Tree biodiversity in Bornean lowland forest: What are the key species for forest city development in the new capital city of Indonesia?

PLOS ONE | https://doi.org/10.1371/journal.pone.0320489 April 8, 2025 4 / 19 PLOS ONE Tropical urban tree selection Density (D) is the ratio of the number of individuals to the total area sampled, while frequency (F) is the ratio of the number of quadrats in which a species occurs to the number of quadrats observed. Thus, relative density (RD) is the density of a given species (D) divided by the den- sity of all species (multiplied by 100) and relative frequency (RF) is the frequency of a given species (F) divided by the frequency of all species (multiplied by 100). Relative dominance (Rdom) is the basal area of a given species expressed as a percentage of the total basal area of all species present (maximum value of 100). These three measures, RF, RD, and Rdom, are summed to calculate the Importance Value Index (IVI), which lies between 0 and 300 [34]. The diversity of tree species was calculated as the Shannon-Wiener Index (H’). This diver- sity metric was calculated using R v. 3.6.3 [35] package vegan [36], provided in Eqn. 2. Fig 1. Map of research locations around Ibu Kota Negara Nusantara (Nusantara Capital City), East Kalimantan, Indonesia. https://doi.org/10.1371/journal.pone.0320489.g001