Climate driven trends in tree biomass increment show asynchronous dependence on tree-ring width and wood density variation

Tree growth is a key ecosystem function supporting climate change mitigation strategies. However climate change may induce feedbacks on radial growth and wood density, affecting the carbon sequestration capacity of forests. Using a mixed modeling technique long-term trends in radial growth, wood density and above-ground biomass, defined as the product of the annual basal area growth with the wood density, of common beech (Fagus sylvatica) and sessile oak (Quercus petraea) in the Belgian Ardennes, were determined and explained using climate drivers of change. This modeling strategy allowed us to determine if the same conclusions can be drawn when only BAI is considered, as is assumed in most carbon sequestration studies, when looking at long-term trends in carbon sequestration. The models indicate that above-ground biomass increment changes over time are more driven by changes in radial growth than by changes in wood density. Nevertheless, the assumption of constant wood density in most carbon sequestration studies is incorrect. Ignoring wood density results in an underestimation of long-term trends in above-ground biomass increment for beech, and an overestimation of above-ground biomass increment for oak. Interesting is that radial growth is mostly driven by climate variables of the current year, whereas wood density is more driven by the climate variables of the previous year. Beech radial growth and wood density is found to be negatively influenced by drought and positively by water availability. Oak radial growth and wood density is negatively affected by late frost and positively by water availability. The findings of this study suggest that radial growth in combination with wood density should be used in carbon sequestration studies as different climate driven long-term trends in radial growth and wood density are found

Herramientas de simulación para el apoyo de toma de decisiones en la gestión forestal adaptativa en Europa

In forest management there is a tendency towards measuring less and simulating more. In this context the development of reliable, user friendly forest simulators has become economically relevant. The objective of this perspective paper is to highlight the recent trends in forest simulation and to identify the remaining challenges to make forest simulation a reliable tool for forest policy and management. Experiences with forest simulators for various purposes in different geographical contexts illustrate how the important challenges of forest decision support can be addressed through flexible customization for different end-user categories, offering spatially explicit approaches at the landscape scale, and integrating empirical and mechanistic models in hybrid and bayesian simulation approaches. Recent development trends in forest simulation for decision support are mainly related to the ever increasing calculation speed and capacity of computers, facilitating the development of robust tools with comfortable user interface and realistic functions and options. Another trend is the combination of simulation tools with optimization and choice algorithms fading away the difference between simulators and decision support systems. The remaining challenges are basically in the high expectations of stakeholders concerning the ability of simulators to predict a range of outcomes in terms of ecosystem services and sustainability indicators, as well as the quality of their outcome in terms of output credibility to stakeholders. Need for accepted and realistic model validation and verification methods preferably using empirical data is crucial in this matter.En la planificación de la gestión forestal existe la tendencia a medir menos y similar más. En este contexto, el desarrollo de simuladores forestales es económicamente relevante para el gestor. El objetivo de este artículo es el de discutir y enfatizar tendencias en el ámbito de la simulación forestal e identificar retos importantes para que la simulación forestal sea una herramienta fiable en el proceso decisorio de la planificación forestal y en el de desarrollo de políticas. Varios ejemplos de simuladores forestales existentes y que responden a objetivos y escalas geográficas distintas, ilustran como la capacidad analítica de los gestores puede mejorar sustancialmente para responder a los grandes retos en el proceso decisorio de la gestión forestal. El artículo presenta simuladores que responden a necesidades de diferentes usuarios y hacen frente a distintas cuestiones, utilizando distintos enfoques y herramientas; desde simuladores espacialmente explícitos basados en modelos empíricos que son integrados con herramientas de optimización, hasta simuladores mecanísticos o basados en enfoques híbridos y bayesianos. El desarrollo más reciente en simulación forestal esta sobretodo relacionado con el incremento de capacidad de cálculo de los computadores, lo que ha facilitado el desarrollo de herramienta robustas y visuales, fáciles de utilizar por los usuarios finales. Otra tendencia, importante es la combinación de herramientas de simulación con técnicas de optimización númerica, lo cual posibilita el desarrollo de los mas modernos sistemas de soporte a la decisión. Uno de los retos más importantes es el de colmar las altas expectativas de los principales agentes y centros decisores forestales en relación a la capacidad de los simuladores y sistemas de apoyo a la decisión para proporcionar información relevante en relación a los servicios ecosistémicos e indicadores de sostenibilidad. En este contexto, es necesaria la validación de los diferentes modelos que configuran los simuladores haciendo uso de información empírica disponible

Clinical added value of MRI to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO):study protocol for an international multicentre prospective diagnostic accuracy study

Abstract Background Abdominal computed tomography (CT) is the standard imaging method for patients with suspected colorectal liver metastases (CRLM) in the diagnostic workup for surgery or thermal ablation. Diffusion-weighted and gadoxetic-acid-enhanced magnetic resonance imaging (MRI) of the liver is increasingly used to improve the detection rate and characterization of liver lesions. MRI is superior in detection and characterization of CRLM as compared to CT. However, it is unknown how MRI actually impacts patient management. The primary aim of the CAMINO study is to evaluate whether MRI has sufficient clinical added value to be routinely added to CT in the staging of CRLM. The secondary objective is to identify subgroups who benefit the most from additional MRI. Methods In this international multicentre prospective incremental diagnostic accuracy study, 298 patients with primary or recurrent CRLM scheduled for curative liver resection or thermal ablation based on CT staging will be enrolled from 17 centres across the Netherlands, Belgium, Norway, and Italy. All study participants will undergo CT and diffusion-weighted and gadoxetic-acid enhanced MRI prior to local therapy. The local multidisciplinary team will provide two local therapy plans: first, based on CT-staging and second, based on both CT and MRI. The primary outcome measure is the proportion of clinically significant CRLM (CS-CRLM) detected by MRI not visible on CT. CS-CRLM are defined as liver lesions leading to a change in local therapeutical management. If MRI detects new CRLM in segments which would have been resected in the original operative plan, these are not considered CS-CRLM. It is hypothesized that MRI will lead to the detection of CS-CRLM in ≥10% of patients which is considered the minimal clinically important difference. Furthermore, a prediction model will be developed using multivariable logistic regression modelling to evaluate the predictive value of patient, tumor and procedural variables on finding CS-CRLM on MRI. Discussion The CAMINO study will clarify the clinical added value of MRI to CT in patients with CRLM scheduled for local therapy. This study will provide the evidence required for the implementation of additional MRI in the routine work-up of patients with primary and recurrent CRLM for local therapy. Trial registration The CAMINO study was registered in the Netherlands National Trial Register under number NL8039 on September 20th 2019

Maintaining Integrity Under Stress:Envelope Stress Response Regulation of Pathogenesis in Gram-Negative Bacteria

The Gram-negative bacterial envelope is an essential interface between the intracellular and harsh extracellular environment. Envelope stress responses (ESRs) are crucial to the maintenance of this barrier and function to detect and respond to perturbations in the envelope, caused by environmental stresses. Pathogenic bacteria are exposed to an array of challenging and stressful conditions during their lifecycle and, in particular, during infection of a host. As such, maintenance of envelope homeostasis is essential to their ability to successfully cause infection. This review will discuss our current understanding of the σE- and Cpx-regulated ESRs, with a specific focus on their role in the virulence of a number of model pathogens