Dendroanatomy: a new approach to sharpen the focus on the climatic drivers of tree growth in the Mediterranean.

Climate change is the biggest challenge of our time and the Mediterranean basin one of the hot spots where its effects are already tangible. For this region most climate models predict higher temperatures and diminishing rainfall with likely longer and more frequent drought events which represent the principal threat for tree species, affecting growth, mortality and composition of future forest. Using cutting edge techniques for sample preparation and microscopic image analysis, this dissertation assessed the growth responses of xylem anatomy to climatic constraints. This dendroanatomical approach permits the long-term retrospective analysis of intra-annual growth information permanently fixed and archived in secondary xylem tissue. Wood anatomical results were contrasted and complemented by the use of many other methodologies like xylogenesis, dendrometers and non-structural carbohydrate analysis. The main species targeted was Aleppo pine (Pinus halepensis). Its growth pattern was firstly compared with another coexisting conifer (Juniperus thurifera) and their correlations with climate variables evaluated. Afterwards, the bimodal growth pattern shown by this species was assessed in two distinct climatic zones (continental vs. oceanic). Finally, three groups of trees under different irrigation treatments were compared. The dendroanatomical analysis of all three stages comprised always a time span of about 40 years, while the complementary methodologies varied according to the different experimental settings. Applying this dendroanatomical approach it was possible to link xylogenesis with wood anatomy on a decadal-long time scale and explain the climatic correlations that drive the bimodal growth patterns commonly reported in Mediterranean species. In addition, it was possible to disentangle the climatic cues influencing the growth plasticity of Aleppo pines under different conditions: where climate is milder the bimodality in growth is stronger. At the end, the irrigation trial highlighted that growth performances and xylem anatomy can be significantly affected by water availability and that trees tend to maintain a fairly good coordination between C supply and demand even during prolonged drought. This dissertation improves the general understanding of how higher temperatures and drier conditions will impact and influence the growth and distribution of the Aleppo pine. As one of the most common tree species of the Mediterranean region, the results of these studies can help to understand and predict the future forest dynamics under an uncertain climatic future

The Italian TREETALKER NETWORK (ITT-Net): continuous large scale monitoring of tree functional traits and vulnerabilities to climate change

20openItalian coauthor/editorThe Italian TREETALKER NETWORK (ITT-Net) aims to respond to one of the grand societal challenges: the impact of climate changes on forests ecosystem services and forest dieback. The comprehension of the link between these phenomena requires to complement the most classical approaches with a new monitoring paradigm based on large scale, single tree, high frequency and long-term monitoring tree physiology, which, at present, is limited by the still elevated costs of multi-sensor devices, their energy demand and maintenance not always suitable for monitoring in remote areas. The ITT-Net network will be a unique and unprecedented worldwide example of real time, large scale, high frequency and long-term monitoring of tree physiological parameters. By spring 2020, as part of a national funded project (PRIN) the network will have set 37 sites from the north-east Alps to Sicily where a new low cost, multisensor technology “the TreeTalker®” equipped to measure tree radial growth, sap flow, transmitted light spectral components related to foliage dieback and physiology and plant stability (developed by Nature 4.0), will monitor over 600 individual trees. A radio LoRa protocol for data transmission and access to cloud services will allow to transmit in real time high frequency data on the WEB cloud with a unique IoT identifier to a common database where big data analysis will be performed to explore the causal dependency of climate events and environmental disturbances with tree functionality and resilience. With this new network, we aim to create a new knowledge, introducing a massive data observation and analysis, about the frequency, intensity and dynamical patterns of climate anomalies perturbation on plant physiological response dynamics in order to: 1) characterize the space of “normal or safe tree operation mode” during average climatic conditions; 2) identify the non-linear tree responses beyond the safe operation mode, induced by extreme events, and the tipping points; 3) test the possibility to use a high frequency continuous monitoring system to identify early warning signals of tree stress which might allow to follow tree dynamics under climate change in real time at a resolution and accuracy that cannot always be provided through forest inventories or remote sensing technologies.openCastaldi, S.; Antonucci, S.; Asgharina, S.; Battipaglia, G.; Belelli Marchesini, L.; Cavagna, M.; Chini, I.; Cocozza, C.; Gianelle, D.; La Mantia, T.; Motisi, A.; Niccoli, F.; Pacheco Solana, A.; Sala, G.; Santopuoli, G.; Tonon, G.; Tognetti, R.; Zampedri, R.; Zorzi, I.; Valentini, R.Castaldi, S.; Antonucci, S.; Asgharina, S.; Battipaglia, G.; Belelli Marchesini, L.; Cavagna, M.; Chini, I.; Cocozza, C.; Gianelle, D.; La Mantia, T.; Motisi, A.; Niccoli, F.; Pacheco Solana, A.; Sala, G.; Santopuoli, G.; Tonon, G.; Tognetti, R.; Zampedri, R.; Zorzi, I.; Valentini, R

