Out of nowhere the COVID-19 pandemic has turned people’s everyday lives upside down. Public places in urban areas were closed. However, leaving the house for recreational and leisure purposes in nature was still allowed in Germany – even during lockdown in March and April of 2020. As a result, urban forests have gained unprecedented importance – not only for recreational activities, but also for maintaining social contacts and coping with psychological stress. With these diverse requirements, many people have appropriated urban forests in new and changed ways. Using the example of the forests around the southern German city of Freiburg, a team of researchers from the Department of Societal Change at the Forest Research Institute Baden-Württemberg (FVA) carried out a mixed-method study to investigate how these appropriation practices are working and to shed some light on the relevance of forests for city residents in these circumstances. In addition to the statistical analysis of an online questionnaire, ethnographic observation data and Instagram posts were analyzed. This methodological triangulation was carried out in order to purposefully combine the strengths of each method while at the same time reducing the intrinsic biases and blind spots. This resulted in a better understanding of the importance of urban forest during this extraordinary period of time. Our results show that urban forests became critically important during the lockdown. Many visitors appropriated the forest with very different motives and for different purposes. For many visitors, the forest provided the same functions during this extraordinary period that public spaces otherwise do. The forest was not only consumed as a natural space, but also constructed by visitors as a social space. We can illustrate how this social meaning was both negotiated and reproduced. To provide an abstraction of our results, we refer to the theory of spatial appropriation as well as to new approaches in sociology of space that conceptualize space as a network of social relations. These results give rise to broader questions for future research projects, recreational forest research, forest and health, and forest planning.

lastic surgery is often conducted on bilateral organs, which can result in clustering of data. [1][2][3] Clustering is when some observations within a data set are internally related and, therefore, are more similar when compared with other observations in the data set. An example is patients undergoing bilateral breast surgery.The two breasts of one individual are related and, therefore, are expected to be more alike than the breasts of two individuals. Clustered data can be a challenge when reporting and analyzing data, which is illustrated in the following example.A hypothetical study investigates the effect of tumescence on drain output in patients undergoing breast reduction with and without the use of tumescence. First, we assume that the authors include 40 patients undergoing bilateral breast reduction. They have allocated 20 patients to be treated with tumescence and 20 patients with no tumescence. The authors of this hypothetical study can choose to report their outcomes per patient or per breast. If the authors report the outcome per patient (n = 20 in each group), they potentially lose the data that each breast contributes. Conversely, if they report data per breast