave nutrición funcionamiento antes, durante después contraste, variabilidad densidad morfológicos hojas, así suelo, relación débil respuesta sitios cálidos elevación, clima-crecimiento bajo desacoplamiento junto correlaciones positivas apuntan fuentes profundas suelo/lecho rocoso absorción DD. estudio proporciona novedosa mecanismos impulsan destaca necesidad incorporar estudios muerte regresiva bosque.

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Species-specific indication of 13 tree species growth on climate warming in temperate forest community of northeast China

Ecological Indicators, Journal Year: 2021, Volume and Issue: 133, P. 108389 - 108389

Published: Nov. 20, 2021

Temperate forests in northeast Asia are crucial to maintaining biodiversity conservation and ecological security. Under the background of global warming drought, it is great significance study special indicator effect tree growth on climate change. Dendrochronological analysis different species same community under change can provide valuable information for adaptive potential species-specific indications. Here, we compared radial patterns 13 co-occurring a temperate forest China. Pearson correlation moving interval were used reveal key factors affecting temporal stability growth-climate relationships, respectively. Results showed that temperature moisture played role The Pinus sylvestris var. mongolica, Picea koraiensis, Ulmus davidiana increased significantly after rapid (around 1980s), while Acer mono, Betula platyphylla decreased slightly. almost all (except P. A. B. platyphylla) had positive indication temperature, especially Juglans mandshurica, Fraxinus U. davidiana. precipitation early growing season (May June) relative humidity positively correlated with most species. Coniferous diffuse-porous more resistant recovery extreme droughts than semi-ring-porous ring-porous davidiana). species, conifers, low resistance high temperature. differences relationships among may be related wood properties habits. If continues warm, coniferous trees will suffer serious impact, so they need protection most. Our results highlight differentiated strategies needed management restoration due indications warming.

Language: Английский

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