APA-maps are calculated from tree inventory data of forest stands. Tree coordinates, the competitive ability of trees and information about plot borders are used as inputs to derive APA-maps using multiplicatively weighted Voronoi diagrams. Functions to calculate important characteristics from APA-maps are provided (e.g., size of APA-patches of individual trees and tree species, neighborhood diversity).
The core function of the APAtree-package is the apa_list function that creates APA-maps from tree inventory data and stores it together with the input data and APA-properties in an object of class apa_list.
For a more detailed description of the package see the vignette (vignette("APAtree-vignette", package = "APAtree"))
Additionally, the scripts to produce some of the Figures in Glatthorn (accepted) can be found in the folder paste0(path.package("APAtree"), "/glatthorn_2021").
Glatthorn, Jonas (accepted). A spatially explicit index for tree species or trait diversity at neighborhood and stand level. Ecological Indicators.
Gspaltl, M., Sterba, H., & O'hara, K. L. (2012). The relationship between available area efficiency and area exploitation index in an even-aged coast redwood (Sequoia sempervirens) stand. Forestry, 85(5), 567-577.
R<U+00F6>misch,K. (1995) Durchmesserwachstum und ebene Bestandesstruktur am Beispiel der Kiefernversuchsfl<U+00E4>che Markersbach. In Deutscher Verband forstl. Forschungsanstalten, Sektion Biometrie und Informatik. Gottfried Hempel (ed.) Tagung Tharanth/Grillenburg, Vol. 8, pp. 84<U+2013>103.