Growth of tree (Pinus sylvestris) and shrub (Amelanchier ovalis) species is constrained by drought with higher shrub sensitivity in dry sites.

We lack understanding of how variable is radial growth of coexisting tree and shrub species, and how growth is constrained by drought depending on site aridity. Here, we compared the radial growth of two widespread and coexisting species, a winter deciduous shrub (Amelanchier ovalis Medik.) and an evergreen conifer tree (Pinus sylvestris L.). We sampled four sites in Northeastern Spain subjected to different aridity levels and used dendrochronological methods to quantify growth patterns and responses to climate variables. The growth of the two species varied between regions, being lower in the driest sites. The first-order autocorrelation (growth persistence) was higher in more mesic sites but without clear differences between species. Tree and shrub growth negatively responded to elevated summer temperatures and positively to spring-summer precipitation and wet conditions. However, negative growth responses of the shrub to drought were only observed in the two driest sites in contrast to widespread responses of the tree. Abrupt growth reductions were common in the drier sites, but resilience indices show that the two species rapidly recovered pre-drought growth levels. The lower growth synchrony of the shrub as compared to the tree can be due to the multistemmed architecture, fast growth and low stature of the shrub. Besides, the high dependency of the shrub growth on summer rainfall can explain why drought limitations were only apparent in the two driest sites. In any case, results point out to the dendrochronological potential of shrubs, which is particularly relevant giving its ability to inhabit woodlands and treeless regions under harsh climatic conditions. Nevertheless, further research is required to elucidate the capacity of shrub species to tolerate drought, as well as to understand how shrubs thrive in water- and cold-limited environments.

From the Wild to the Field: Documentation, Propagation, Pilot Cultivation, Fertilization, and Phytochemical Evaluation of the Neglected and Underutilized Amelanchier ovalis Medik. (Rosaceae).

The snowy Mespilus, or serviceberry (Amelanchier ovalis Medik., Rosaceae) represents a neglected and underutilized small fruit tree species with high nutritional value. In this work, we present the results of a long-term study facilitating the sustainable exploitation of A. ovalis as a new germplasm resource from the Greek flora. Ten wild-growing population samples of A. ovalis have been collected from natural habitats in northern Greece. Asexual propagation trials on these materials delivered successful propagation (83.3% rooting) on a selected genotype via leafy cuttings of young, primary, non-lignified soft wood with the application of the rooting hormone. The ex situ cultivation potential of the selected genotype has been evaluated under distinct fertilization regimes in a pilot field trial. Three-year results of this ongoing trial have shown that A. ovalis does not require external nutrient enhancement to be established during its early stages since plant growth rates between conventional fertilization and control plants were similar for the first two years and higher compared to organic fertilization. Conventional fertilization delivered higher fresh fruit production in the third year, with higher fruit number and fruit size compared to organic fertilization and control plants. The phytochemical potential of the cultivated genotype was assessed via the total phenolic content and radical scavenging activity of separate extracts from leaves, twigs, flowers, and young fruits, which revealed that individual plant organs have strong antioxidant activity despite their moderate total phenolic content. The multifaceted approach applied herein has provided novel data that may set the framework for further applied research toward the sustainable agronomic exploitation of Greek A. ovalis as a diversified superfood crop.