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Drylands represent the main earth biome, providing ecosytemic services to a large number of people. Along these environments, woodlands are often dominated by multi-stemmed trees, which are exploited by local inhabitants to obtain forest products for their livelihood. In central-west Argentina, Neltuma flexuosa (algarrobo) woodlands are distributed across different landform units, varying in topographical and soil characteristics. This research aimed to reconstruct stem-growth time until harvestable diameter was achieved, and biological rotation age according to topo-edaphic variability in three algarrobo forests using dendrochronological methods. Results indicated that landform heterogeneity modulated species radial growth, influencing stem increments and cutting cycle period. In this sense, a decreasing trend in tree productivity emerged along a loamy-to-sandy textured soil gradient. These findings provide useful novel information for N. flexuosa forest management, suggesting the need to account for spatial landform/soil heterogeneity when examining desert forest dynamics. [ABSTRACT FROM AUTHOR]

Climate projections for the Mediterranean area forecast drier and hotter conditions and increasing trend in extreme climatic events such as drought. Scientific evidences reported that extreme dry spells affected the stem growth of different Mediterranean low-elevational pine forests inducing a decrease in tree resilience, defined as the capacity to resist to environmental stress and to recover pre-disturbance functioning. Despite its ecological and economic importance, thus far no study examined Pinus pinea L. (stone pine) resilience to drought events. This research reconstructed stone pine resilience by considering resistance, recovery, and the proportion of trees showing high values of both indexes of several planted stands to three consecutive spring-summer droughts occurred during the second half of the 20th century. Local climatic conditions during dry spells modulated the species resistance and recovery. In this sense, wetter conditions promoted recovery, whereas warmer spring-summer affected stone pine resistance. Moreover, spring rather than summer droughts influenced stone pine resistance and recovery, confirming the species sensitivity to climatic conditions at the beginning of the growing season. Results indicated that while recovery did not significantly changed, the species resistance diminished along the analyzed period. Furthermore, more than 60% of the examined trees were not able to reach pre-drought growth, suggesting a moderate resilience of P. pinea to adverse climatic conditions. The results contribute to improve our understanding of stone pine growth dynamics in the climate-change context of increasing aridity actually occurring in the Mediterranean area, providing useful information for the sustainable management of these natural resources. [ABSTRACT FROM AUTHOR]

Ecotones, as for example riparian zones, have long interested ecologists, due to their potential role in generating species biodiversity and evolutionary novelty, as well as their sensitivity to environmental changes. Along riparian areas, vegetation is recognized for its ecological importance in several ecosystemic processes. In the Central Monte Desert (central-west Argentina), Prosopis flexuosa grows in territories characterized by a permanent access to water reservoirs, e.g. along riverbanks, where the species forms the classic gallery forests. Despite the ecosystemic role of the different Prosopis species distributed in arid lands, thus far no analysis has been conducted regarding the relation between their radial growth and hydrological changes, namely streamflow variability, in riparian settings. To fill this gap of knowledge, we performed a dendrochronological analysis considering several riparian P. flexuosa trees differing in their spatial position in relation to the riverbank. Pointer years, correlation function, and regression analyses show differences in the dendrohydrological signal of the studied species, probably function of tree distance from the river. In this sense, radial growth of trees distributed near the riverbank is tightly coupled to spring-summer (September to March) stream-flow variability, whereas for farthest trees the ring development is driven by a combination of winter and spring river discharge and late-summer precipitation amount. The presented results demonstrate the potentiality of P. flexuosa, and in a broader sense of the Prosopis genus, in dendrohydrological studies. [ABSTRACT FROM AUTHOR]