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Purpose of ReviewResilience is a key concept to deal with an uncertain future in forestry. In recent years, it has received increasing attention from both research and practice. However, a common understanding of what resilience means in a forestry context and how to operationalise it is lacking. Here, we conducted a systematic review of the recent forest science literature on resilience in the forestry context, synthesizing how resilience is defined and assessed.Recent FindingsBased on a detailed review of 255 studies, we analysed how the concepts of engineering resilience, ecological resilience and social-ecological resilience are used in forest sciences. A clear majority of the studies applied the concept of engineering resilience, quantifying resilience as the recovery time after a disturbance. The two most used indicators for engineering resilience were basal area increment and vegetation cover, whereas ecological resilience studies frequently focus on vegetation cover and tree density. In contrast, important social-ecological resilience indicators used in the literature are socio-economic diversity and stock of natural resources. In the context of global change, we expected an increase in studies adopting the more holistic social-ecological resilience concept, but this was not the observed trend.SummaryOur analysis points to the nestedness of these three resilience concepts, suggesting that they are complementary rather than contradictory. It also means that the variety of resilience approaches does not need to be an obstacle for operationalisation of the concept. We provide guidance for choosing the most suitable resilience concept and indicators based on the management, disturbance and application context.

In Mediterranean environments, gully erosion is responsible for large soil losses. It has since long been recognized that slopes under vegetation are much more resistant to soil erosion processes compared to bare soils and improve slope stability. Planting or preserving vegetation in areas vulnerable to erosion is therefore considered to be a very effective soil erosion control measure. Re-vegetation strategies for erosion control rely in most cases on the effects of the above-ground biomass in reducing water erosion rates, whereas the role of the below-ground biomass is often neglected or underestimated. While the above-ground biomass can temporally disappear in semi-arid environments, roots may still be present underground and play an important role in protecting the topsoil from being eroded. In order to evaluate the potential of plant species growing in Mediterranean environments to prevent shallow mass movements on gully or terrace walls, the root reinforcement effect of 25 typical Mediterranean matorral species (i.e. shrubs, grasses herbs, small trees) was assessed, using the simple perpendicular model of Wu et al. (Can Geotech J 16:19-33, 1979). As little information is available on Mediterranean plant root characteristics, root distribution data were collected in SE-Spain and root tensile strength tests were conducted in the laboratory. The power root tensile strength-root diameter relationships depend on plant species. The results show that the shrubs Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. have the strongest roots, followed by the grass Brachypodium retusum (Pers.) Beauv. The shrubs Nerium oleander L. and the grass Avenula bromoides (Gouan) H. Scholz have the weakest roots in tension. Root area ratio for the 0-0.1 m topsoil ranges from 0.08% for the grass Piptatherum miliaceum (L.) Coss to 0.8% for the tree Tamarix canariensis Willd. The rush Juncus acutus L. provides the maximum soil reinforcement to the topsoil by its roots (i.e. 304 kPa). Grasses also increase soil shear strength significantly (up to 244 kPa in the 0-0.1 m topsoil for Brachypodium retusum (Pers.) Beauv.). The shrubs Retama sphaerocarpa (L.) Boiss. and Anthyllis cytisoides L. are increasing soil shear strength to a large extent as well (up to 134 and 160 kPa respectively in the 0-0.10 m topsoil). Whereas grasses and the rush Juncus acutus L. increase soil shear strength in the topsoil (0-0.10 m) to a large extent, the shrubs Anthyllis cytisoides (L.), Retama sphaerocarpa (L.) Boiss., Salsola genistoides Juss. Ex Poir. and Atriplex halimus L. strongly reinforce the soil to a greater depth (0-0.5 m). As other studies reported that Wu's model overestimates root cohesion values, reported root cohesion values in this study are maximum values. Nevertheless, the calculated cohesion values are used to rank species according to their potential to reinforce the soil.

