Tree stem diameter and height of Araucaria araucana, Nothofagus pumilio and Nothofagus dombeyi in mixed stands affected to different levels by anthropogenic disturbance in south-central Chile

Context: Around half of the Araucaria-Nothofagus forests in Chile are affected by anthropogenic disturbances such as logging, grazing, and seed harvesting, causing forest structure to become more heterogeneous. This can critically affect natural regeneration and stand development. It also challenges forest management and yield estimations, involving tree height predictions. The data allow to assess the impact of anthropogenic disturbances on forest structure and to identify optimal tree height models and calibration designs. Based on the data provided, a general workflow for this purpose was developed and published on GitHub as R software (Zhou & Zwanzig 2022). Location: Mixed Araucaria-Nothofagus forests of the Andes Cordillera in the Araucaria Region in south-central Chile. Latitude, longitude and altitude of the plots is provided in the data table. Taxon: Monkey Puzzle tree (Araucaria araucana (Molina) K.Koch), Lenga Beech (Nothofagus pumilio (Poepp. & Endl.) Krasser), Coigue (Nothofagus dombeyi (Mirb.) Oerst.) Methods: A total of twelve stands were studied at four different sites and classified into four different intensities of anthropogenic disturbance depending on the intensity of the combined effects of logging, grazing and seed harvesting. In 25 to 36 plots per stand, horizontal point sampling measurements of stem diameter as well as of height of selected trees were carried out using a basal area factor of 4 m² per hectare. Diameter at breast height (DBH, in cm) was measured for all selected trees and total tree height (HT, in m) was measured for one-third of them using a Haga device. For ten of the plots, in which no trees were found by horizontal point sampling, 'NA' is entered for species and no values are given for DBH and HT in the data table. Funding: The field data collection was funded through the project 016/2019 “Indicadores fenológicos y estructurales de alteración de hábitat en bosques de Araucaria”, being part of the Fondo de Investigación del Bosque Nativo (FIBN) of the Corporación Nacional Forestal (CONAF) and the Ministry of Agriculture of Chile. Contributions: JH, PC and AP conceived the field study and acquired the funds; EK, JH, PC and AP performed the empirical observations; XZ, EK and MZ reviewed and processed the data collection for publication