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Phytophthora cinnamomi (Pc) is an extremely destructive soil-borne pathogen of Asiatic origin responsible for "ink disease" in chestnut. This work assesses the adaptive potential to the impact of Pc of four Spanish populations of Castanea sativa undergoing different selection pressures. To explore the evolvability of C. sativa to Pc in the selected populations, parameters obtained from neutral and functional genetic diversity were compared with estimates of quantitative genetic variability. Nine expressed sequence tags-simple sequence repeat (EST-SSR) markers were selected and their transferability and polymorphism in 137 C. sativa individuals were evaluated. To test the potential of EST-SSR markers for early selection of Pc tolerant plant material, the offspring of selected individuals were challenged with Pc. Expressed sequence tags-simple sequence repeat markers and seedling life expectancy after Pc inoculation revealed significant different responses of C. sativa populations to Pc. The genetic variability observed within populations showed the potential response capacity of Spanish C. sativa populations to undergo fast adaptive evolution. The heritability value obtained for the "life expectancy" variable (h(2) = 0.21 +/- 0.11) indicated that selection for resistance to Pc is possible. Genetic patterns reflected two evolutionarily meaningful groupings of populations, corresponding to the different selective pressure of the oomycete between sites. The differentiation coefficient obtained through markers classified as under neutral selection (F-ST = 0.185) was lower than the quantitative genetic differentiation of "life expectancy" between C. sativa populations (Q(ST) = 0.682), providing evidence that selection acted spatially in a heterogeneous manner. A first link has been identified in trees between population structure and adaptive responses to pathogen-induced selection. The study identified one marker under positive selection that could be used in marker assisted selection to predict resistance to Pc in non-inoculated C. sativa trees.

Two months of drought or waterlogging conditions did not induce carbon starvation in Castanea sativa. Carbohydrate dynamics in treated plants provide evidence of why this species adapts well to dry but not to waterlogging conditions. Drought and flooding events, which cause water and oxygen deprivation in tree roots, are expected to occur more frequently due to climate change. The effects of drought and waterlogging on physiology, growth and N content of Castanea sativa Mill. were explored. Through a manipulative experiment, we induced growth-limiting conditions in C. sativa seedlings to identify differences in the dynamics of soluble sugars, starch and total non-structural carbohydrates (NSC) in leaves, stems and roots. Two-year-old seedlings were subjected for 2 months to regular watering, drought and waterlogging treatments. Drought and waterlogging induced similar effects on plants, including reduced stomatal conductance, net photosynthesis and growth. However, chlorophyll degradation was detected only in plants subjected to waterlogging. N content and C/N ratios differed between treatments and were highest in leaves of drought stressed plants and roots of control plants, respectively. Under drought, starch was rapidly depleted to yield soluble sugars and afterwards remained constant, and no change in total NSC was observed, probably allowing plants to reverse drought-induced xylem embolisms. Under waterlogging, a net gain of NSC over time in plant stems and roots was observed, suggesting that plants were unable to utilise them. This is the first study to report different strategies of carbon use in C. sativa trees subjected to drought and waterlogging. NSC dynamics in C. sativa plants provide evidence of why this species adapts well to dry but not to waterlogging conditions.