Mitochondria are central key players in cell metabolism, and mitochondrial DNA (mtDNA) instability has been linked to metabolic changes that contribute to tumorigenesis and to increased expression of pro-tumorigenic genes. Here, we use melanoma cell lines and metastatic melanoma tumors to evaluate the effect of mtDNA alterations and the expression of the mtDNA packaging factor, TFAM, on energetic metabolism and pro-tumorigenic nuclear gene expression changes. We report a positive correlation between mtDNA copy number, glucose consumption, and ATP production in melanoma cell lines. Gene expression analysis reveals a down-regulation of glycolytic enzymes in cell lines and an up-regulation of amino acid metabolism enzymes in melanoma tumors, suggesting that TFAM may shift melanoma fuel utilization from glycolysis towards amino acid metabolism, especially glutamine. Indeed, proliferation assays reveal that TFAM-down melanoma cell lines display a growth arrest in glutamine-free media, emphasizing that these cells rely more on glutamine metabolism than glycolysis. Finally, our data indicate that TFAM correlates to VEGF expression and may contribute to tumorigenesis by triggering a more invasive gene expression signature. Our findings contribute to the understanding of how TFAM affects melanoma cell metabolism, and they provide new insight into the mechanisms by which TFAM and mtDNA copy number influence melanoma tumorigenesis.

The original version of this article unfortunately contained a mistake. Figs. 4a and 4c were duplicated. This Figure has now been corrected.

Jatropha curcas (jatropha) is an oil crop cultivated in (sub)tropical regions around the world, and holds great promise as a renewable energy source. However, efforts to fully commercialize jatropha are currently hampered by the lack of genetic diversity in the extant breeding germplasm, and by the toxicity of its seeds meaning that its seed cake cannot be used as a protein source in animal feed, among other constraints. In Mexico, the species' native range, there are jatropha plants whose seeds are used to prepare traditional meals. This non-toxic jatropha 'type' is considered to harbour low genetic variation due to a presumed domestication bottleneck and therefore to be of limited breeding value; yet, very little is known regarding its origin and genetic diversity. Using genotyping-by-sequencing (GBS), we extensively genotyped both indigenous toxic and non-toxic jatropha collected along roads and home gardens throughout southern Mexico. Single nucleotide polymorphism diversity in non-toxic jatropha is relatively high, particularly in northern Veracruz state, the probable origin of this germplasm. Genetic differences between toxic and non-toxic indigenous genotypes are overall quite small. A a genome-wide association study supported a genomic region (on LG 8, scaffold NW_012130064), probably involved in the suppression of seed toxicity. Conservation actions are urgently needed to preserve this non-toxic indigenous, relatively wild germplasm, having potential as a fuel feedstock, animal feed and food source among other uses. More generally, this work demonstrates the value of conservation genomic research on the indigenous gene pool of economically important plant species.

Using data from 20 even-aged and homogeneous mature beech and oak study plots in Flanders (Northern Belgium), an analysis of the empirical relationships between the rates of leaf area index (LAI) change throughout the leaf development of 2008 and stand, site and meteorological variables was performed. Species-specific multiple linear regressions were fitted between the rates of LAI change and the predictors for two distinct periods from April until August. After a sharp increase in LAI following budburst, the seasonal LAI development for both species showed a marked period of stationary LAI development over all study plots. The cause for the cessation of LAI growth was assumed to be the decline of air temperature and radiation during this period. Later on, the rate of LAI development restarted similarly in every plot. The influence of weather on LAI development was high and its effects were different between species, with beech mostly affected by radiation and oak negatively related to minimal and maximal values of air temperature. Furthermore, our analysis suggested that stand structural (tree density and stand basal area for both species) and tree growth characteristics (average tree-ring width ratio for oak) variables were major drivers of the LAI development during early spring. Later during the growth period, stand variables became less predominant in affecting LAI development. Site quality variables affected LAI development to a lesser extent. The seasonal LAI development was found very similar among stands. This study adds a more accurate and comprehensive approach to the modelling of LAI development during leaf growth of two important European temperate deciduous forest species.

The number of initiatives aimed at the evaluation of Sustainable Forest Management has risen considerably since the UNCED Conference in Rio de Janeiro in 1992. In a large number of countries and regions standards with Principles, Criteria and Indicators of Sustainable Forest Management (SFM) have been developed. In many cases, this development took place within the framework of an intergovernmental or international initiative. Sometimes the initiative was taken by national or local organisations. Standards were often developed for the purpose of forest certification. In this research, 164 standards for SFM were collected worldwide and compared using multivariate statistics. The comparison was carried out using a reference standard specially designed for this purpose. It is a generic tool that can be used for any comparative study between the contents of standards. Although a number of typical sustainability elements are present in most standards, differences between standards are substantial. The main cause of variation between standards is the difference between levels of application. Standards developed for the National level are less detailed and contain many elements concerning monitoring aspects to be evaluated at sub-national scale. The more detailed standards for assessment at the Forest Management Unit (FMU) level combine monitoring aspects with a large number of management aspects. These different conditions between FMU and National/Sub-National Level and, therefore, the need for level-specific Criteria and Indicators are well known and accepted by the forestry profession. A second and less known cause of variation between standards is the difference in geographical origin. The observed geographical differences between standards can be explained by biophysical and socio-economic differences between countries and regions. Standards from developing countries in the South most often emphasise the social and economic aspects of sustainability, while they give little attention to the need for research-based information. Standards from industrialised countries in the North on the other hand, strongly emphasise the ecological forest functions and the need for research-based information. Harmonisation among standards is only recommended as far as differences are caused by a lack of capacity or by socio-economic inequity. These deficiencies should be eliminated through international cooperation in order to obtain a more harmonised standard of SFM throughout the world.

As the global community intensifies efforts to combat climate change, insights on the influence of management on forest carbon stocks and fluxes are becoming invaluable for establishing sustainable forest management practices. However, accurately and efficiently monitoring carbon stocks remains technologically challenging. In this study, we aim to (1) assess the effect of forest management on carbon stock by comparing unconfounded pairs of managed and unmanaged forests in the National Park Brabantse Wouden (Flanders, Belgium) and (2) leverage the complementary strengths of optical, light detection and ranging (lidar), and synthetic aperture radar (SAR) remote sensing technologies to improve overall accuracy and scalability in carbon stock estimation. Remote sensing data from Sentinel-2, Sentinel-1, and a canopy height product derived from the Global Ecosystem Dynamics Investigation (GEDI) mission and Sentinel-2 were used as predictors in a generalized additive model (GAM) to estimate carbon stock. The combination of Sentinel-1 and Sentinel-2 significantly improved model accuracy (R2=0.73, RMSE=59.21 t ha−1, MAE=50.29 t ha−1) compared to a model using only Sentinel-2 indices (R2=0.56, RMSE=99.44 t ha−1, MAE=91.40 t ha−1). The addition of canopy height estimates did not affect the model fit. While field assessment exhibited higher carbon stocks in unmanaged stands compared to managed ones, this difference was not detectable using a remote sensing model that incorporated Sentinel-2, Sentinel-1, and/or GEDI-derived variables. Potential explanations for this discrepancy include signal saturation and the need for more training data.

Boswellia papyrifera has been an important multipurpose tree species in central and eastern Africa since ancient times. The species is best known for its non-timber forest product, frankincense. In addition, it has numerous environmental, socio-economic, traditional and industrial uses. However, the species is declining at an alarming rate and thus needs priority in conservation. Populations are facing degradation due to agricultural expansion, overgrazing, fire, poor incense harvesting practices, shifting cultivation, termite and other infestations and urgent conservation measures are required to save the species. Conservation strategies could include promotion of natural regeneration through closed areas and enrichment planting. Nevertheless, more ecological and silvicultural studies are required in order to streamline specific interventions.