Growth rings show limited evidence for ungulates' potential to suppress shrubs across the Arctic

Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5 degrees C-9 degrees C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates' potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions

Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic

Global warming has pronounced effects on tundra vegetation, and rising mean temperatures increase plant growth potential across the Arctic biome. Herbivores may counteract the warming impacts by reducing plant growth, but the strength of this effect may depend on prevailing regional climatic conditions. To study how ungulates interact with temperature to influence growth of tundra shrubs across the Arctic tundra biome, we assembled dendroecological data from 20 sites, comprising 1153 individual shrubs and 223 63 annual growth rings. Evidence for ungulates suppressing shrub radial growth was only observed at intermediate summer temperatures (6.5 ◦C–9 ◦C), and even at these temperatures the effect was not strong. Multiple factors, including forage preferences and landscape use by the ungulates, and favourable climatic conditions enabling effective compensatory growth of shrubs, may weaken the effects of ungulates on shrubs, possibly explaining the weakness of observed ungulate effects. Earlier local studies have shown that ungulates may counteract the impacts of warming on tundra shrub growth, but we demonstrate that ungulates’ potential to suppress shrub radial growth is not always evident, and may be limited to certain climatic conditions.Research Council of Norwayhttp://iopscience.iop.org/1748-9326dm2022Mammal Research InstituteZoology and Entomolog

Dendroanatomy: a new approach to sharpen the focus on the climatic drivers of tree growth in the Mediterranean.

Climate change is the biggest challenge of our time and the Mediterranean basin one of the hot spots where its effects are already tangible. For this region most climate models predict higher temperatures and diminishing rainfall with likely longer and more frequent drought events which represent the principal threat for tree species, affecting growth, mortality and composition of future forest. Using cutting edge techniques for sample preparation and microscopic image analysis, this dissertation assessed the growth responses of xylem anatomy to climatic constraints. This dendroanatomical approach permits the long-term retrospective analysis of intra-annual growth information permanently fixed and archived in secondary xylem tissue. Wood anatomical results were contrasted and complemented by the use of many other methodologies like xylogenesis, dendrometers and non-structural carbohydrate analysis. The main species targeted was Aleppo pine (Pinus halepensis). Its growth pattern was firstly compared with another coexisting conifer (Juniperus thurifera) and their correlations with climate variables evaluated. Afterwards, the bimodal growth pattern shown by this species was assessed in two distinct climatic zones (continental vs. oceanic). Finally, three groups of trees under different irrigation treatments were compared. The dendroanatomical analysis of all three stages comprised always a time span of about 40 years, while the complementary methodologies varied according to the different experimental settings. Applying this dendroanatomical approach it was possible to link xylogenesis with wood anatomy on a decadal-long time scale and explain the climatic correlations that drive the bimodal growth patterns commonly reported in Mediterranean species. In addition, it was possible to disentangle the climatic cues influencing the growth plasticity of Aleppo pines under different conditions: where climate is milder the bimodality in growth is stronger. At the end, the irrigation trial highlighted that growth performances and xylem anatomy can be significantly affected by water availability and that trees tend to maintain a fairly good coordination between C supply and demand even during prolonged drought. This dissertation improves the general understanding of how higher temperatures and drier conditions will impact and influence the growth and distribution of the Aleppo pine. As one of the most common tree species of the Mediterranean region, the results of these studies can help to understand and predict the future forest dynamics under an uncertain climatic future.Il cambiamento climatico è la più grande sfida dei nostri tempi ed i suoi effetti sono già tangibili in varie aree come ad esempio il bacino del Mediterraneo. La maggior parte dei modelli climatici prevedono in questa regione un contemporaneo innalzamento delle temperature e diminuzione delle precipitazioni con conseguente aumento di durata e frequenza degli eventi siccitosi. Questi eventi rappresentano la principale minaccia per le specie arboree, possono infatti influenzare la crescita, la mortalità e modificare la composizione delle future foreste. Grazie all’utilizzo di tecniche all’avanguardia nella preparazione dei campioni ed analisi microscopica delle immagini, questa tesi ha individuato le risposte anatomiche all’accrescimento in condizioni climatiche limitanti. Questo approccio dendroanatomico consente l'analisi retrospettiva a lungo termine delle informazioni di accrescimento intra-annuale, permanentemente impresse e cronologicamente archiviate nel legno. I risultati dell’analisi anatomica sono stati comparati e complementati dall'utilizzo di molte altre metodologie come: xilogenesi, dendrometri e analisi dei carboidrati non strutturali. Il pino d'Aleppo (Pinus halepensis) è la principale specie considerata in questo studio. Inizialmente, il suo modello di crescita è stato paragonato a quello di un’ altra conifera coesistente (Juniperus thurifera) e sono state valutate le correlazioni con le variabili climatiche. Successivamente, il modello di crescita bimodale mostrato da questa specie è stato analizzato in due distinte zone climatiche (continentale o oceanica). Infine, sono stati confrontati tre gruppi di pini d’Aleppo sottoposti a diversi trattamenti di irrigazione. In tutte e tre le fasi precedenti, l’analisi dendroanatomica ha sempre considerato un intervallo di tempo di circa 40 anni, mentre le metodologie complementari sono variate in base alle diverse impostazioni sperimentali. Applicando questo approccio dendroanatomico è stato possibile collegare la xilogenesi con l'anatomia del legno su una scala decennale ed a lungo termine e spiegare le correlazioni climatiche che guidano i modelli bimodali di crescita che vengono comunemente riportati per le specie mediterranee. Inoltre, è stato possibile individuare i fattori climatici che influenzano la plasticità xilematica e di conseguenza l’accrescimento dei pini d'Aleppo in diverse condizioni climatiche: dove il clima è mite la bimodalità nella crescita è più forte. Infine, lo studio di irrigazione ha evidenziato che la crescita e l'anatomia xilematica possono essere influenzate in modo significativo dalla disponibilità idrica e che le piante arboree tendono a mantenere un buon coordinamento tra domanda ed offerta di carbonio anche durante periodi di siccità prolungata. Questa tesi migliora la comprensione generale di come l’innalzamento delle temperature e l’aumento degli eventi siccitosi impatteranno e influenzeranno la crescita e la distribuzione del pino Aleppo. Essendo il pino d’Aleppo una delle specie arboree più comuni nella regione mediterranea, i risultati di questa tesi possono contribuire a comprendere e prevedere le future dinamiche forestali in un futuro climatico incerto

