This study investigates the wood anatomical diversity and functional trait coordination of eight co-occurring timber species in a North Ecuadorian seasonal tropical rainforest, an ecosystem heavily influenced by the Intertropical Convergence Zone (ITCZ). We integrated traditional qualitative and quantitative descriptions under International Association of Wood Anatomists (IAWA) standards with the advanced multi-table Structuring de Tableaux à Trois Indices de la Statistique (STATIS DUAL) framework to resolve three-dimensional structural relationships without external environmental datasets. Qualitative characterization revealed a gradient of cambial responses, capturing highly distinct growth ring boundaries in Platymiscium pinnatum and Cedrela odorata, and unexpected intermediate boundaries in Brosimum utile and Dialyanthera gracilipes. Quantitatively, the Inter-structure analysis of STATIS DUAL confirmed a robust, biophysically constrained core blueprint (74.3 % shared variance), where the Hilbert-Smith vectorial correlation coefficient ( RV ) exposed the highest structural synchronization ( RV = 0.92) among Zanthoxylum riedelianum, B. utile, and D. gracilipes, while Castilla elastica decoupled from the common matrix. The Consensus (compromise) configuration isolated a clear orthogonal segregation between primary wood systems, proving that vertical transport pathways operate independently from horizontal storage matrices and mechanical elongation. Furthermore, the Intra-structure analysis successfully mapped species-specific architectural trajectories across cutting planes, isolating an exceptionally plastic cellular arrangement and unique structural variation in P. pinnatum. By resolving these multi-plane anatomical baselines and species-specific trajectories, this research successfully models how community-level blueprints and individualistic structural strategies co-occur to secure ecological resilience and architectural adaptation against seasonal environmental stress within highly vulnerable tropical ecosystems.

Although recognized as Asia’s “Water Tower”, our understanding of past natural and recent anthropogenic enforced climate change is limited for much of the Himalayas. The main contributing factors for that are sparse and short meteorological observations, seasonally restricted and often imprecise proxy archives, and spatially heterogeneous and temporally unstable climate dynamics. Here we present a network of five maximum latewood density (MXD) chronologies from 135 living fir (Abies spectabilis) trees from sites near the upper treeline between 3220 and 3750 m a.s.l. in Nepal. Individual series were processed to preserve interannual, decadal, and centennial-scale variability. The resulting composite chronology was calibrated against April–September (AMJJAS) temperatures over the period 1951–2022 CE (rs = 0.64; p < 0.001), enabling the first MXD network-based temperature reconstruction for the Central Himalayas. Despite the relatively short reconstruction coverage (1775–2022 CE), it by far surpasses any regional instrumental record and explains more than 40

Germany has one of the most extensive railway networks in Europe. Due to the effects of climate change and the increasing frequency of extreme weather events, there is a growing risk to railway infrastructure posed by poor vitality of trees along rail tracks. Due to the forest edge effect, these trackside trees are exposed to greater variation in temperature and humidity, and are more strongly affected by weather extremes than their equivalents within a forest stand.The project RailVitaliTree (Tree vitality monitoring and modelling of drought-related risks along railroads with remote sensing and dendroecology) has a multidisciplinary approach, using remote sensing, dendroecological, and hydroclimatic analyses, to study tree vitality and microclimatic conditions along the German railway network. For this, increment cores of Quercus robur and Pinus sylvestris were extracted at four sites per species, where each site consists of a subsite along the railway and a corresponding reference in the forest.Our results show that trees along the railway had higher radial growth than reference trees in the forest. In fact, although mean series produced by pooling all trackside and all reference trees display that the growth trend of trackside and reference trees is highly synchronous (Q. robur GLK = 0.87; r = 0.83 and P. sylvestris GLK = 0.82; r = 0.60), the mean ring width and basal area increment of trackside trees were higher than that of the reference trees. So why do these trees seemingly grow better along railway tracks?Despite more radial growth, trackside trees of either species did not show a notably stronger response to climate parameters than the reference. However, there was a greater relative decrease in ring width and basal area increment of trackside trees in both species during known drought years. In order to investigate this difference in sensitivity and growth of trackside trees during drought events we use a high-resolution, species-specific drought-stress index developed by the German Meteorological Service, identifying when plant-available soil water is below drought thresholds. Through this work, we aim for a deeper understanding of this special type of forest edge, so to better assess its possible impacts on the railway system.