12 Pags.- 34Figs.- 3 Tabls., The negative impacts of drought on forest growth and productivity last for several years generating legacies, although the factors that determine why such legacies vary across sites and tree species remain unclear. We used an extensive network of tree‐ring width (RWI, ring‐width index) records of 16 tree species from 567 forests, and high‐resolution climate and normalized difference vegetation index (NDVI) datasets across Spain during the common period 1982‒2008 to test the hypothesis that climate conditions and growth features modulate legacy effects of drought on forests. Legacy effects of drought were calculated as the differences between detrended‐only RWI and NDVI series (i.e. after removing long‐term growth trends) and pre‐whitened RWI and NDVI series predicted by a model including drought intensity. Superposed Epoch Analysis (SEA) was used to estimate whether legacy effects differed from random. Finally, legacy effects were related to water balance, growth persistence and variability, and tree species identity. We found a widespread occurrence of drought legacy effects on both RWI and NDVI, but they were seldom significant. According to SEA, first‐year drought legacies were negative and different from random in 9% and 5% of the RWI and NDVI series respectively. The number of significant second‐ and third‐year legacies was substantially lower. Differences between RWI and NDVI legacies indicate that canopy greenness and radial growth responses to drought are decoupled. We found variations in legacies between tree species with gymnosperms presenting larger first‐year drought legacies than angiosperms, which were exposed to less severe droughts. Greater growth variability can explain the presence of first‐year RWI legacies in gymnosperms from dry sites despite that the relationship between growth variability and legacies was complex. Synthesis. Accounting for species and site responses to drought provides a better understanding of the magnitude and duration of drought legacies on forest growth and productivity. Despite the widespread occurrence of growth reductions in the years during and after drought occurrence, significant legacies were not very common, mostly lasted one year, and were more widespread in gymnosperms. These are relevant factors to be considered in the future when studying the consequences of drought on forest productivity and tree growth., This study was financially supported by: Xunta de Galicia, Grant/Award Number: PGIDIT06PXIB502262PR, GRC GI‐1809; INIA, Grant/Award Number: RTA2006‐00117; CANOPEE, 2014‐2020‐FEDER funds; and Spanish Science Ministry: RTI2018‐096884‐B‐C31, RTI2018‐096884‐B‐C33, AGL2017‐83828‐C2‐2R and ENV4‐CT97‐0641 projects. GSB was supported by a ‘Juan de la Cierva Formación’ grant from MINECO (FJCI 2016‐30121). This research was supported by the BERC 2018‐2021 program, and by the Spanish Ministry of Science, Innovation and Universities through the BC3 María de Maeztu excellence accreditation (MDM‐2017‐0714) and the IBERYCA (CGL2017‐84723‐P) project. R.S.S. was supported by VULBOS project (UPO‐1263216, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014‐2020), and A.H. by PinCaR project (UHU‐1266324, FEDER Funds, Andalusia Regional Government, Consejería de Economía, Conocimiento, Empresas y Universidad 2014‐2020). K.N. was supported by the Ministry of Education, Science and Sports (Republic of Slovenia, Raziskovalci‐2.1‐UL‐BF‐ C3330‐19‐952011).

21 Pags.- 5 Figs.- 1 Appendix. - Suppl. Data., This study links tree-ring growth and gross primary production for a variety of forest types under different environmental conditions across Spain. NOAA-AVHRR satellite imagery data were combined with dendrochronological records and climate data at a fine spatial resolution (1.21 km2) to analyze the interannual variability of tree-ring growth and vegetation activity for different forest biomes from 1981 to 2015. Specifically, we assessed the links between tree-ring width indices (TRWi), the Normalized Difference Vegetation Index (NDVI) and a variety of environmental conditions, represented by climatic variables (air temperature, precipitation, evapotranspiration and water balance) and elevation. The impact of these variables on tree growth was assessed by means of the Predictive Discriminant Analysis (PDA). Results reveal a general positive and significant relationship between inter-annual variability of the NDVI at a high spatial resolution (1.21 km2) and tree-ring growth. Maximum correlations between NDVI and tree-ring growth were recorded when cumulative NDVI values were considered, in some cases covering long time periods (6–10 months), suggesting that tree growth is mainly related to Gross Primary Production (GPP) at annual scale. The relationship between tree-ring growth and inter-annual variability of the NDVI, however, strongly varies between forest types and environmental conditions., This work was supported by the research projects CGL2014-52135-C03-01, CGL2015-69186-C2-1-R, CGL2015-69985-R, CGL2013-48843-C2-1-R, AGL2014-53822-C2-1-R, (BFU2010-21451), PCIN-2015-220, CGL2016-81706-REDT and CGL2017-82216-R financed by the Spanish Commission of Science and Technology and FEDER, 1560/2015: Herramientas de monitorización de la vegetación mediante modelización ecohidrológica en parques continentales financed by the Red de Parques Nacionales, IMDROFLOOD financed by the Water Works 2014 co-funded call of the European Commission, CROSSDRO financed by the AXIS (Assessment of Cross(X) – sectorial climate Impacts and pathways for Sustainable transformation) JPI-Climate co-funded call of the European Commission and INDECIS, which is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462). Financed by the Spanish Commission of Science and Technology and FEDER, and INDECIS, which is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Union (Grant 690462). Natalia Martin-Hernandez was supported by a doctoral grant by the Aragon Regional Government, Marina Peña-Gallardo was granted by the Spanish Ministry of Economy and Competitiveness and Miquel Tomas-Burguera was supported by a doctoral grant by the Spanish Ministry of Education, Culture and Sport. Raúl Sánchez-Salguero, Antonio Gazol and Gabriel Sangüesa-Barreda were supported by Postdoctoral grants (IJCI-2015-25845, MINECO-FPDI 2013-16600 and FJCI 2016-30121, respectively; FEDER funds). This work also benefited from funding from Xunta de Galicia (PGIDIT06PXIB502262PR, GRC GI-1809, ROCLIGAL-10MDS291009PR), INIA (RTA2006-00117), and Interreg V-A POCTEFA (CANOPEE, 2014-2020-FEDER funds) projects.

