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Increasing water stress is emerging as a global phenomenon, and is anticipated to have a marked impact on forest function. The role of tree functional strategies is pivotal in regulating forest fitness and their ability to cope with water stress. However, how the functional strategies found at the tree or species level scale up to characterise forest communities and their variation across regions is not yet well-established. By combining eight water-stress-related functional traits with forest inventory data from the USA and Europe, we investigated the community-level trait coordination and the biogeographic patterns of trait associations for woody plants, and analysed the relationships between the trait associations and climate factors. We find that the trait associations at the community level are consistent with those found at the species level. Traits associated with acquisitive-conservative strategies forms one dimension of variation, while leaf turgor loss point, associated with stomatal water regulation strategy, loads along a second dimension. Surprisingly, spatial patterns of community-level trait association are better explained by temperature than by aridity, suggesting a temperature-driven adaptation. These findings provide a basis to build predictions of forest response under water stress, with particular potential to improve simulations of tree mortality and forest biomass accumulation in a changing climate.Tree functional strategies regulate responses to water stress, but how these strategies scale up to the forest community level is not well known. This study shows coherent spatial variation in community-level trait associations across temperate forests that is linked to temperature. [ABSTRACT FROM AUTHOR]

Although climate change is expected to drive tree species toward colder and wetter regions of their distribution, broadscale empirical evidence is lacking. One possibility is that past and present human activities in forests obscure or alter the effects of climate. Here, using data from more than two million monitored trees from 73 widely distributed species, we quantify changes in tree species density within their climatic niches across Northern Hemisphere forests. We observe a reduction in mean density across species, coupled with a tendency toward increasing tree size. However, the direction and magnitude of changes in density exhibit considerable variability between species, influenced by stand development that results from previous stand-level disturbances. Remarkably, when accounting for stand development, our findings show a significant change in density toward cold and wet climatic conditions for 43% of the species, compared to only 14% of species significantly changing their density toward warm and arid conditions in both early-and late-development stands. The observed changes in climate-driven density showed no clear association with species traits related to drought tolerance, recruitment and dispersal capacity, or resource use, nor with the temperature or aridity affiliation of the species, leaving the underlying mechanism uncertain. Forest conservation policies and associated management strategies might want to consider anticipated long-term species range shifts alongside the integration of contemporary within-distribution density changes. [ABSTRACT FROM AUTHOR]

Systematic inventories of deadwood in Polish forests are carried out as part of two separate activities: the National Forest Inventory (NFI), and periodic inventories of forest stands for the purpose of forest management plans preparation. These activities differ in their objectives, methodology and scope. The NFI has been conducted continuously since 2005, covering the whole country; its third series was completed in 2019. Measurements of deadwood as part of forest management planning have been carried out since 2012; data for 53.3% of the forest districts have been analysed (229 out of 430), covering 3,989,575 ha of forest. Data from both inventories are collected in the Forest Data Bank. A comparison of the results of both inventories for the same areas has shown similarities, but also differences that affect their interpretation and use for other studies. The volume of deadwood in Polish forests is relatively low as compared to guidelines in the literature, but a positive trend has been observed in recent years. [ABSTRACT FROM AUTHOR]

Two decades after the pan-European set of indicators for sustainable forest management was adopted, the European Commission published the New EU Forest Strategy for 2030. We compared the documents on the basis of a content analysis to determine whether they share the same understanding of sustainable forest management. We looked at whether, and to what extent, the existing indicator set is fit for purpose to monitor progress towards the Strategy's objectives, and the delivery of policy commitments. About two thirds of the identified objectives and commitments in the Strategy can be monitored at least partially by the pan-European set of indicators, whereas new indicators or approaches need to be developed for the remaining third. Several of the indicators are not linked to the Strategy, and some of them are only weakly linked to the policy issues addressed in the Strategy. Our comparison shows a few significant differences between the comprehensive vision of sustainable forest management formulated in the indicator set and the scope of the objectives and commitments in the Strategy. In particular, the forest policy concerns reflected in the Strategy address several issues which are not fully covered in the pan-European indicator set. [ABSTRACT FROM AUTHOR]

Previous studies argue that salicylic acid (SA) plays an important role in the plant signal transduction pathway(s) leading to disease resistance. It has been proposed that one of its modes of action is inhibition of catalase and elevation of H2O2 level in the tissue. To verify the role of SA and H2O2 during pathogenesis, transgenic tobacco plants expressing Saccharomyces cerevisiae CTA1 gene coding for peroxisomal catalase were constructed. These plants possess 2-4-fold higher total catalase activity under normal growth conditions. No symptoms of chlorosis and/or necrosis were observed. Levels of pathogenesis-related proteins (PR) and their respective mRNAs were significantly reduced in the infected leaves of the transgenic plants. No change in PR expression was detected in uninfected leaves of both CTA1 and control plants challenged with TMV. These results suggest that elevation in catalase activity and resulting reduction of H2O2 level results in more severe local disease symptoms, apparently due to alteration of the hypersensitive response mechanism and does not influence systemic acquired resistance after viral infection. [ABSTRACT FROM AUTHOR]