Stem radial growth is driven by the interaction between environmental conditions and tree physiological processes. As a result, tree rings serve as valuable natural archives, recording environmental information over time. In tropical forests, data on past climate variability and historical canopy greenness—an important indicator of forest health—are often limited in duration. Studying tree rings can thus provide essential insights into historical climate dynamics and canopy condition, helping us better predict the responses of tropical forests to global environmental changes. Here we present the first ring-width index chronologies (RWI) and normalized difference vegetation index (NDVI) (as a proxy of canopy greenness) time series of Zanthoxylum rhetsa (Roxb.) DC. from three moist forest sites in Bangladesh aligned along a gradient of increasing human disturbance. We compared historical annual radial growth rates with monthly, seasonal and annual climate data and seasonal NDVI values derived from high resolution satellite images. Our analyses showed that the growth of Z. rhetsa is primarily influenced by pre-monsoon temperatures and monsoon precipitation, with pre-monsoon climate signals becoming stronger in recent decades. The signal strength of the RWI chronologies, however, varied across study sites along the disturbance gradient, with stronger signals in the sites with low disturbance intensity. At the ecosystem level, canopy greenness (NDVI) was highly correlated with tree growth rates over the past two decades. NDVI showed high sensitivity to drought, particularly at drier sites. Global warming and drought are detrimental to forest health and thus limiting the carbon sequestration potential of moist tropical forests. By taking Zanthoxylum rhetsa as a model tree species in three Bangladeshi moist tropical forests we demonstrate how tree-ring analysis can be combined with remote sensing to reconstruct canopy dynamics for periods preceding the availability of satellite imagery for NDVI calculations that could be replicable to other tropical forests.

This study aims to strengthen dendroclimatic research in tropical dry forests by analyzing tree rings from Handroanthus chrysanthus and Bursera graveolens in southern Ecuador. We developed new dendrochronological records to determine the dendroclimatic potential of the species for evaluating the relationship between precipitation and tree growth. Chronologies were correlated with regional climate parameters, as well as with spatial patterns of Sea Surface Temperature (SST) anomalies. Besides dendroclimatic analyses, we propose enhancing Organic Code of the Environment (COA) regulations to promote the use of forest species with dendroclimatic potential, including Faculty number thirteen. Two tree-ring width chronologies were developed based on 39 H. chrysanthus and 53 B. graveolens trees. Tree growth shows strong correlations with precipitation during the rainy season, indicating that these species preserve reliable climatic information. This evidence supports the use of tree-ring data to inform climate adaptation and forest management strategies. Based on these findings, we propose incorporating a regulation within COA (Faculty no. 13) to "implement measures for the protection, sustainable management, and restoration of long-lived forest species with dendroclimatic potential in southern Ecuador." This enhancement can contribute to evidence-based environmental policy and strengthen climate adaptation strategies in the region.

Extreme droughts are increasing in frequency and intensity under climate change, posing growing threats to forest stability and carbon sequestration. Yet the relative roles of climatic conditions and intrinsic growth strategies in shaping drought resilience remain debated, particularly in monsoon-dominated tropical and subtropical regions. Here, we compiled a large tree-ring width dataset including 4418 cores from 2446 trees across 103 sites and four widespread pine species in Southeast Asia to investigate growth resilience and post-drought growth in response to extreme early growing-season droughts, and evaluated the relative importance of climate, drought sensitivity and growth attributes. Across species, radial growth was consistently constrained by early growing-season moisture availability, highlighting the importance of drought timing relative to cambial reactivation. Although species differed markedly in their extreme drought responses, most trees recovered to their mean non-drought growth levels within three years. Notably, drought sensitivity and intrinsic growth attributes (growth rate, size and age) emerged as dominant regulators of growth resistance and recovery. While long-term mean climatic conditions explained comparatively less variation in growth responses once drought sensitivity and growth attributes were accounted for. More drought-sensitive sites experienced lower resistance but stronger post-drought recovery. Our findings demonstrate that seasonal drought timing, growth sensitivity and tree growth attributes are important regulators of drought impacts and recovery dynamics in Southeast Asian pine forests. Explicitly incorporating growth attributes and growth sensitivity into forest growth assessments may improve predictions of drought impacts.

