Biomass functions for the two alien tree species Prunus serotina Ehrh. and Robinia pseudoacacia L. in floodplain forests of Northern Italy

As one cause for biodiversity loss, invasive alien species are a worldwide threat. In forests, however, invasive tree species can also have an enormous biomass potential which can be harvested while taking measures against the species. Allometric equations help estimating the biomass but are often only available for the native range of the species. This lack on information complicates the management of invaded stands, and the equations presented here should help fill this gap. The above-ground biomass for single trees of black cherry (Prunus serotina Ehrh.) and black locust (Robinia pseudoacacia L.) in Ticino/Italy was estimated with differing explanatory variables as total, stem, crown, and leaf biomass. Regression equations of P. serotina were compared with equations from North America. The methods to derive biomass estimates from fresh weight and volumetric measurements in combination with wood densities were critically examined. The biomass could be estimated well by using "diameter" as explanatory variable. The productivity of P. serotina was lower here compared to its range of origin. Biomass estimates from volumetric measurements combined with the truncated cone formula have lead to systematic overestimations. Also the use of volumetric measurements combined with wood density measurements has overestimated comparable estimates from fresh weight measurements. peerReviewe

Exploring the Potential of Mobile Laser Scanning to Quantify Forest Structural Complexity

Today, creating or maintaining forest structural complexity is a management paradigm in many countries due to the positive relationships between structural complexity and several forest functions and services. In this study, we tested whether the box-dimension (Db), a holistic and objective measure to describe the structural complexity of trees or forests, can be used to quantify the structural complexity of 14 European beech (Fagus sylvatica L.) dominated forest plots by means of mobile laser scanning (MLS). The goal of this study was to explore the potential of this approach for quantifying the effect of leaves (summer vs winter) and management (lately unmanaged vs managed) on forest structural complexity. The findings suggest that repeated measurements on the same site and at the same time yielded consistent results if the measuring scheme is standardized. The results also showed that standardized measurement protocols allowed quantifying differences in forest structural complexity due to season. The highest stand structural complexity was found in leaf-on condition during summer, with the complexity being significantly higher than in winter condition. Also, in case of our beech-dominated plots, managed forests were more complex in structure than formerly managed but now unmanaged forests. This study illustrates the potential of MLS for monitoring the changes in forest structural complexity and allows correcting stand structural information for seasonality

Stability of food proteins at high pressure conditions

High pressure (HP) is particularly suited to study protein folding/unfolding, revealing subtle structural rearrangements not accessible by other types of denaturation. HP also has many industrial-scale advantages over heat treatments, including “greener” processing and preservation of nutritional values, colors, and flavors of foods. We have combined in situ HP with small-angle (X-ray and neutron) scattering (SAS) and spectrophotometry to follow the structure in solution of proteins of interest for the food industry. SAS is an essential technique for obtaining structural, but low-resolution, information about proteins, when conventional high-resolution structural biology methods are not possible. I will illustrate this approach with two studies on proteins of food interest: (i) bovine β-lactoglobulin (BLG), a whey protein with a high propensity to bind to various bioactive molecules. We probed by SANS1 and absorbance the effects on pressure stability and reversibility of BLG of the binding of retinol (vitamin A), resveratrol (polyphenol), and biliverdin (linear tetrapyrrole chromophore) to different sites on the protein2, 3. (ii) C-phycocyanin (CPC), a phycobiliprotein from cyanobacteria, to which tetrapyrrole chromophores are covalently attached and which can be used as a natural blue dye in the food industry. We studied by SAXS and absorbance HP-induced CPC unfolding and reversibility from two oligomeric states of the protein as a function of pH. Acknowledgements LLB, SOLEIL, and I2BC facilities are acknowledged for beamtime and proteomic expertise. This work was also supported by ANSO Project No. ANSOCR-PP-2021- 01. References 1. Annighöfer B, et al. High pressure cell to investigate protein unfolding up to 600 MPa by small-angle neutron scattering. Rev Sci Instr 2019;90:025106. 2. Minic S, et al. Effect of ligands on HP-induced unfolding and oligomerization of β-lactoglobulin. Biophysical J 2020;119:2262-74. 3. Minic S, et al. Structure of proteins under pressure: covalent binding effects of biliverdin on beta-lactoglobulin. Biophysical J 2022;121:2514-25

Advanced Aboveground Spatial Analysis as Proxy for the Competitive Environment Affecting Sapling Development