Nut production by the European sweet chestnut (Castanea sativa Mill.) in grafted orchards is under threat of increased drought stress associated with current global warming. To explore whether drought tolerance in C. sativa could be improved using drought tolerant scions and rootstocks, trees from humid (H) and xeric (X) populations in Spain were used to generate intra-family (H/H and X/X) and reciprocal inter-location (X/H and H/X) grafts. We studied the effects of the (i) scion, (ii) rootstock and (iii) the grafting itself as a wounding stress on the vegetative budbreak, secondary growth and drought tolerance of C. sativa trees. Drought tolerance was assessed by measuring leaf gas exchange, chlorophyll fluorescence, water status and leaf wilting two weeks after water deprivation. Hormone (ABA, SA, JA and JA-Ile) and proline quantification in tree leaves and fine roots were assessed, as well as tree and scion mortality. Rootstocks and scions of xeric origin induced earlier flushing and improved drought tolerance of scions and rootstocks of humid origin. Tree mortality after drought was 57 % lower in H/X than in H/H trees, and scion loss after drought was 47 % lower in H/X than in X/H trees. The ‘grafting’ (i.e., wounding) effect delayed vegetative budbreak and reduced secondary growth of trees but did not predispose trees to drought. We report for the first time differences in hormone and proline content in leaves and fine roots of chestnut trees of humid and xeric origins exposed to drought. The results suggest the use of scions and rootstocks from xeric areas to improve drought tolerance in chestnut.

International audience; AbstractKey messageIncreased tolerance toPhytophthora cinnamomiwas observed in small-sized offspring of ink-diseased chestnut trees, suggesting that a virulent pathogen can trigger a defence response of trees in the subsequent generation. Increased tolerance to water stress was not observed in offspring of chestnut trees.ContextIn sweet chestnut (Castanea sativa Miller), P. cinnamomi Rands is responsible for the widespread and destructive ink disease.AimsWe investigated if the susceptibility of C. sativa to water stress and P. cinnamomi depends on the health status of mother trees.MethodsPlants were grown from seeds collected from healthy and ink-diseased chestnut trees. Leaf wilting after drought exposure and plant mortality after pathogen inoculation were assessed.ResultsOffspring of ink-diseased trees had poorer performance in plant height and root biomass than offspring of healthy trees, with allocation of biomass to seeds mediating this effect. Leaf wilting due to water stress was similar in offspring of healthy and P. cinnamomi-infected trees. However, increased tolerance to P. cinnamomi was observed in small-sized seedlings, suggesting that tolerance in C. sativa may involve growth costs. This is the first report of increased tolerance to P. cinnamomi in plants germinating from a diseased tree.ConclusionThe results suggest that an invasive pathogen can regulate the performance and prime a defence response of a forest tree species in the subsequent generation, and generate conflicting selection pressures related to plant size.