Drought-resilient native tree species are becoming increasingly vulnerable to the intensifying impacts of climate change. In this study, we conducted the first tree-ring stable carbon isotope and intrinsic water-use efficiency (iWUE) study of annually separated tree rings of Persian oak (Quercus brantii Lindl.) covering the period 1953–2022. The study sites are located at three different elevations in the Zagros Mountains. δ13C chronologies at all sites showed higher (less negative) δ13C values during the major drought events of 1964, 1984, and 2007–2008, followed by corresponding increases in their respective iWUE values. The highest iWUE values were observed at the high-elevation site. iWUE at the mid and high-elevation sites showed a pronounced increase from 2008 to 2022, suggesting a common physiological response of trees to increasing water limitation. Correlations with climate variables revealed significant negative relationships between winter and spring precipitation and δ13C, at mid and high-elevation sites. All three sites exhibited negative correlations with the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation-Evapotranspiration Index (SPEI) at accumulation periods ranging from 1 to 12 months, confirming the high sensitivity of Persian oak to hydroclimatic conditions during both the previous and current growing seasons, with particularly strong correlations observed at the mid and high-elevation sites. These patterns highlight the dominant role of drought in regulating stomatal conductance and carbon uptake, providing physiological evidence relevant to the observed oak dieback phenomena in the Zagros Mountains. Overall, δ13C variations in Persian oak are primarily driven by hydroclimatic factors (precipitation, relative humidity, and vapor pressure deficit), with timing and strength of these parameters varying in space and time among all studied sites. Our findings reveal that Persian oak exhibits different adaptive physiological strategies across the altitudinal transect, shifting from conservative water-use behaviour in more arid environments (low and high-elevations) to more flexible gas-exchange regulation under mesic conditions (mid elevations).

Climate change is increasing stress on forest ecosystems in arid and semi-arid regions, where tree growth is highly climate-sensitive. We examined climate controls on the tree-ring width (TRW) of Persian juniper (Juniperus polycarpos) at two semi-arid mountain sites in northeastern Iran, Qorkhūd Mountains and Hezar Masjed Mountain. The chronologies span 1231–2023 CE at Qorkhūd (793 years), and 1523–2021 CE at Hezar Masjed (499 years). Based on the EPS threshold (> 0.85), the reliable reconstruction intervals begin in 1612 CE and 1780 CE, respectively. Climate–growth analyses using CRU TS 4.03 and local synoptic records showed that Qorkhūd TRW responds positively to previous June–current May precipitation and negatively to temperature over the same period, whereas Hezar Masjed growth is mainly limited by previous October–current May precipitation. Linear regression models, validated by leave-one-out cross-validation, reconstructed precipitation for 1612–2022 at Qorkhūd (410 years; R² = 0.41) and 1786–2020 at Hezar Masjed (235 years; R² = 0.33). Both reconstructions show strong interannual to multi-decadal hydroclimatic variability. Synchronous dry years, including 1917, 2001, and 2008, and the wet year 1981, indicate regionally coherent precipitation anomalies. Recent decades include several of the most pronounced wet and dry events in the reconstructions, highlighting the occurrence of strong hydroclimatic extremes during the late twentieth and early twenty-first centuries. At Qorkhūd, the reconstruction also captures the observed calibration-period precipitation decline. Exploratory analyses indicate temporally variable links with North Atlantic indices, including NAO and AMO. These records provide a long, multi-site hydroclimatic context for northeastern Iran.

