Earth's forests face grave challenges in the Anthropocene, including hotter droughts increasingly associated with widespread forest die-off events. But despite the vital importance of forests to global ecosystem services, their fates in a warming world remain highly uncertain. Lacking is quantitative determination of commonality in climate anomalies associated with pulses of tree mortality-from published, field-documented mortality events-required for understanding the role of extreme climate events in overall global tree die-off patterns. Here we established a geo-referenced global database documenting climate-induced mortality events spanning all tree-supporting biomes and continents, from 154 peer-reviewed studies since 1970. The analysis quantifies a global "hotter-drought fingerprint" from these tree-mortality sites-effectively a hotter and drier climate signal for tree mortality-across 675 locations encompassing 1,303 plots. Frequency of these observed mortality-year climate conditions strongly increases nonlinearly under projected warming.

Resource use by consumers across patches is often proportional to the quantity or quality of the resource within these patches. In folivores, such proportional use of resources is likely to be more efficient when plants are spatially proximate, such as trees forming a forest canopy. However, resources provided by forest-trees are often not used proportionally. We hypothesised that proportional use of resources is reduced when host trees are isolated among phylogenetically distant neighbours that mask olfactory and visual search cues, and reduce folivore movement between trees. Such phylogenetically distant neighbourhoods might sort out species that are specialists, poor dispersers, or have poor access to information about leaf quality. We studied individual oaks, their leaf size and quality, their folivory and abundance of folivores (mostly Lepidopteran ectophages, gallers and miners), and parasitism of folivores. We found that leaf consumption by ectophages hardly increased with increasing leaf size when host trees were phylogenetically isolated. We found a similar effect on host use by parasitoids in 1 year. In contrast, we found no consistent effects in other folivore guilds. Relative abundances of specialists and species with wingless females declined with phylogenetic isolation. However, resource use within each of these groups was inconsistently affected by phylogenetic isolation. We suggest that phylogenetic isolation prevents ectophages from effectively choosing trees with abundant resources, and also sorts out species likely to recruit in situ on their host tree. Trees in phylogenetically distant neighbourhoods may be selected for larger leaves and greater reliance on induced defences.

Large-scale forest development simulations are invaluable tools that harness mathematical models, computer algorithms, and extensive datasets to forecast the evolution of forest ecosystems across extended periods of time. Their applications span a diverse spectrum, ranging from informing forest policies and projecting the supply of wood and other ecosystem services (such as biodiversity and recreation) to facilitating sustainable forest management strategies. However, these sophisticated tools can often appear as enigmatic 'black boxes' to those not intimately familiar with them. In this presentation, I will illuminate the inner workings of these simulations, shedding light on their foundational assumptions and models. We will also explore the synergies between forest simulations and various domains within forestry research, demonstrating how simulations can significantly amplify the impact of research across these domains.

Forest biodiversity underpins ecosystem functioning and the provision of multiple ecosystem goods and services that are essential to human well-being. Still, the social value of biodiversity is rarely considered in the management of forest resources, potentially compromising ecosystem functioning and social welfare in the future. Moreover, climate change and other sources of uncertainty add further complexity to the implementation of biodiversity-oriented forest management. These multiple uncertainties are expected to affect the interactions among forest taxa and the relationships between forests and the socio-economic context in which they are embedded. Consequently, uncertainty needs to be addressed in the decision-making process and conservation planning, seeking for robust alternatives that safeguard forest biodiversity regardless of future states of the world. Here we discuss approaches to tackle these issues, analyzing economic aspects of biodiversity-oriented management, with a focus on retention forestry, and the socially optimal biodiversity supply in temperate forests under multiple sources of uncertainty.