Phytophthora cinnamomi (Pc) is a dangerous pathogen that causes root rot (ink disease) and threatens the production of chestnuts worldwide. Despite all the advances recently reported at molecular and physiological level, there are still gaps of knowledge that would help to unveil the defence mechanisms behind plant-Pc interactions. Bearing this in mind we quantified constitutive and Pc-induced stress-related signals (hormones and metabolites) complemented with changes in photosynthetic related parameters by exploring susceptible and resistant Castanea spp.-Pc interactions. In a greenhouse experiment, five days before and nine days after inoculation with Pc, leaves and fine roots from susceptible C. sativa and resistant C. sativa × C. crenata clonal 2-year-old plantlets were sampled (clones Cs14 and 111-1, respectively). In the resistant clone, stomatal conductance (gs) and net photosynthesis (A) decreased significantly and soluble sugars in leaves increased, while in the susceptible clone gs and A remained unchanged and proline levels in leaves increased. In the resistant clone, higher constitutive content of root SA and foliar ABA, JA and JA-Ile as compared to the susceptible clone were observed. Total phenolics and condensed tannins were highest in roots of the susceptible clone. In response to infection, a dynamic hormonal response in the resistant clone was observed, consisting of accumulation of JA, JA-Ile and ABA in roots and depletion of total phenolics in leaves. However, in the susceptible clone only JA diminished in leaves and increased in roots. Constitutive and Pc-induced levels of JA-Ile were only detectable in the resistant clone. From the hormonal profiles obtained in leaves and roots before and after infection, it is concluded that the lack of effective hormonal changes in C. sativa explains the lack of defence responses to Pc of this susceptible species. published

Quantifying climate-growth associations is needed to evaluate how forest productivity will respond to climate change. Year-to-year fluctuations in forest productivity and radial growth are partly explained by local climatic conditions driven by large-scale atmospheric patterns. This is illustrated by Iberian forests in the western Mediterranean Basin, which are subjected to complex climatic and atmospheric influences such as Atlantic and Mediterranean cyclogenesis. The North Atlantic Oscillation (NAO) is one of the major atmospheric circulation patterns affecting Iberian forests since positive winter NAO phases lead to dry and warm conditions. The Western Mediterranean Oscillation (WeMO) may also explain Iberian forest growth in some areas since this index captures Mediterranean cyclogenesis and WeMO negative phases are linked to warm and wet spring to summer conditions. Here, we analyze the associations between atmospheric patterns, climate and tree growth and we determine if they are changing through time. We use dendrochronology to relate radial growth of four tree species (Pyrenean oak, Sweet chestnut, Maritime pine and Scots pine) growing in western Spain to climate conditions and the NAO and WeMO indices. Winter and early spring temperatures increased since the 1950s in the area whereas the negative association between winter precipitation and the NAO strengthened since then. However, mean temperature rise was particularly evident since the 1970s. Growth was reduced by dry conditions during the growing season (spring and summer), but also by cold and dry conditions during the previous autumn and winter. This explains why the NAO January and the WeMo April indices were negative to growth of three species excluding Pyrenean oak. The early 1970s reflected an inflection point in the instability of climate-growth associations in the study area. We conclude that the winter NAO is a relevant driver of forest growth in the western Iberian Peninsula forests but additional atmospheric patterns (WeMO) also affect, albeit to a minor extent, these forests.

Producción Científica, Drought is one of the key natural hazards impacting net primary production and tree growth in forest ecosystems. Nonetheless, tree species show different responses to drought events, which make it difficult to adopt fixed tools for monitoring drought impacts under contrasting environmental and climatic conditions. In this study, we assess the response of forest growth and a satellite proxy of the net primary production (NPP) to drought in peninsular Spain and the Balearic Islands, a region characterized by complex climatological, topographical, and environmental characteristics. Herein, we employed three different indicators based on in situ measurements and satellite image-derived vegetation information (i.e., tree-ring width, maximum annual greenness, and an indicator of NPP). We used seven different climate drought indices to assess drought impacts on the tree variables analyzed. The selected drought indices include four versions of the Palmer Drought Severity Index (PDSI, Palmer Hydrological Drought Index (PHDI), Z-index, and Palmer Modified Drought Index (PMDI)) and three multi-scalar indices (Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Precipitation Index (SPI), and Standardized Precipitation Drought Index (SPDI)). Our results suggest that—irrespective of drought index and tree species—tree-ring width shows a stronger response to interannual variability of drought, compared to the greenness and the NPP. In comparison to other drought indices (e.g., PDSI), and our results demonstrate that multi-scalar drought indices (e.g., SPI, SPEI) are more advantageous in monitoring drought impacts on tree-ring growth, maximum greenness, and NPP. This finding suggests that multi-scalar indices are more appropriate for monitoring and modelling forest drought in peninsular Spain and the Balearic Islands., Ministerio de Economía projects: (CGL2015-69186-C2-1-R (Fundiver)), (CGL2015-69985-R (CLIMED)),( CGL2013-48843-C2-1-R (CoMo-ReAdapt)),( AGL2014-53822-C2-1-R (SATIVA)),( XIRONO (BFU2010-21451)),( CGL2014-52135-C03-01), (PCIN-2015-220), and (CGL2016-81706-REDT (Ecometas Network)), (1560/2015 (ECOHIPRO)), Xunta de Galicia, projects:(PGIDIT06PXIB502262PR, GRC GI-1809, ROCLIGAL-10MDS291009PR), INIA (RTA200600117) e Interreg V-A POCTEFA (CANOPEE, 2014-2020-fondos FEDER), Ministerio de Economía y Empresa, postdoctoral grants (MINECO-FPDI 2013-16600; fondos FEDER), Postdoctoral grants (IJCI-2015-25845)

