Search

The Amazon faces worsening droughts, yet little is known about large-scale variation in the physiological limits of Amazon trees. Here, the authors reveal family-level conservatism in embolism resistance and estimate that Brazilian and Guiana shield forests are more resistant than Western Amazonia forests.

Plants across many ecosystems are increasingly exposed to dryness stress. Using meta-analysis, the authors show that plants can adjust their hydraulic traits in response to drought and other global change factors, but not equally across traits and not enough to prevent lethal hydraulic failure.

Tree longevity is thought to increase in harsh environments, but global evidence of drivers is lacking. Here, the authors find two different pathways for tree longevity: slow growth in resource limited environments and increasing tree stature and/or slow growth in competitive environments.

Drought is a growing issue in tropical rainforests. Here, the authors revisit a long-term rainfall manipulation experiment in the Amazon to show that tree mortality was followed by community-level adjustments to reduced precipitation.

The long-held assumption that the storage of starch and related compounds helps plants cope with drought stress is now supported by much needed experimental evidence.

Analysis of data from forest plants worldwide shows that margins between threshold xylem pressures at which plants suffer damage and the lowest xylem pressures experienced are small, with no difference between dry and wet forests, providing insight into why drought-induced forest decline is occurring in both arid and wet forests.

Forest carbon source and sink processes may have contrasting climatic sensitivities. This analysis on 177 coniferous forest sites shows that carbon fluxes and wood formation are coupled but not fully synchronous at intra-annual scales, with peaks in cambial activity preceding those in photosynthesis and respiration.

A simple conceptual model helps to answer the question of which forests are more likely to die following droughts.

Canopy nitrification contributes up to 80% of the nitrate reaching the soils via throughfall in European forests, according to analyses of nitrogen deposition and oxygen isotopes in nitrate at ten forested sites.

Combining global-scale data on species’ edaphoclimatic niches, phylogeny and hydraulic traits for >44,000 woody plant species, the authors map areas of hydraulic risk and show that local assemblages at greater hydraulic risk have a higher probability of drought-induced mortality.

Forest dynamics are monitored at large scales with remote sensing, but individual tree data are necessary for ground-truthing and mechanistic insights. This study on high temporal resolution dendrometer data across Europe reveals that the 2018 heatwave affected tree physiology and growth in unexpected way.

The role of non-structural carbohydrates (NSC) in mediating the impacts of drought in tropical trees is unclear. Here, the authors analyse leaf and branch NSC in 82 Amazon tree species across a Basin-wide precipitation gradient, finding that allocation of leaf NSC to soluble sugars is higher in drier sites and is coupled to tree hydraulic status.

A pan-Amazon study of forests shows large variations in drought tolerance traits and finds that forests in regions of pronounced climate change are losing biomass and may be operating beyond their hydraulic limits.

Although plant functional trait combinations reflect ecological trade-offs at the species level, little is known about how this translates to whole communities. Here, the authors show that global trait composition is captured by two main dimensions that are only weakly related to macro-environmental drivers.

The mechanisms underlying drought-induced tree mortality are not fully resolved. Here, the authors show that, across multiple tree species, loss of xylem conductivity above 60% is associated with mortality, while carbon starvation is not universal.

Enhanced drought frequency and magnitude have impacted tree mortality, leading to multiple examples of regional-scale dieback. This Review outlines the mechanisms leading to mortality, including carbon starvation and hydraulic failure.

The profound, overwhelming effects of human activities on the carbon balance of temperate and boreal forests are demonstrated. Apart from the direct effects of forest management, they show that carbon sequestration by this important component of the biosphere is driven by the imbalance in the global nitrogen cycle determined by human activities.

Phyllosphere microbiota of beech and Scots pine at European continental scale is influenced by the host species and associated foliar traits, as well as by temperature and nitrogen deposition, according to 16S rRNA gene sequencing analyses on leaf epiphytic microbes.