Knowledge about the stand structure and dynamics of subalpine forests is crucial to preserve their multifunctionality. In the present study, we reconstructed the spatiotemporal dynamics of a subalpine Pinus cembra forest in the eastern Italian Alps in response to natural disturbances and forest management. We adopted a concurrent point pattern, dendroecological and growth dominance (GD) analysis. We mapped and measured all trees of Pinus cembra and Larix decidua in a 1 ha plot. We analyzed intra- and interspecific spatial patterns and spatial autocorrelation of tree size and age. We explored establishment dynamics and shifts in competition by analyzing growth suppression/release patterns and GD trends. Results showed a clumped, uneven-aged, multilayered structure where pine was dominant. The synergic action of ecological and human-induced factors is discussed to explain the prevalence of pine over time. Spatial pattern and autocorrelation analyses suggest a different colonization strategy of the two species, in which pine established after small-scale perturbations and experienced a stronger inter- and intra-specific competition. The interruption of tree establishment and shift in GD toward large trees resulting from the lack of forest management are the most important findings of this research. This highlights the importance of an active management to avoid the homogenization of the forest structure that is generally associated with a reduction in biodiversity and protective ability of forests.

The need to understand the carbon sequestration ability of trees under current and future climatic scenarios is fundamental to predict the role of forest in counterbalancing the global warming. In this study, we investigated the carbon sequestration ability of Pinus sylvestris L. in a setting of pure and mixed forests with Quercus petraea (Matt.) Liebl. in Central Poland. Beside the traditional growth measures, i.e., Ring Width, Basal Area Increment, and wood density, we utilized also a new Index called BAIden, which combines Basal Area Increment and mean ring wood density to depict the carbon sequestration ability of trees. Pinus sylvestris showed different sensitivity to climatic variability depending on tree admixture, while the Basal Area Increment and wood density presented few differences between pure and mixed forests. According to the BAIden index, carbon accumulation in P. sylvestris showed similar sensitivity to climatic variability in pure and mixed forests. The new index was also informative on the main climatic drivers of carbon sequestration. Considering future climatic scenarios, the carbon sequestration ability of P. sylvestris will be facilitated by rising temperatures in late winter-early spring and reduced by decreasing precipitation and rising temperatures during summer. Finally, we discussed the perspective and applicability of BAIden for further studies on carbon sequestration ability under climate change.

Increasing atmospheric CO₂ concentration and nitrogen deposition are, among the global change related drivers, those playing a major role on forests carbon sequestration potential, affecting both their productivity and water-use efficiency. Up to now, results are however contrasting, showing that the processes underlying them are far from being fully comprehended. In this study, we adopted an innovative approach to simulate the increase of N deposition in a sessile oak forest in North-Eastern Italy, by fertilizing both from above and below the canopy. We observed the dynamics of basal area increment, intrinsic water-use efficiency and of several leaf functional traits over 4 years, to evaluate how the added nitrogen and the two different fertilization system could affect them. We were not able, however, to detect any shift, besides a common yearly variability related to a prevailing background environmental forcing. To this end, we considered as relevant factors both the short time-span of the observation and the relatively low rate of applied nitrogen. Therefore, we stress the importance of long-term, manipulative experiments to improve the understanding of the C sequestration and mitigation ability of forests in response to increased N deposition.

International timber trading is subject to rigorous certification schemes that require the disclosure of essential information, including the tree species and geographic origin of the timber in question. Regrettably, the lack of readily accessible forensic tools to verify compliance has facilitated the proliferation of illegal timber trading, with dramatic consequences for ecosystems and biodiversity. The objective of this study was to investigate the potential of a multichemical approach based on the multielement and strontium isotope ( ⁸⁷ Sr/ ⁸⁶ Sr) ratio analysis combined with chemometrics to test sample recognition according to their species and geographic origin. The sampling area covered a portion of the Eastern Alpine region, which is characterised by a significant economic reliance on wood. The study focused on three representative species from local forests: Norway spruce, European larch, and Swiss stone pine. Samples were characterised from stands grown on diverse bedrock types. Our findings revealed a strikingly consistent variation in the multielement profiles across different species, thereby enabling flawless sample recognition. Considering the geographic origin, the ⁸⁷ Sr/ ⁸⁶ Sr ratio proved to be a pivotal parameter, by virtue of its correlation with the geo-lithological composition of the growing area. Combining the chemical markers, an accurate sample classification based on multiple decision trees was attained, even comparing forest stands grown on the same bedrock type. These findings offer novel insights into the utilisation of chemical markers in provenancing and authenticity studies, thereby enhancing the adoption of integrated approaches to counteract illegal timber trade.

Whole wood can be used as a practical alternative to α-cellulose in tree-ring 13C isotopic (δ13C) analysis. However, the consistency of the relationships between δ13C of whole wood (δ13CW) and α-cellulose (δ13CC) and their climatic sensitivity can vary across contrasting forest stand structures in tree species composition and along an eco-climatic gradient. We assessed whether δ13CW captures inter-annual variation and climatic sensitivity that are comparable to those obtained from δ13CC of Pinus sylvestris L. The study was conducted across three monospecific and two mixed-species forest stands spanning Mediterranean, temperate and continental-temperate climates. Using 145 individual tree rings from 15 trees, we analyzed offset and correlation between δ13CW and δ13CC, centered around two site-specific pointer drought years (1983 and 2014), including the 2 years before and after drought. Bootstrapped correlation and linear mixed-effect models were used to evaluate and compare the climatic signal strength between δ13CW and δ13CC across the study sites and among monospecific and mixed-species forest stands. Across sites and stand species composition types, δ13CW and δ13CC exhibited significantly different δ13C values, with a constant offset of 1.3‰ (±0.13‰ standard deviation). δ13C values were strongly correlated (91–98%) for the two substrates, showing comparable inter-annual variation and similar sensitivity to climatic factors. We conclude that δ13CW appears to be a reliable alternative to δ13CC under our eco-climatic and forest structural conditions. Our results confirm previously reported strong correlations and stable offset between δ13CW and δ13CC in P. sylvestris. By demonstrating this consistency across contrasting stand composition and wide climatic gradients, our study adds empirical support for the use of δ13CW when cellulose extraction is not feasible. δ13CW is a faster, less labor-intensive and more cost-effective alternative method to quantify, based on pointer years, the effects of water stress on tree growth in large-scale spatial dendro-isotopic studies at the level of annual resolution.