Water use strategies among coexisting species across successional gradients critically influence forest climate resilience and biodiversity conservation, but remain poorly understood for high-elevation regions. We investigated water use patterns of co-occurring species at three sites on the southeastern Tibetan Plateau and the eastern Himalayas using tree-ring oxygen isotopes (delta O-18(TR)), isotope-enabled model outputs (LMDZ4iso), and Roden-model-based mechanistic simulations. Statistical comparisons using Steiger's Z-tests and bootstrap resampling reveal clear temporal partitioning among species at the old-growth sites (Wache and Baima) and substantial overlap at the younger successional site (Xincuo). Specifically, at Wache, Larix griffithii predominantly used August-October soil moisture (September peak), whereas Picea spinulosa accessed July-October soil water (August peak). At Baima, Larix potaninii utilized July-October soil moisture with September peak uptake, while Abies georgei accessed June-October soil water peaking in July. Conversely, at the Xincuo site, species in the younger successional forest, including Abies georgei and Hippophae tibetana, exhibited significant water use overlap from June to September (July peak). Simulations based on the Roden framework indicate that physiological processes, including stomatal and biochemical fractionation, explain 92.1 %-99.8 % of the observed interspecific delta & sup1;O-8(TR) offset (similar to 3 parts per thousand). Nevertheless, delta & sup1;O-8(TR) chronologies still reliably capture interspecific differences in the seasonal timing of source-water uptake. Moreover, A. georgei acts as a flexible "bridge species," shifting from temporally partitioned water use in old-growth forests to overlapping resource use at the younger site, where shallow soils likely constrain niche differentiation. These results suggest that forest succession may enhance niche complementarity by increasing effective soil-water niche space. Such shifts in resource partitioning may play an important role in maintaining forest resilience under projected regional warming and precipitation change. Integrating delta & sup1;O-8(TR) observations with isotope-enabled model outputs and mechanistic simulations provides a useful framework for investigating species-level ecohydrological strategies in alpine forests.

Naturalized Acacia saligna has been widely introduced across dryland regions as a fast-growing species for landscape rehabilitation and soil stabilization. However, the ecological determinants governing its establishment, distribution, and growth performance remain insufficiently characterized. This study examined how key environmental variables and their interactions shape the distribution, abundance, and morphological traits of A. saligna populations, in Tigray, Ethiopia. Field surveys were conducted in 52 plots across five sites spanning an altitudinal range of 1960-2400 m and slope gradients of 5.2-41 %. Regression and correlation analyses were applied to identify environmental predictors of population density and growth performance. The occurrence of A. saligna was significantly influenced by tude at one site (P < 0.05), while abundance exhibited negative associations with soil pH, slope, sodium, magnesium, organic carbon, and bulk density. When data were pooled across sites, predominantly positive relationships emerged, except for slope, sand and clay content, available phosphorus, calcium, and magnesium. Population density was marily regulated by soil sodium, pH, cation exchange capacity (CEC), bulk density, and exchangeable potassium. phological traits, diameter at breast height (DBH), total height (Ht), crown diameter (CD), crown depth (CDp), crown area, showed strong positive intercorrelations (P < 0.05). Sand content positively influenced morphological velopment, likely through enhanced drainage and reduced compaction. Multiple regression and principal component analyses revealed that DBH was significantly affected by Ht, CDp, CEC, calcium availability, altitude, and slope, height exhibiting strong co-variation with DBH, CD, and CDp. These results demonstrate that A. saligna performance highly sensitive to site-specific edaphic and topographic conditions. Integrating such environmental diagnostics restoration planning is therefore essential to optimize species establishment, prevent maladaptation, and improve logical outcomes in dryland restoration programs.

