Trees are an important carbon sink as they accumulate biomass through photosynthesis1. Identifying tree species that grow fast is therefore commonly considered to be essential for effective climate change mitigation through forest planting. Although species characteristics are key information for plantation design and forest management, field studies often fail to detect clear relationships between species functional traits and tree growth2. Here, by consolidating four independent datasets and classifying the acquisitive and conservative species based on their functional trait values, we show that acquisitive tree species, which are supposedly fast-growing species, generally grow slowly in field conditions. This discrepancy between the current paradigm and field observations is explained by the interactions with environmental conditions that influence growth. Acquisitive species require moist mild climates and fertile soils, conditions that are generally not met in the field. By contrast, conservative species, which are supposedly slow-growing species, show generally higher realized growth due to their ability to tolerate unfavourable environmental conditions. In general, conservative tree species grow more steadily than acquisitive tree species in non-tropical forests. We recommend planting acquisitive tree species in areas where they can realize their fast-growing potential. In other regions, where environmental stress is higher, conservative tree species have a larger potential to fix carbon in their biomass.

• MeSH
• biomasa MeSH
• časové faktory MeSH
• druhová specificita MeSH
• fotosyntéza MeSH
• klimatické změny MeSH
• lesy MeSH
• půda chemie   MeSH
• sekvestrace uhlíku MeSH
• stromy * růst a vývoj   klasifikace   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda MeSH

BACKGROUND AND AIMS: Mixed forest plantations are increasingly recognized for their role in mitigating the impacts of climate change and enhancing ecosystem resilience. Yet, there remains a significant gap in understanding the early-stage dynamics of species trait diversity and interspecies interactions, particularly in pure deciduous mixtures. This study aims to explore the timing and mechanisms by which trait diversity of deciduous species and competitive interactions influence yield, carbon allocation and space occupation in mixed forests, both above and below ground. METHODS: A forest inventory was conducted in planted monocultures, two-species and four-species mixtures of European Acer, Tilia, Carpinus and Quercus, representing a spectrum from acquisitive to conservative tree species. Effects of competition were assessed with linear mixed-effects models at the level of biomass and space acquisition, including leaf, canopy, stem and fine root traits. KEY RESULTS: Early above-ground growth effects were observed 6 years post-planting, with significant biomass accumulation after 8 years, strongly influenced by species composition. Mixtures, especially with acquisitive species, exhibited above-ground overyielding, 1.5-1.9 times higher than monocultures. Fine roots showed substantial overyielding in high-diversity stands. Biomass allocation was species specific and varied markedly by tree size and the level of diversity and between acquisitive Acer and the more conservative species. No root segregation was found. CONCLUSIONS: Our findings underscore the crucial role of species trait diversity in enhancing productivity in mixed deciduous forest plantations. Allometric changes highlight the need to differentiate between (active) acclimatizations and (passive) tree size-related changes, but illustrate major consequences of competitive interactions for the functional relationship between leaves, stem and roots. This study points towards the significant contributions of both above- and below-ground components to overall productivity of planted mixed-species forests.

• Klíčová slova
• Acer platanoides, Carpinus betulus, Quercus robur, Tilia cordata, Mixed plantations, biomass allocation, canopy, fine roots, interspecific competition, overyielding, plasticity, tree diversity,
• MeSH
• Acer fyziologie   růst a vývoj   MeSH
• aklimatizace * fyziologie   MeSH
• biomasa * MeSH
• druhová specificita MeSH
• dub (rod) fyziologie   růst a vývoj   MeSH
• kořeny rostlin fyziologie   růst a vývoj   MeSH
• lesy * MeSH
• stromy * fyziologie   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH

Increasing water stress is emerging as a global phenomenon, and is anticipated to have a marked impact on forest function. The role of tree functional strategies is pivotal in regulating forest fitness and their ability to cope with water stress. However, how the functional strategies found at the tree or species level scale up to characterise forest communities and their variation across regions is not yet well-established. By combining eight water-stress-related functional traits with forest inventory data from the USA and Europe, we investigated the community-level trait coordination and the biogeographic patterns of trait associations for woody plants, and analysed the relationships between the trait associations and climate factors. We find that the trait associations at the community level are consistent with those found at the species level. Traits associated with acquisitive-conservative strategies forms one dimension of variation, while leaf turgor loss point, associated with stomatal water regulation strategy, loads along a second dimension. Surprisingly, spatial patterns of community-level trait association are better explained by temperature than by aridity, suggesting a temperature-driven adaptation. These findings provide a basis to build predictions of forest response under water stress, with particular potential to improve simulations of tree mortality and forest biomass accumulation in a changing climate.

• MeSH
• biomasa MeSH
• dehydratace MeSH
• klimatické změny MeSH
• lesy * MeSH
• listy rostlin MeSH
• podnebí MeSH
• stromy * fyziologie   MeSH
• teplota MeSH
• voda metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• Spojené státy americké MeSH
• Názvy látek
• voda MeSH