An accumulation of climatic stress events has led to years of reduced growth for sugar maple in southern Quebec, Canada

Understanding the influence of climatic variation on forest dynamics is of great ecological and economic interest, and is essential to prescribe silvicultural interventions that will facilitate ecosystem acclimation to global change. However, the retrospective identification of climatic events responsible for the inter-annual variation of tree growth is challenging, notably because both their duration and their subsequent effects can be highly variable in time. In this study, we aimed to (1) quantify empirically the effect of climatic stress events on the short- and long-term growth dynamics of sugar maple trees; (2) compare the effects of different types of climatic events, that is, drought and thaw–freeze; and (3) compare the effects of climatic stress events to those of traditional monthly level climate metrics. To achieve this, we paired cross-dated tree-ring series to monthly and daily-level climate metrics over more than 50 yr in two distinct regions of southern Quebec. While the analysis from monthly level metrics first suggested a weak and non-stationary relationship between climatic conditions and tree growth, the analysis from daily-level metrics showed that climatic stress events, and more particularly thaw–freeze events, were strongly related to the growth of sugar maple trees. Our results suggest that the synergic influence of cumulative climatic stress events, which was exacerbated by insect outbreaks during the early 1980s, induced an important shift in the growth dynamics of sugar maple and in its response to variation in climatic conditions. These results highlight the potential negative impact of global climate change on our capacity to predict stand productivity accurately, especially if climate-sensitive growth models are based on projections of future monthly metrics. Because adverse climatic events are expected to increase both in frequency and in severity over the next decades, a general decrease in the growth rate of sugar maple is apprehended in southern Quebec

Deer browsing and soil disturbance induce cascading effects on plant communities : a multilevel path analysis

Understanding how large herbivores shape plant diversity patterns is an important challenge in community ecology, especially because many ungulate populations in the northern hemisphere have recently expanded. Because species within plant communities can exhibit strong interactions (e.g., competition, facilitation), selective foraging by large herbivores is likely not only to affect the abundance of palatable species, but also to induce cascading effects across entire plant communities. To investigate these possibilities, we first tested the effects of deer browsing and soil disturbance on herbaceous plant diversity patterns in boreal forest, using standard analyses of variance. Second, we evaluated direct and indirect effects of deer browsing and soil disturbance on the small-scale richness of herbaceous taxa using a multilevel path analysis approach. The first set of analyses showed that deer browsing and soil disturbance influenced herb richness. Path analyses revealed that deer browsing and soil disturbance influenced richness via complex chains of interactions, involving dominant (i.e., the most abundant) browsing-tolerant (DBT) taxa and white birch (Betula papyrifera), a species highly preferred by white-tailed deer (Odocoileus virginianus). We found no evidence that an increase of white birch in fenced quadrats was the direct cause of a decrease in herb richness. However, we found strong evidence that a higher abundance of DBT taxa (i.e., graminoids and Circium arvense), both in fenced and unfenced quadrats, increased herb layer richness. We propose an empirical model in which competitive interactions between white birch and DBT taxa regulate the strength of facilitative relationships between the abundance of DBT taxa and herb richness. In this model, deer browsing and the intensity of soil disturbance initiate a complex chain of cascading effects in boreal plant communities by controlling the abundance of white birch

Management of forest regeneration in boreal and temperate deer-forest systems : challenges, guidelines and research gaps

Heavy browsing pressure from large ungulates is a multicontinent phenomenon that causes regeneration failure of many palatable tree species and induces important socioeconomic and ecological impacts in forest ecosystems. The development of forest management practices that address adequately this issue, however, remains scarce and challenging because (1) large herbivores are both a resource and a source of disturbance; (2) the management of forests and ungulate populations remains largely disconnected in practice; and (3) we still lack a good understanding of the role of critical factors, especially deer densities, vegetation attributes, and their interactions, on the magnitude of browsing damages on forest regeneration. We bring new insights into these challenging issues by critically reviewing the current methods used by managers and conservationists to mitigate deer impacts on forest regeneration, emphasizing the spatial scale at which these methods are undertaken. Specifically, we review management actions at multiple scales on both deer populations (e.g., hunting) and vegetation (e.g., silvicultural treatments) that are common to most deer–forest systems and, for that reason, deserve priority investigation. We identify strengths and limitations of current management actions and highlight the main research gaps. Based on this review, we propose a new integrated management scheme that explicitly addresses: (1) the integration and prioritization of management actions, (2) the development of adaptive management plans, and (3) the participation of stakeholders. Conflicting demands by different stakeholders have challenged the effectiveness of management strategies in deer–forest systems. To reverse this situation, we advocate for a shift of paradigm and the development of integrated strategies that (1) bridge the gap between management actions and the design of in situ experiments and (2) coordinate actions at multiple spatial scales on both deer populations and forests. We propose a new framework informed by key objectives and grounded in the adaptive management paradigm to support this transition, and suggest a research agenda for the next decade(s)