INTRA-ANNUAL CLIMATIC DRIVERS OF GROWTH AND WOOD ANATOMY AGREE WITH XYLOGENESIS PATTERNS IN TWO MEDITERRANEAN CONIFERS

In Mediterranean continental climates, trees face a double climatic stress, cold winters and dry summers. Improved understanding of the different climate sensitivity in coexisting tree species may help to better predict future forest dynamics in a global warming scenario. We measured wood anatomical features as related to weekly- to monthly-resolved weather records to determine the main climatic drivers of wood formation at intra-annual scales. Two coexisting Mediterranean conifers (Pinus halepensis and Juniperus thurifera) were considered to measure tree-ring width and anatomical variables (lumen transversal area and cell-wall thickness) using the software ROXAS. We related these variables with local climatic data (mean minimum and maximum temperatures, precipitation, soil moisture deficit) for the period 1970-2013. Both tree-ring width and lumen area showed similar year-to-year variability indicating common climatic signals acting on both variables. Tree-ring width increased as previous winter precipitation did. Lumen area responded positively to wet spring conditions, particularly in the case of the juniper. In juniper, cell-wall thickness increased when early summer conditions became drier. These observations are consistent with the presence of intra-annual density fluctuations (IADF) in the juniper latewood which increased in parallel with late-summer water balance. This confirms that latewood IADFs reflect changing water availability in the late growing season as larger tracheid lumens. The analysis of wood anatomical traits allowed inferring long-term growth and wood-anatomical responses to climate at intra-annual scales, which were consistent with previous observations of xylogenesis and the different sensitivity to climate of the two coexisting conifer specie

Wood anatomy as a tool to undesrtand climate and drought influences on growth of coexisting conifers in continental Mediterranean climate