Rapid climate change profoundly affects global forest ecosystems, though its impact varies regionally and among tree species. In this study, we employed high-temporal-resolution dendrometer data to assess species-specific responses to short-term dry spells in three major Central European tree species-Scots pine (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica)-across early, main, and late growth phases. We investigated how available soil water (ASW), soil water potential (SWP), and soil temperature (ST) regulate stem radial growth at sub-annual resolution. The soil moisture parameters ASW and SWP were identified as the most important pedoclimatic drivers of growth during short-term dry spells (Consecutive Dry days, CDD; precipitation <= 0.1 mm). We evaluated the effects of the timing and duration of dry spells on growth across the early, main, and late growth phases. The short-term dry spells affected trees differently, allowing us to identify the threshold of pedoclimatic variables for the two conifer species and Beech. The two conifer species showed significant stem circumference shrinkage across all growth phases. Significant shrinkage was observed on average after three CDD, with corresponding changes in ASW, SWP, and ST by -4.94 mm, -4.93 kPa, and +0.99 K. Beech, however, maintained growth during the early and main growth phases, reflecting a higher stability during short-term dry spells. Beech responded only to short-term dry spells in the late growth phase, experiencing a significant growth depression after seven CDD, with corresponding changes in ASW, SWP, and ST by -11.70 mm, 30.74 kPa, and 0.60 K, respectively. Our results highlight that late-summer short-term dry spells were particularly critical for conifers and beech, emphasizing the need to integrate soil-climate interactions when assessing intra-annual growth responses and pedoclimatic thresholds. Our findings support the early detection of critical moisture stress levels and provide guidance for adaptive forest management strategies to enhance forest resistance.

Abstract Iran’s long history of climate-related crises, primarily driven by droughts, has been intensified by ongoing climate change, placing forest ecosystems under increasing hydroclimatic stress. In recent decades, prolonged droughts combined with elevated atmospheric moisture deficits have reduced ecosystem resilience and increased vulnerability to degradation. To better understand long-term drought dynamics and their ecological impacts, we developed two 200-year chronologies (1821–2020) of tree-ring width (TRW) and stable oxygen isotope variations (δ1⁸O) from Juniperus polycarpos in the Hezar Masjed Mountains, northeastern Iran. The δ1⁸O record served as a proxy for atmospheric moisture conditions and was used to reconstruct growing-season (March–September) vapor pressure deficit (VPD). When combined with TRW in a multiple regression framework, this dual-parameter approach enabled reconstruction of the Standardized Precipitation-Evapotranspiration Index (SPEI07), representing cumulative growing-season hydroclimatic conditions related to soil moisture availability. This allows the differentiation of atmospheric and soil drought impacts on tree growth over two centuries. By classifying drought years into VPD-only, SPEI-only, and combined drought events, we found that drought conditions associated with reduced soil moisture availability (SPEI) exerted the strongest constraint on radial growth. Tree growth declined most strongly during severe SPEI droughts, followed by severe combined drought (COMB-D) years, whereas atmospheric drought alone (VPD-D) had a weaker and more transient effect. Growth typically recovered within two years following drought events. Analysis of long-term drought classifications (1821–2020) revealed a shift towards more intense droughts in recent decades, particularly in the frequency of severe VPD and combined drought years. Our findings highlight that tree growth in semi-arid mountain ecosystems is primarily limited by soil moisture availability, with atmospheric drought acting as an additional stressor when coinciding with soil moisture deficits. This study demonstrates the value of combining multiple tree-ring proxies to disentangle drought mechanisms and improve understanding of forest responses to climate change.

Climate change has affected forest ecosystems across the world over the past century. However, its impact is particularly high in the Himalayas due to increasing temperatures, extreme precipitation events, and regional droughts. In this context, a review of the current stage of research was deemed necessary to understand the adaptation of a key conifer species to climate variability in the Central Himalayas. Hence, we conducted a systematic review of published peer-reviewed journal articles addressing the growth performance of Abies spectabilis (D. Don) Spach in the Central Himalayas. From this review, three main patterns of climate response have emerged: a positive correlation of radial tree growth with temperature of the current and previous growing seasons, tree growth limitation by winter temperature, and by temperature or moisture in the pre-monsoon season. Overall, results indicate an elevation-dependent temperature sensitivity, a crucial role of moisture availability, and seasonal shifts in climate–growth relationships, reflecting the species’ adaptability to changing climate conditions. Our review revealed that studies on elevation-dependent adaptation of wood anatomical traits by A. spectabilis are still rare. The tree-ring growth of this species shows a complex response to climate variability, with increasing as well as decreasing growth trends across its distribution range.