Tree saplings are exposed to a competitive growth environment in which resources are limited and the ability to adapt determines general vitality and specific growth performance. In this study we analyzed the aboveground spatial neighborhood of oak [Quercus petraea (Matt.) Liebl.] and beech (Fagus sylvatica L.) saplings growing in Germany, by using hemispherical photography and terrestrial laser scanning as proxy for the competitive pressure saplings were exposed to. The hemispherical images were used to analyze the light availability and the three-dimensional (3D) point clouds from the laser scanning were used to assess the space and forest structure around the saplings. The aim was to increase the precision with which the biomass allocation, growth, and morphology of the saplings could be predicted by including more detailed information of their environment. The predictive strength of the models was especially increased through direct neighborhood variables (e.g., relative space filling), next to the light availability being the most important predictor variable. The biomass allocation patterns within the more light demanding oak were strongly driven by the space availability around the saplings. Diameter and height growth variables of both species reacted significantly to changes in light availability, and partly also to the neighborhood variables. The leaf morphology [as leaf-area ratio (LAR)] was also driven by light availability and decreased with increasing light availability. However, the branch morphology (as mean branch weight) could not be explained for oak and the model outcome for beech was hard to interpret. The results could show that individuals of the same species perform differently under constant light conditions but differing neighborhoods. Assessing the neighborhood of trees with highly precise measurement devices, like terrestrial laser scanners, proved to be useful. However, the primary response to a dense neighborhood seemed to be coping with a reduction of the lateral light availability aboveground, rather than responding to an increase of competition belowground. The results suggest continuing efforts to increase the precision with which plant environments can be described through innovative and efficient methods, like terrestrial laser scanning

Insights into the relationship between hydraulic safety, hydraulic efficiency and tree structural complexity from terrestrial laser scanning and fractal analysis

The potential of trees to adapt to drier and hotter climates will determine the future state of forests in the wake of a changing climate. Attributes connected to the hydraulic network are likely to determine a tree’s ability to endure drought. However, how a tree’s architectural attributes related to drought tolerance remains understudied. To fill this gap, we compared the structural complexity of 71 trees of 18 species obtained from terrestrial laser scanning (TLS) with key hydraulic thresholds. We used three measures of xylem safety, i.e., the water potential at 12%, 50%, and 88% loss of hydraulic conductance (P12, P50, P88) and specific hydraulic conductivity (Ks) to assess the trees’ drought tolerance. TLS data were used to generate 3D attributes of each tree and to construct quantitative structure models (QSMs) to characterize the branching patterns. Fractal analysis (box-dimension approach) was used to evaluate the overall structural complexity of the trees (Db) by integrating horizontal and vertical extent as well as internal branching patterns. Our findings revealed a significant relationship between the structural complexity (Db) and the three measures of xylem safety along with Ks. Tree species with low structural complexity developed embolism-resistant xylem at the cost of hydraulic efficiency. Our findings also revealed that the Db had a stronger and more significant relationship with branch hydraulic safety and efficiency compared to other structural attributes examined. We conclude that Db seems to be a robust descriptor of tree architecture that relates to important branch hydraulic properties of a tree

Three-dimensional quantification of tree architecture from mobile laser scanning and geometry analysis

The structure and dynamics of a forest are defined by the architecture and growth patterns of its individual trees. In turn, tree architecture and growth result from the interplay between the genetic building plans and environmental factors. We set out to investigate whether (1) latitudinal adaptations of the crown shape occur due to characteristic solar elevation angles at a species’ origin, (2) architectural differences in trees are related to seed dispersal strategies, and (3) tree architecture relates to tree growth performance. We used mobile laser scanning (MLS) to scan 473 trees and generated three-dimensional data of each tree. Tree architectural complexity was then characterized by fractal analysis using the box-dimension approach along with a topological measure of the top heaviness of a tree. The tree species studied originated from various latitudinal ranges, but were grown in the same environmental settings in the arboretum. We found that trees originating from higher latitudes had significantly less top-heavy geometries than those from lower latitudes. Therefore, to a certain degree, the crown shape of tree species seems to be determined by their original habitat. We also found that tree species with wind-dispersed seeds had a higher structural complexity than those with animal-dispersed seeds (p < 0.001). Furthermore, tree architectural complexity was positively related to the growth performance of the trees (p < 0.001). We conclude that the use of 3D data from MLS in combination with geometrical analysis, including fractal analysis, is a promising tool to investigate tree architecture

Combined hydrogels of starch and β-lactoglobulin as matrices for the preservation of C-phycocyanin

