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Drought hardening is a nursery technique aimed to enhance early forest plantation establishment under dry conditions, which is a main limiting factors for plantation success. However, the quantitative effectiveness of drought hardening remains unclear. We conducted a meta-analysis to evaluate the influence of different factors in the effectiveness of drought hardening on seedling post-planting survival and growth. Overall, drought hardening did not significantly affect survival or growth, as several factors induced great heterogeneity, but analyses of those factors explained its effectiveness, especially on survival. A longer time between hardening and transplanting strongly reduced survival. Indoor-grown seedlings did not benefit more from hardening than outdoor-grown seedlings. Evaluations of drought hardening effectiveness in pots showed positive effects on survival but negative effects on growth, while no effects were found in large bed experiments. In field experiments, hardening significantly increased survival and growth with site aridity. Survival benefits were independent of species drought tolerance, measured by osmotic potential at the turgor loss point (π tlp), in moderate to high aridity sites. However, in low aridity sites, hardening increased survival in drought-tolerant species but decreased it in drought-intolerant species. Field results showed that hardening benefited shrubs more than trees in angiosperms. In conclusion, drought hardening at the end of nursery cultivation tend to increase post-planting seedling performance particularly in scenarios limiting post-planting root growth such as in arid climates and pot experiments. Our findings highlight the importance of future research on modelling the interaction between these technical features and species water use strategies.. • Drought hardening effectiveness increases with aridity of planting site. • Species drought tolerance drives hardening effectiveness under low aridity. • Hardening effectiveness is higher in pot outplanting trials than in field trials. • The intensity and duration of hardening increases transplanting survival. • Drought hardening benefits shrubs more than perennial herbs and trees. [ABSTRACT FROM AUTHOR]

Micropropagation has the advantage of genetic homogeneity and reduces difficulties related to obtaining pathogen-free plant material. However, some plant species present challenging problems when used for in vitro culture. This research work dealt with the micropropagation of Quercus pubescens Willd. with the aim of enhancing the percentage proliferation and rooting from micro-cuttings. Microcuttings, containing apical or axillary buds, were taken from two year-old branches using a clone of Q. pubescens grown at the Forest Nursery of Sant' Angelo in Vado, Pesaro-Urbino, Marche, Italy. A preliminary screening of the proliferation was performed using increasing concentration of benzylaminopurine (BA) in the culture medium (0.25; 0.5; 0.75; 1 mg/1) in order to select the best hormones to use in the experiment. From the results it was possible to deduce that BA plays a key role in influencing shoot proliferation, leading to the formation ofa callus and to the production of new shoots. Moreover, we observed that, especially higher BA concentrations promoted the production of a larger number of shorter shoots compared to low concentrations, that produced the small number of longer shoots. Furthermore, these trials have shown that, in order to have a large number of seedlings with an optimal shoot length, it is necessary to divide the process of propagation in two phases. The first phase involves a high concentration of BA, with the aim of increasing the number of new micro-cuttings; the second phase, with lower levels of BA, to increase the length of the shoots. With regards to root induction, the hormone selected was indole-butyric acid (IBA). Results showed that micro-cutting exposed for 24h to higher hormone concentration gave the best results for root induction and root length. The study developed an efficient method for the micropropagation of Q. pubescens for the selection of genotypes in in vitro and sterile (e.g., free microorganisms and insects) conditions. It is envisaged that the development of this protocol paves the way for further utilisation of micro-propagated Q. pubescens in new areas of research, such as in vitro mycorrhization. [ABSTRACT FROM AUTHOR]

Forested patches play an important ecological role in urbanized landscapes. Nevertheless, in particular conditions, trees can paradoxically worsen air quality through the emission of Biogenic Volatile Organic Compounds (BVOCs) (i.e., isoprenoids), which participate to the reactions forming O 3 together with anthropogenic VOCs and nitrogen oxides (NO X ). Given the continuous increase in urban population, there is the necessity of providing urban managers with sustainability indices in urban areas related to these subtle pollutants. Our study aims to give an overview of reference cities or typology of urban areas suitable for expanding the research on future BVOC-O 3 dynamics. Such “reference” cities represent a sort of study target in order to better model and forecast the future behaviours of BVOC emissions and O 3 pollution. Contexts have been selected on both a regional and global scale in both warmer and colder environments, considering future climate scenarios and gradients from more natural conditions. Urban Heat Island and Urban Cold Island effects were also discussed as representative models for anticipating the impact of climatic change on urban trees. Finally, other factors, such as UV rays, Secondary Organic Aerosols wind transportation and the surrounding biome were considered as interactive drivers of the change. [ABSTRACT FROM AUTHOR]

Monitoring of tree traits and tree response to the environment can be integrated with sensor technology. High-resolution monitoring requires a frequent data acquisition, that generally results in hourly measurements for the definition of daily processes, then scaled at monthly, seasonal and annual levels, by producing very large databases. The TreeTalker (TT) technology is an example of a tool for forest monitoring that measures hourly and simultaneously tree parameters and environmental variables, by collecting 1032 attributes per tree per day (43 variables, such as sap flow and stem diameter variation measured every hour). Therefore, we present the TreeTalkersCheck R package built to facilitate the remote checking of the functioning of the TreeTalkers devices. This package contains functions to download, process raw data obtained with TreeTalker devices, and produces a report with all the alerts detected and a complete database with preliminary processing of the data. The package was tested on a database obtained by 60 TT installed on 60 trees in three sites in Tuscany (Central Italy). [Display omitted] • TreeTalkers (TT) are useful tools to monitor tree functional traits. • Checking the functionality of TT is challenging, expensive, and time consuming. • We present an R package to remotely monitor TT devices in real time. • Downloading and primary processing of data is performed by the package. • Daily reports of TT sensors status and recorded data are produced by the package. [ABSTRACT FROM AUTHOR]