The present dataset was collected as part of WP1 (forest biodiversity and mental health and well-being), as well as WP2 (forest biodiversity and subjective microclimate) in three peri-urban forests in vicinity of the cities of Leipzig (Germany), Vienna (Austria) and Ottignies-Louvain-la-Neuve (Belgium) in September 2021. It encompasses environmental (site, forest biodiversity condition, species ID / species composition) as well as subjective questionnaire measures (attention, mental health, mental well-being, subjective thermal comfort, stress, perceived restorative potential, nature relatedness, personality, perceived restorative potential of soundscapes, perceptions of bio-, geo- and anthrophony, single items on perceived naturalness, perceived biodiversity, forest density, light conditions, colourfulness, forest floor vegetation, preference / pleasantness of the environment, as well as demographic data). Forest biodiversity was operationalized using tree diversity levels in the visual scencery of participants, resulting in a low (monoculture), medium (2-species-mix) and high (4-5 species mix) diversity condition. We strived for diversifying included tree species among sites for investigating species identity and composition effects on response measures. Forest patches were further selected according to a dilution design where feasible (with the tree species serving as the monoculture being present in the medium and high tree diversity condition and the second tree species of the medium tree diversity condition being likewise present in the high diversity condition). We included a total of 223 participants whom were randomly assigned to either one of three tree diversity conditions or an urban control. Each partipant spent 20 minutes in the respective forest patch / the urban control with the instruction to focus on what could be seen and heard. Before and after the intervention questionnaires were completed.

A total of 223 participants were randomly assigned to one of three (visual) tree diversity conditions (low: monoculture / medium: 2-species mix / high: 4-5 species-mix) or an urban control resulting in 56 participants each for the low / high tree diversity and urban control condition opposed to 55 participants in the medium tree diversity condition. We recruited 70 participants in Leipzig (17 participants in the medium / high tree diversity condition opposed to 18 participants for the low tree diversity / urban control condition), 66 participants in Vienna (15 participants in the low tree diversity condition, and 17 in the medium / high tree diversity condition and the urban control) and 87 participants in Ottignies-Louvain-la-Neuve (21 participants in the medium tree diversity condition and the urban control, 22 participants in the high tree diversity condition and 23 participants in the low tree diversity condition).

Leipziger Auwald, Leipzig (Germany); Wienerwald, Vienna (Austria);

data was collected in Leipzig on the 3rd & 4th September , in Vienna on the 10th & 11th September and in Ottignies-Louvain-la-Neuve on the 24th & 25th September 2021.

Weather conditions were comparable for Leipzig and LLN with one warm, sunny and one cloudy rather cool day. In Vienna, weather was sunny and hot / warm on both days.

We aim to quantify the effects of forest biodiversity on mental health and well-being, under consideration of attention restoration and stress recovery as potential mediators. Balancing out the need for ecological, as well as psychological significance of forest biodiversity, data analyses comprise both objective as well as subjective forest biodiversity measures.We hypothesize that it is perceived rather than actual forest biodiversity that positively influences mental health and well-being by restoring attentional capacities and facilitating stress recovery. Data will be analyzed using multiple group SEM to account for potential differences between peri-urban forests (Leipziger Auwald / Wienerwald / Bois de Lauzelle).