Given growing concerns about global climate change, it is critical to understand both historical and current shifts in the hydroclimate, particularly in regions critically entwined with global circulation. The Tibetan Plateau, the Earth’s largest and highest plateau, is a nexus for global atmospheric processes, significantly influencing East Asian hydroclimate dynamics through the synergy of the Asian Monsoon and the Westerlies. Yet, understanding historical and recent hydroclimate fluctuations and their wide-ranging ecological and societal consequences remains challenging due to short instrumental observations and partly ambiguous proxy reconstructions. Here, we present a precisely-dated 3476-year precipitation reconstruction derived from tree-ring δ18O data on the Tibetan Plateau, representing one of the few multi-millennia-long annually-resolved terrestrial δ18O records to date. Our findings reveal that the 20th century drought extremes are severe within the past three millennia, and likely linked to the weakening of both the Asian Monsoon and Westerlies due to anthropogenic aerosol emissions. Additionally, our analyses identified three distinct stages (110 BC–AD 280, AD 330–770 and AD 950–1300) characterized by shifts toward arid hydroclimate conditions, corresponding to significant social unrest and dynasty collapses, which underscores the potential societal impacts of severe hydroclimatic shifts. An annually resolved 3476-year tree-ring record from the Tibetan Plateau reveals severe 20th century droughts and highlights the interplay between the Asian Monsoon and Westerlies. Droughts are often linked to the collapse of dynasties.

Moisture variability driven by climate change impacts soil moisture, affecting vegetation growth and cover, and enhances the morphodynamics, potentially increasing geohazard risks. Dendroclimatology and dendrogeomorphology techniques effectively quantifying the past moisture variability and geohazard episodes can be used to understand the climate-induced geohazard mechanisms in long-term. We reconstructed moisture variability and geohazard (rockfall) activity from the Kinnaur region in the Indian western Himalayas. The Western Disturbances (WDs) driven winter precipitation provides moisture crucial for tree growth during the spring and summer months. We developed a 463 year-long (1558-2021 CE) tree-ring width chronology (TRWC) of Cedrus deodara and performed correlation analysis with various climate variables. The significant positive correlation between TRWC and standardized precipitation evapotranspiration index (SPEI04) for the FebruaryMarch-April months revealed the combined effect of winter and spring month's water balance on tree growth. The SPEI04 reconstruction for the past 356 years showed that the study region experienced moderate to severe wet spring years between 1725 and 1757 CE, teleconnected to westerly circulation patterns, falling in the Little Ice Age (LIA) time frame. The dry spring phase after 1757 CE significantly teleconnects with a tropical ocean warming during late 19th and 20th centuries. We assessed the impact of moisture changes on the geohazard frequency and found good correspondence between years with dry spring months and rockfall activity. We observed an increase in geohazard activity since the mid-20th century, indicating an increasing vulnerability of slopes to ground failure. The spring and summer months are becoming more critical for tree growth and ground stability due to unprecedented temperature rise during the last century. Our findings provide a suitable baseline for adapted forest management, sustainability and ground stability measures under ongoing climate warming.

Increasing drought pressure under anthropogenic climate change may jeopardize the potential of tropical forests to capture carbon in woody biomass and act as a long-term carbon dioxide sink. To evaluate this risk, we assessed drought impacts in 483 tree-ring chronologies from across the tropics and found an overall modest stem growth decline (2.5% with a 95% confidence interval of 2.2 to 2.7%) during the 10% driest years since 1930. Stem growth declines exceeded 10% in 25% of cases and were larger at hotter and drier sites and for gymnosperms compared with angiosperms. Growth declines generally did not outlast drought years and were partially mitigated by growth stimulation in wet years. Thus, pantropical forest carbon sequestration through stem growth has hitherto shown drought resilience that may, however, diminish under future climate change.

