Data for: How Should We Measure the DBH of Multi-Stemmed Urban Trees?
Description
This dataset contains intensive measurements, as well as locational data, on 569 street trees in Philadelphia, PA, USA, taken in the summer of 2017, in the course of field research for the article “How Should We Measure the DBH of Multi-Stemmed Urban Trees?” Some base data (e.g., year and season of planting, cultivar) is from the Pennsylvania Horticultural Society's planting records of 2003-2015, from which the Target trees were drawn (cf. article for methodology). The .xlsx file has two worksheets: the data itself, and an extensive metadata tab that explains each column’s contents. The trees themselves are from three genera (Malus, Prunus, and Zelkova); some trees’ cultivar is known (and noted in the dataset); others are unknown, and noted as such. The measurements include mm-accuracy stem diameters taken at a variety of heights (with all heights recorded to the nearest cm), total height and crown width in two directions, as well as a number of environmental and cultivation-linked variables (crown light exposure, vigor, soil dimensions and competing trees, pruning impacts, etc.). This dataset could be used to further explore some of the questions about crown architecture raised by previous researchers. Such questions include urban street tree crown eccentricities (McPherson et al., 2016), environmental characteristics associated with multi-stemmed trees (Bellingham and Sparrow, 2009; Dunphy et al., 2000; Stokes et al., 2011), crown width/DBH relationships (Hemery, 2005), and basal area relationships above and below forking (Matérn, 1990; Minamino and Tateno, 2014; Murray, 1927). Because we also gathered data for each tree pertaining to vigor, crown light exposure, available soil area, and other characteristics, other researchers could use our dataset to examine the roles that such characteristics play in tree sizing and crown architecture. One key question for researchers is which characteristics of allometry transfer from rural to urban forests—and which need amendment or replacement for urban application (McHale et al. 2009).