12 pages, 4 figures, 4 tables, Key message: Quercus secondary forests show a gradual transition toward mixed forests, with sweet chestnut ( Castanea sativa ) becoming increasingly abundant in the western Spanish Central System. Additionally, in chestnut-dominated stands, it shows a certain resistance to competitive displacement by Quercus pyrenaica . Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs. Context: Sweet chestnut, Castanea sativa, is a component of European broadleaf forests and is one of the most managed trees. Due to a reduction in cultural inputs, chestnut-dominated stands tend to be invaded by other species, and it is unclear how chestnut is able to persist in natural mixed forests. Aims: Our work aimed to identity the main factors that limit the establishment of C. sativa and to analyze the recruitment and mortality processes of C. sativa trees. Methods: The age, growth ring patterns, regeneration density, and the spatial structure of trees and saplings in 11 plots in the Spanish Central System were analyzed. Results: Chestnut seedling density increased with C. sativa basal area, but transition toward the sapling stage appeared limited owing to light availability. In Quercus pyrenaica secondary forests, sparse canopies did not constrain chestnut regeneration, and in old chestnut stands, C. sativa showed a certain resistance to competitive displacement. By contrast, mixed young coppices showed a high mortality, most likely due to competition with other vigorous resprouters. Conclusion: Quercus secondary forests showed a gradual transition toward mixed forests with sweet chestnut becoming increasingly more abundant. In old stands, C. sativa is likely to persist under a gap-phase mode of regeneration. Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs, This study was funded by research Grants for Master’s projects administered by the Master’s program in Biology and Conservation of Biodiversity of the University of Salamanca, Spain

In the Mediterranean region, over the past few centuries human activity has modeled the landscape, leading to forest degradation. However, as in many parts of the European continent since the second half of the twentieth century, the Iberian Peninsula has been subject to a substantial degree of land abandonment that has led to the expansion of important secondary forests. One of the dominant tree species in the transitional forests of mountain areas between the Mediterranean and Euro-Siberian regions of the Iberian Peninsula is the deciduous oak, Quercus pyrenaica Willd. The main objectives of the present work were to study the mode of regeneration and forest dynamics of Q. pyrenaica in several types of stands: young forests, mature and previously perturbed forests, and abandoned Pinus reforestations. With this in mind we established eight plots in the mountain range of the Sierra de Francia–Quilamas, in the west subdivision of the Spanish Central System. We analyzed the age and dbh distributions, regeneration density, and the spatial structure of trees and saplings. Young Q. pyrenaica stands were seen to show episodic recruitment after land abandonment consistent with a ‘catastrophic’ mode of regeneration. These stands were characterized by unimodal age-cohorts, with tree recruitment dropping drastically as the canopy developed and closed in, except at some study sites where the more shade-tolerant Castanea sativa was found. Older and previously disturbed Q. pyrenaica stands showed bimodal age cohorts, the young ones exhibiting a clumped pattern associated with canopy gaps and/or a lower tree density of the older cohort. In abandoned Pinus reforestations, the recruitment of Q. pyrenaica was also associated with canopy openings. These findings show that Q. pyrenica also undergoes a gap-phase mode of regeneration. An abundant regeneration of Q. pyrenaica could be found at all the stands, guaranteeing the persistence of seedling banks (but a scarcity or lack of saplings) under closed forests, until canopy gaps may allow some Q. pyrenaica individuals to grow and reach the main canopy.