The 8.2 and 4.2 ka BP abrupt climate events had significant impacts on Earth’s climate system. However, the spatio-temporal pattern of these events remains ambiguous in the East Asian summer monsoon (EASM) region. In this study, we collected thirteen previously published stalagmite δ18O sequences from the EASM region to assess spatial and temporal patterns of the 8.2 and 4.2 ka BP events during the ∼8.7–7.7 ka BP and ∼4.7–3.7 ka BP periods, respectively. Our results reveal that high-resolution stalagmite δ18O sequences from nearby locations exhibit strong consistency during the Holocene, thus capturing regional patterns of climate variability. Sensitivity experiments indicate that the temporal resolution and geographical location significantly affect the ability of the stalagmite δ18O sequences to record the 8.2 and 4.2 ka BP events. High-resolution stalagmite δ18O records from both northern and southern China show a distinct positive δ18O excursion corresponding with the 8.2 ka BP event, beginning at 8.23 ka BP and ending at 8.08 ka BP, thus lasting ∼150 yr, with an explained variance reaching ∼55

Mountain ecosystems are dynamic and highly sensitive to the negative impacts of climate change. Within this study, we conducted the first comprehensive dendrochronological, multi-site and multi-elevational study of Persian oak (Quercus brantii Lindl.) across the Zagros Mountains in Western Iran. Besides total ring-width (TRW), we separately measured earlywood width (EWW) and latewood width (LWW) to analyze climate impact on oak growth with sub-annual resolution. We found strong correlations between TRW, EWW, and LWW, as well as between the individual site chronologies. Several negative extreme events and long-term growth patterns were captured by all site chronologies, revealing an increase in the frequency of negative extreme events during recent decades (1930–2022). The standard chronologies exhibited strong climate signals representative for larger areas in West Asia and the Mediterranean region. Climate-growth response analyses indicated that winter precipitation is the most important growth-limiting factor, having a strong positive effect on the growth of the native oak species. Conversely, we found negative correlations between Tmax and Tmean and TRW, EWW, and LWW of Persian oak during the previous and current growth years. Correlations with various drought indices confirmed the strong negative impacts of dry periods on oak forests, particularly for the central and southern parts of the Zagros Mts. The very homogenous growth response across elevation and different microsite conditions emphasizes the dominant role of macroclimate on oak growth. Correlation analysis between annual and sub-annual ring-width parameters of Q. brantii and climate indices highlights the strong effect of large-scale teleconnection patterns on the Zagros oak forests. Our findings highlight the pivotal role of sufficient winter precipitation supply. Therefore, watershed management that promotes soil moisture conservation under current and expected future climate change is recommended to ensure long-term resilience of Persian oak forests.

Rainfall-related variables control tree radial growth of Detarium microcarpum and Tamarindus indica in West Africa's semi-arid savannas. West Africa constitutes a hotspot region for both land use change and climate change. Land use change, and high climate variability in this region negatively affect tree growth dynamics, ecosystem functioning and services. In the present study, we assessed the impacts of climate variability on tree growth of Detarium microcarpum Guill. Perr. and Tamarindus indica L., two Fabaceae woody species with high socio-economic significance in West Africa. In total, we collected 18 stem discs from dead trees of the two species in the South-Sudanian phytogeographic zone in Burkina Faso. The studied species showed well-defined growth ring-boundaries demarcated by marginal parenchyma bands. Cross-dating was successful within disc and within species, and enabled the construction of statistically robust tree-ring index chronologies. The chronologies spanned 45 years (1974 − 2019) and 30 years (1990 − 2019) for D. microcarpum and T. indica, respectively. We found a significant variation in tree growth rates (p-value < 0.05) between D. microcarpum (1.711 ± 0.491 mm year−1) and T. indica (2.613 ± 0.473 mm year−1). Pearson correlation analyses showed that the standard ring-width index for both species positively correlated with total annual precipitation amounts (p-value < 0.05) and major seasonal precipitation (p-value = 0.05). However, no significant correlation was found between ring-width index and temperature related variables. These findings support that precipitation controls tree growth of D. microcarpum and T. indica in the semi-arid savannas of West Africa. Consequently, a decrease in mean annual rainfall in West African region may negatively affect tree growth rate and stand dynamics of the studied species.