CONICET | Buscador de Institutos y Recursos Humanos

Several mid‐sized urban areas have established boundaries overlapping with the distribution of Austrocedrus chilensis (D.Don) Pic.Serm. & Bizzarri forests in Patagonia. These forests suffer a disease whose primary cause is the aggressive pathogen Phytophthora austrocedri. This studyanalyzes the factors related to Austrocedrus disease in an urban and peri‐urban environment,showing that anthropogenic factors related to Phytophthora dispersion predominantly influence thedisease distribution. The study was developed in urban and suburban areas of San Carlos deBariloche county (Río Negro Province, Argentina). A database of requests to fell A. chilensis trees,from the Forest Department of Río Negro Province, was cleaned up and improved through satelliteimages analysis and field sampling. Data were analyzed in order to set up a layer of Austrocedrusdisease presence. From this layer, and from anthropogenic and environmental layers (distance tohouses, distance to roads, precipitation, slope, aspect, altitude, distance to water courses), a riskmodel was developed using the Maximum Entropy (MaxEnt) algorithm. In turn, data from the fieldsampling were assessed by contingency tables and chi square analysis. The results show that disease occurrence in San Carlos de Bariloche county is associated with the insertion of the urban network over areas of native forests. Distance to houses, distance to roads and distance to gardens with irrigation were the most important variables associated with the disease occurrence. A risk model was generated for the study area, which shows the current risk situation for the disease.Urbanization?s advance over the forest modifies key variables related to Phytophthora dispersion,such as the distance from cypress trees to houses and roads, thus progressively increasing the areaat risk of becoming diseased. Based on these results, plausible measures and actions are proposed.