The color of food products is an important aspect in food industry, and its preservation remains a big challenge. We aim to preserve the natural blue dye of C-phycocyanin (C-PC) phycobiliprotein from Spirulina microalgae. For this purpose, we incorporated C-PC in combined starch and β-lactoglobulin (BLG) hydrogels by using a high-pressure (HP) process. Indeed, in thermal treatment, the color derived from C-PC is entirely lost. We characterized the obtained HP gels by both rheology and small-angle X-ray scattering (SAXS). Various formulations of binary (BLG/C-PC) and ternary (starch/BLG/C-PC) systems were tested under HP up to 4,500 bar. A good preservation of the C-PC pigment was established by mixing BLG and starch with C-PC at pH 7, with concentrations of 180, 5, and 10 mg/mL, respectively. Identical component concentrations were maintained in the binary systems. Structure of gels was characterized by SAXS providing insight of C-PC interactions with BLG and starch after HP process which leads to the formation of solid gels with larger mesh compared to two-component systems. This results in enhanced mechanical properties, which were determined by amplitude and frequency sweep measurements using a rheometer with applied plane/plane geometry. Therefore, adding starch, even at small concentration, significantly improves gel visual appearance and mechanical properties. Our study reveals that preservation through HP treatment is more effective than high temperature treatment, as visually observed through the sustained color integrity of C-PC blue dye

The use of starch and β-lactoglobulin composite hydrogels as frameworks for preserving c-phycocyanin

Our study aimed to preserve the natural blue dye of C-phycocyanin (C-PC) phycobiliprotein from Spirulina microalgae due to its importance in the food industry. We incorporated C-PC into hydrogels formed by combining starch and β-lactoglobulin (BLG) using high-pressure (HP) processing to achieve this objective. Notably, thermal treatment resulted in the complete loss of colour derived from C-PC. We performed a comprehensive characterization of the resulting HP gels by rheology measurements, texture profile analysis (TPA), small-angle X-ray scattering (SAXS), and scanning electron microscopy (SEM). Different compositions of binary (BLG/C-PC) and ternary (starch/BLG/C-PC) systems were processed under high-pressure (HP) conditions reaching up to 4,500 bar. The C-PC pigment was effectively preserved by mixing BLG and starch with C-PC at pH 7, maintaining concentrations of 180, 5, and 10 mg/mL, respectively. The same concentrations of components were retained in the binary systems. Rheological properties of the gels were determined using a rheometer with plane/plane geometry, and texture analysis was conducted through TPA. These findings enabled the assessment of food gel's properties, such as hardness, springiness, chewiness, and cohesiveness. The structural characteristics of the gels were determined by SAXS, offering insights into the interactions between C-PC, BLG, and starch after HP processing. Adding CPC and starch formed solid gels with a larger mesh than the pure BLG gels. SEM scans of the gel surface revealed that all components influenced the overall morphology of gels. Even at low concentrations, the addition of starch notably influenced the gels' visual appearance and mechanical properties. Our investigation highlights the superior effectiveness of HP treatment in the preservation of C-PC compared to high-temperature treatment, evident in the sustained colour integrity of the C-PC blue dye

Predicting the spatial and temporal dynamics of species interactions in Fagus sylvatica and Pinus sylvestris forests across Europe

The productivity and functioning of mixed-species forests often differs from that of monocultures. However, the magnitude and direction of these differences are difficult to predict because species interactions can be modified by many potentially interacting climatic and edaphic conditions, stand structure and previous management. Process-based forest growth models could potentially be used to disentangle the effects of these factors and thereby improve our understanding of mixed forest functioning while facilitating their design and silvicultural management. However, to date, the predicted mixing effects of forest growth models have not been compared with measured mixing effects. In this study, 26 sites across Europe, each containing a mixture and monocultures of Fagus sylvatica and Pinus sylvestris, were used to calculate mixing effects on growth and yield and compare them with the mixing effects predicted by the forest growth model 3-PGmix. The climate and edaphic conditions, stand structures and ages varied greatly between sites. The model performed well when predicting the stem mass and total mass (and mixing effects on these components), with model efficiency that was usually >0.7. The model efficiency was lower for growth or smaller components such as foliage mass and root mass. The model was also used to predict how mixing effects would change along gradients in precipitation, temperature, potential available soil water, age, thinning intensity and soil fertility. The predicted patterns were consistent with measurements of mixing effects from published studies. The 3-PG model is a widely used management tool for monospecific stands and this study shows that 3-PGmix can be used to examine the dynamics of mixed-species stands and determine how they may need to be managed.This article is based upon work from COST Action EuMIXFOR, supported by COST (European Cooperation in Science and Technology). Funding for the Czech Republic site was provided by the MŠMT projects COST CZ – LD14063 and LD14074. All contributors thank their national funding institutions and the forest owners for agreeing to establish the plots and to measure and analyse data from the plots. The first author was funded by a Heisenberg Fellowship (FO 791/4-1) from the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). Mário Pereira was supported by European Investment Funds by FEDER/COMPETE/POCI– Operacional Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT – Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013 as well as by project Interact-Integrative Research in Environment, Agro-Chain and Technology, NORTE-01-0145-FEDER-000017, research line BEST, co-financed by FEDER/NORTE 2020

The instrument suite of the European Spallation Source

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact o