Drought resistance and resilience of rhizosphere communities in forest soils from the cellular to ecosystem scale - insights from C pulse labeling.

The link between above- and belowground communities is a key uncertainty in drought and rewetting effects on forest carbon (C) cycle. In young beech model ecosystems and mature naturally dry pine forest exposed to 15-yr-long irrigation, we performed C pulse labeling experiments, one during drought and one 2 wk after rewetting, tracing tree assimilates into rhizosphere communities. The C pulses applied in tree crowns reached soil microbial communities of the young and mature forests one and 4 d later, respectively.

Uniform carbon reserve dynamics along the vertical light gradient in mature tree crowns.

Understanding the within-tree variability of non-structural carbohydrates (NSC) is crucial for interpreting point measurements and calculating whole-tree carbon balances. Yet, little is known about how the vertical light gradient within tree crowns influences branch NSC concentrations and dynamics. We measured NSC concentrations, irradiance and key leaf traits in uppermost, sun-exposed and lowest, shaded branches in the crowns of mature, temperate trees from nine species with high temporal resolution throughout one growing season.

Stem growth phenology, not canopy greening, constrains deciduous tree growth.

Canopy phenology is a widely used proxy for deciduous forest growth with various applications in terrestrial ecosystem modeling. Its use relies on common assumptions that canopy greening and stem growth are tightly coordinated processes, enabling predictions on the timing and the quantity of annual tree growth. Here, we present parallel observations of canopy and stem growth phenology and annual stem increment in around 90 deciduous forest trees with diffuse-porous (Fagus sylvatica, Acer pseudoplatanus, Carpinus betulus) or ring-porous (Quercus robur × petraea) wood anatomy.

Do multimodal search cues help or hinder teleoperated search and rescue missions?

In search and rescue missions, teleoperated rovers equipped with sensor technology are deployed into harsh environments to search for targets. To support the search task, unimodal/multimodal cues can be presented via visual, acoustic and/or haptic channels. However, human operators often perform the search task in parallel with the driving task, which can cause interference of attentional resources based on multiple resource theory.

Object affordances from the perspective of an avatar.

Humans often interact with avatars in video gaming, workplace, or health applications, for instance. The present research studied object affordances from an avatar's perspective. In two experiments, participants responded to objects with a left/right keypress, indicating whether the objects were upright or inverted.

Rapid hydraulic collapse as cause of drought-induced mortality in conifers.

Understanding the vulnerability of trees to drought-induced mortality is key to predicting the fate of forests in a future climate with more frequent and intense droughts, although the underlying mechanisms are difficult to study in adult trees. Here, we explored the dynamic changes of water relations and limits of hydraulic function in dying adults of Norway spruce ( L.) during the progression of the record-breaking 2018 Central European drought.

A candidate gene association analysis identifies SNPs potentially involved in drought tolerance in European beech (Fagus sylvatica L.).

Studies of genetic variation underlying traits related to drought tolerance in forest trees are of great importance for understanding their adaptive potential under a climate change scenario. In this study, using a candidate gene approach, associations between SNPs and drought related traits were assessed in saplings of European beech (Fagus sylvatica L.) representing trees growing along steep precipitation gradients.

Effect of Vapor Pressure Deficit on Gas Exchange in Wild-Type and Abscisic Acid-Insensitive Plants.

Stomata control the gas exchange of terrestrial plant leaves, and are therefore essential to plant growth and survival. We investigated gas exchange responses to vapor pressure deficit (VPD) in two gray poplar () lines: wild type and abscisic acid-insensitive () with functionally impaired stomata. Transpiration rate in increased linearly with VPD, up to about 2 kPa.

Know-how or know-why? The role of hybrid electric vehicle drivers' acquisition of eco-driving knowledge for eco-driving success.

Hybrid electric vehicles (HEVs) can contribute to sustainable transport. Yet, their real-world energy efficiency depends on HEV drivers' eco-driving behaviour. Eco-driving knowledge is key for successful eco-driving.

Statistical power in two-level models: A tutorial based on Monte Carlo simulation.

The estimation of power in two-level models used to analyze data that are hierarchically structured is particularly complex because the outcome contains variance at two levels that is regressed on predictors at two levels. Methods for the estimation of power in two-level models have been based on formulas and Monte Carlo simulation. We provide a hands-on tutorial illustrating how a priori and post hoc power analyses for the most frequently used two-level models are conducted.

Resilient Leaf Physiological Response of European Beech ( L.) to Summer Drought and Drought Release.

Drought is a major environmental constraint to trees, causing severe stress and thus adversely affecting their functional integrity. European beech ( L.) is a key species in mesic forests that is commonly expected to suffer in a future climate with more intense and frequent droughts.

Inferring foliar water uptake using stable isotopes of water.

A growing number of studies have described the direct absorption of water into leaves, a phenomenon known as foliar water uptake. The resultant increase in the amount of water in the leaf can be important for plant function. Exposing leaves to isotopically enriched or depleted water sources has become a common method for establishing whether or not a plant is capable of carrying out foliar water uptake.

Effects of drought on leaf carbon source and growth of European beech are modulated by soil type.

Drought potentially affects carbon balance and growth of trees, but little is known to what extent soil plays a role in the trade-off between carbon gain and growth investment. In the present study, we analyzed leaf non-structural carbohydrates (NSC) as an indicator of the balance of photosynthetic carbon gain and carbon use, as well as growth of European beech (Fagus sylvatica L.) saplings, which were grown on two different soil types (calcareous and acidic) in model ecosystems and subjected to a severe summer drought.

The Role of Interaction Patterns with Hybrid Electric Vehicle Eco-Features for Drivers' Eco-Driving Performance.

Objective: The objective of the present research was to understand drivers' interaction patterns with hybrid electric vehicles' (HEV) eco-features (electric propulsion, regenerative braking, neutral mode) and their relationship to fuel efficiency and driver characteristics (technical system knowledge, eco-driving motivation).

Background: Eco-driving (driving behaviors performed to achieve higher fuel efficiency) has the potential to reduce CO emissions caused by road vehicles. Eco-driving in HEVs is particularly challenging due to the systems' dynamic energy flows.

Ectomycorrhizal ecology is imprinted in the genome of the dominant symbiotic fungus Cenococcum geophilum.

The most frequently encountered symbiont on tree roots is the ascomycete Cenococcum geophilum, the only mycorrhizal species within the largest fungal class Dothideomycetes, a class known for devastating plant pathogens. Here we show that the symbiotic genomic idiosyncrasies of ectomycorrhizal basidiomycetes are also present in C. geophilum with symbiosis-induced, taxon-specific genes of unknown function and reduced numbers of plant cell wall-degrading enzymes.

Recovery of trees from drought depends on belowground sink control.

Climate projections predict higher precipitation variability with more frequent dry extremes(1). CO2 assimilation of forests decreases during drought, either by stomatal closure(2) or by direct environmental control of sink tissue activities(3). Ultimately, drought effects on forests depend on the ability of forests to recover, but the mechanisms controlling ecosystem resilience are uncertain(4).

Ecodriving in hybrid electric vehicles--Exploring challenges for user-energy interaction.

Hybrid electric vehicles (HEVs) can help to reduce transport emissions; however, user behaviour has a significant effect on the energy savings actually achieved in everyday usage. The present research aimed to advance understanding of HEV drivers' ecodriving strategies, and the challenges for optimal user-energy interaction. We conducted interviews with 39 HEV drivers who achieved above-average fuel efficiencies.

The influence of the soil on spring and autumn phenology in European beech.

Tree phenology is a key discipline in forest ecology linking seasonal fluctuations of photoperiod and temperature with the annual development of buds, leaves and flowers. Temperature and photoperiod are commonly considered as main determinants of tree phenology while little is known about interactions with soil chemical characteristics. Seedlings of 12 European beech (Fagus sylvatica L.

How tree roots respond to drought.

The ongoing climate change is characterized by increased temperatures and altered precipitation patterns. In addition, there has been an increase in both the frequency and intensity of extreme climatic events such as drought. Episodes of drought induce a series of interconnected effects, all of which have the potential to alter the carbon balance of forest ecosystems profoundly at different scales of plant organization and ecosystem functioning.

Changes in the dynamics of foliar N metabolites in oak saplings by drought and air warming depend on species and soil type.

Climate change poses direct or indirect influences on physiological mechanisms in plants. In particular, long living plants like trees have to cope with the predicted climate changes (i.e.

A phenological timetable of oak growth under experimental drought and air warming.

Climate change is expected to increase temperature and decrease summer precipitation in Central Europe. Little is known about how warming and drought will affect phenological patterns of oaks, which are considered to possess excellent adaptability to these climatic changes. Here, we investigated bud burst and intra-annual shoot growth of Quercus robur, Q.

Concomitant dendrometer and leaf patch pressure probe measurements reveal the effect of microclimate and soil moisture on diurnal stem water and leaf turgor variations in young oak trees.

Tree water relations and their dependence on microclimate and soil moisture were studied over several months in young oaks (Quercus robur L.) subjected in large lysimeter-based open top chambers to environments with a controlled soil water supply. Automated single point dendrometers and the recently developed leaf patch clamp pressure (LPCP) probe were used for monitoring water-related stem radius variations (ΔW) and turgor-dependent leaf patch pressures (Pp).

Provenance-specific growth responses to drought and air warming in three European oak species (Quercus robur, Q. petraea and Q. pubescens).

Provenance-specific growth responses to experimentally applied drought and air warming were studied in saplings of three European oak species: Quercus robur, Quercus petraea and Quercus pubescens. Four provenances of each species were grown in large open-top chambers and subjected to four climates: control, periodic drought, air warming or their combination in 3 subsequent years. Overall growth responses were found among species and provenances, with drought reducing shoot height growth and stem diameter growth and air warming stimulating shoot height growth but reducing stem diameter growth and root length growth.