Forecasted warmer and drier conditions will probably lead to reduced growth rates and decreased carbon fixation in long-term woody pools in drought-prone areas. We therefore need a better understanding of how climate stressors such as drought constrain wood formation and drive changes in wood anatomy. Drying trends could lead to reduced growth if they are more intense in spring, when radial growth rates of conifers in continental Mediterranean climates peak. Since tree species from the aforementioned areas have to endure dry summers and also cold winters, we chose two coexisting species: Aleppo pine (Pinus halepensis Mill., Pinaceae) and Spanish juniper (Juniperus thurifera L., Cupressaceae) (10 randomly selected trees per species), to analyze how growth (tree-ring width) and wood-anatomical traits (lumen transversal area, cell-wall thickness, presence of intra-annual density fluctuations\u2014IADFs\u2014in the latewood) responded to climatic variables (minimum and maximum temperatures, precipitation, soil moisture deficit) calculated for different time intervals. Tree-ring width and mean lumen area showed similar year-to-year variability, which indicates that they encoded similar climatic signals. Wet and cool late-winter to early-spring conditions increased lumen area expansion, particularly in pine. In juniper, cell-wall thickness increased when early summer conditions became drier and the frequency of latewood IADFs increased in parallel with late-summer to early-autumn wet conditions. Thus, latewood IADFs of the juniper capture increased water availability during the late growing season, which is reflected in larger tracheid lumens. Soil water availability was one of the main drivers of wood formation and radial growth for the two species. These analyses allow long-term (several decades) growth and wood-anatomical responses to climate to be inferred at intra-annual scales, which agree with the growing patterns already described by xylogenesis approaches for the same species. A plastic bimodal growth behavior, driven by dry summer conditions, is coherent with the presented wood-anatomical data. The different wood-anatomical responses to drought stress are observed as IADFs with contrasting characteristics and responses to climate. These different responses suggest distinct capacities to access soil water between the two conifer species

Modificaci\uf3n de olfat\uf3metros de cuatro brazos para experimentaci\uf3n en broca del caf\ue9, hypothenemus hampei Ferrari (coleoptera: curculionidae)

Modification of four-arm olfactometers to be used with the coffee borer Hypothenemus hampei Ferrari (Coleoptera: Curculionidae). The coffee berry borer, Hypothenemus hampei is considered to be a major pest in coffee producing countries worldwide. As in many insects, the behavior of the coffee borer is modified through aromatic signals. This has triggered important research within the different approaches of olfactometry. Two new innovative designs of olfactometers were evaluated to be used on H. hampei for this research. The olfactometers were built of glass and differ in the angular distribution of their arms and in the insect\u2019s inlet and adaptation zone. A mixture of methanol-ethanol 3:1, with proven attraction properties, was used to evaluate the functionality of these olfactometers. The bioassays were performed using only adult females of H. hampei. On the 90\uba olfactometer, 45% of the insects were strongly attracted to the arm comprised of the alcohol mixture. In the case of the 30\uba olfactometer the positive behavior response was only of 1.5%. During the assays it was observed that the different insect insertion strategies into the olfactometers and the adaptation area had a major influence on results. During the second stage of this research, the 90\uba olfactometer was evaluated through a comparison of the average attraction of each of its 4 arms; there were no significant differences (p<=0.05) in attraction response of H. hampei between arms of the device. It is concluded that the 90\uba olfactometer design is suitable to develop volatile-compound attraction assays on adult females of H. hampei

Disentangling the climate-driven bimodal growth pattern in coastal and continental Mediterranean pine stands.

Mediterranean climate promotes two distinct growth peaks separated by summer quiescence in trees. This bimodal pattern has been associated to favourable growing conditions during spring and autumn when mild temperatures and soil-water availability enhance cambial activity. Climatic models predict progressive warming and drying for the Mediterranean Basin, which could shorten or shift the spring and autumn growing seasons. We explored this idea by comparing two sites with different Mediterranean climate types (continental/dry and coastal/wet) and studied how climate drives the bimodal growth pattern in Aleppo pine (Pinus halepensis). Specifically we investigated the intra-annual changes in wood anatomy and the corresponding formation of density fluctuations (IADF). Trees on both sites were analyzed by dendrometer monitoring and by developing chronologies of wood anatomical traits. Radial-increment dynamics followed a similar bimodal pattern in both sites but coastal trees showed higher increments during the spring and autumn growth peaks, especially in autumn. The summer rest of cambium activity occurs almost one month earlier in the coastal than in the inland site. Lumen area and cell-wall thickness were significantly smaller in the continental site, while the increment rate of cell-wall thickness during an IADF event was much higher in the coastal pines. The accumulated soil moisture deficit was the main climatic constraint of tracheid enlargement in continental pines. Intra-annual density fluctuations were more frequent in the coastal trees where wood anatomy features recover to average values after such events, meanwhile inland trees presented a much lower recovery rate. Growth bimodality and the formation of density fluctuations were linked, but mild climate of the coastal site allows a longer growing season, which explains why trees in this area showed higher and more variable growth rates