16 Pags.- 3 Tabls.- 5 Figs., Forecasted increase drought frequency and severity may drive worldwide declines in forest productivity. Species‐level responses to a drier world are likely to be influenced by their functional traits. Here, we analyse forest resilience to drought using an extensive network of tree‐ring width data and satellite imagery. We compiled proxies of forest growth and productivity (TRWi, absolutely dated ring‐width indices; NDVI, Normalized Difference Vegetation Index) for 11 tree species and 502 forests in Spain corresponding to Mediterranean, temperate, and continental biomes. Four different components of forest resilience to drought were calculated based on TRWi and NDVI data before, during, and after four major droughts (1986, 1994–1995, 1999, and 2005), and pointed out that TRWi data were more sensitive metrics of forest resilience to drought than NDVI data. Resilience was related to both drought severity and forest composition. Evergreen gymnosperms dominating semi‐arid Mediterranean forests showed the lowest resistance to drought, but higher recovery than deciduous angiosperms dominating humid temperate forests. Moreover, semi‐arid gymnosperm forests presented a negative temporal trend in the resistance to drought, but this pattern was absent in continental and temperate forests. Although gymnosperms in dry Mediterranean forests showed a faster recovery after drought, their recovery potential could be constrained if droughts become more frequent. Conversely, angiosperms and gymnosperms inhabiting temperate and continental sites might have problems to recover after more intense droughts since they resist drought but are less able to recover afterwards., This study was financially supported by the Spanish Ministry of Economy projects: CGL2015‐69186‐C2‐1‐R (Fundiver), CGL2015‐69985‐R (CLIMED), CGL2013‐48843‐C2‐1‐R (CoMo‐ReAdapt), AGL2014‐53822‐C2‐1‐R (SATIVA), XIRONO (BFU2010‐21451), CGL2014‐52135‐C03‐01, PCIN‐2015‐220, and CGL2016‐81706‐REDT (Ecometas Network). The study was also funded by IMDROFLOOD (Water Works 2014, EC) and INDECIS (European Research Areas for Climate Services) projects. This work also benefited from funding from Xunta de Galicia (PGIDIT06PXIB502262PR, GRC GI‐1809, ROCLIGAL‐10MDS291009PR), INIA (RTA2006‐00117), and Interreg V‐A POCTEFA (CANOPEE, 2014‐2020‐FEDER funds) projects. RSS and AG were supported by Postdoctoral grants (IJCI‐2015‐25845 and MINECO‐FPDI 2013‐16600; FEDER funds).

The European Dendroecologial Fieldweek (EDF) provides an intensive learning experience in tree-ring research that challenges any participant to explore new multidisciplinary dendro-sciences approaches within the context of field and laboratory settings. Here we present the 25th EDF, held in Asturias, NW Spain, in summer 2014. The course, with 33 participants and 10 instructors from 18 countries included advanced training in dendrochronology skills, an overview of tree-ring broad fields and methodological basics to deal with specific research questions as well as applied advanced micro-projects in dendroarchaeology (DAR), dendroclimatology (DCL), dendrogeomorphology (DGM), forest dynamic (FD) and plant anatomy (PA). The results demonstrated the potential of tree-ring research in the Asturias region. The DAR group researched archaeological samples from different contexts (Oviedo cathedral choir stalls, Segovia cathedral roof timbers, Ribadeo shipwreck ship timbers and Bronze Age site charcoal) and explored the supply of wood in different periods. The DCL group established that the Quercus robur and Castanea sativa ring-width measurements show weak climate-growth correlations, where for many trees this is likely caused by management. The strength of the climatic signal could be enhanced using undisturbed settings. The DGM group found that Corylus avellana and Salix spp. are challenging species for dendrogeomorphological studies. Debris-flow events were detected by the presence of tension wood, growth reduction and scars, and their incidences were also supported by local meteorological data. The FD group found that tree growth decreases with increasing competition, a pattern more pronounced in C. sativa than in Pinus sylvestris forest plantations. The results indicate that wood production could be increased by applying thinning treatments on C. sativa. The PA group showed that xylem conduits and phloem area are organized according to the common needs for water supply to leaves and obtain photosynthetic products, regardless site growing conditions for P. sylvestris and Tusilago farfara. In conclusion, this EDF has been a model for interdisciplinary research and international collaboration that has demonstrated that high-quality research and education can be conducted within one week. The EDFs provide an important service to the dendrochronological community and demonstrate the usefulness of this educational-scientific and multi-cultural experience.