High-quality draft genome sequence of pseudomonas wadenswilerensis CCOS 864T

Pseudomonas wadenswilerensis CCOS 864T was isolated in 2014 from forest soil. The organism belongs taxonomically to the Pseudomonas putida group, members of which have been well studied for their potential in biotechnological applications. We present here the draft genome sequence of P. wadenswilerensis CCOS 864T

Comparative genomic analysis of the biotechnological potential of the novel species Pseudomonas wadenswilerensis CCOS 864T and Pseudomonas reidholzensis CCOS 865T

In recent years, the use of whole-cell biocatalysts and biocatalytic enzymes in biotechnological applications originating from the genus Pseudomonas has greatly increased. In 2014, two new species within the Pseudomonas putida group were isolated from Swiss forest soil. In this study, the high quality draft genome sequences of Pseudomonas wadenswilerensis CCOS 864T and Pseudomonas reidholzensis CCOS 865T were used in a comparative genomics approach to identify genomic features that either di ered between these two new species or to selected members of the P. putida group. The genomes of P. wadenswilerensis CCOS 864T and P. reidholzensis CCOS 865T were found to share genomic features for the degradation of aromatic compounds or the synthesis of secondary metabolites. In particular, genes encoding for biocatalytic relevant enzymes belonging to the class of oxidoreductases, proteases and isomerases were found, that could yield potential applications in biotechnology. Ecologically relevant features revealed that both species are probably playing an important role in the degradation of soil organic material, the accumulation of phosphate and biocontrol against plant pathogens

High-quality draft genome sequence of Pseudomonas reidholzensis strain CCOS 865T

We have sequenced and assembled the genome of Pseudomonas reidholzensis CCOS 865T, which was isolated in 2014 from forest soil. Members of the genus Pseudomonas play important roles in environmental systems and are utilized in many biotechnological processes. The genome of this species may provide an important resource for the discovery of novel enzyme activities

Wood properties of black spruce (Picea mariana (Mill.) BSP) in relation to ring width and tree height in even- and uneven-aged boreal stands

Key Message : Wood properties were generally similar in unmanaged even-aged and uneven-aged black spruce stands. In contrast, in managed forests, wood density was higher in even-aged than in uneven-aged stands. As ring width is the discriminant factor, forest management should regulate the intensity of partial cutting to maintain a high wood density. Context : North American boreal forests experience recurrent disturbances, such as fire and insect outbreaks, that shape the structure of even-aged and uneven-aged stands. Ecosystem-based forest management practices, such as partial cutting, aim to increase timber yields, and these forest harvesting approaches are being applied more frequently. Although the influence of these practices on tree growth is well known, few studies have examined their impact on anatomy and density of the resulting wood. Aim : This research studied the relationships between wood properties and ring width and tree heights in even- and uneven-aged black spruce (Picea mariana (Mill.) BSP) stands and how these relationships are modified following partial cutting. Method : Wood density (ring, earlywood, latewood, and maximum density) and anatomical traits (lumen area, cell-wall thickness, and tracheid length) were measured at breast height on the stem of black spruce trees. The measured wood properties were then correlated with ring width and stem height. Results : The model demonstrated significant correlations between most measured wood parameters and ring width with only small differences between even- and uneven-aged unmanaged stands. Five wood properties were influenced by tree height in even-aged and uneven-aged unmanaged plots. Partial cutting increased the number of significant relationships between wood properties (ring, latewood, maximum density, early- and latewood lumen area, tracheid length) and tree height. We detected differences in wood properties between even- and uneven-aged plots. Although we detected no change in average ring density, the variation of intra-annual density increased, due to changes in earlywood and latewood density that resulted in more heterogeneous rings. Conclusion : Partial cutting should take into consideration the age structure of the stand when the density of wood products matter

Complete genome sequence of the cyanogenic phosphate-solubilizing Pseudomonas sp. strain CCOS 191 : a close relative of Pseudomonas mosseli

We sequenced the complete genome of the isolate Pseudomonas sp. CCOS 191. This strain is able to dissolve phosphate minerals and form cyanide. The genome sequence is used to establish the phylogenetic relationship of this species

High-quality draft genome sequence of Streptomyces albidoflavus CCOS 2040, isolated from a Swiss soil sample

Here, we report the high-quality draft genome sequence of the actinomycete Streptomyces albidoflavus CCOS 2040, isolated from a Swiss soil sample. The genome contains 7,136,301 bp with 73.35% GC content. In total, 22 biosynthetic gene clusters, including polyketides and terpenes, were predicted within the sequenced genome