Modeling the effect of stand and site characteristics on the probability of mistletoe infestation in Scots pine stands using remote sensing data

Over the past decade, the presence of mistletoe (Viscum album ssp. austriacum) in Scots pine stands has increased in many European countries. Understanding the factors that influence the occurrence of mistletoe in stands is key to making appropriate forest management decisions to limit damage and prevent the spread of mistletoe in the future. Therefore, the main objective of this study was to determine the probability of mistletoe occurrence in Scots pine stands in relation to stand-related endogenous factors such as age, top height, and stand density, as well as topographic and edaphic factors. We used unmanned aerial vehicle (UAV) imagery from 2,247 stands to detect mistletoe in Scots pine stands, while majority stand and site characteristics were calculated from airborne laser scanning (ALS) data. Information on stand age and site type from the State Forest database were also used. We found that mistletoe infestation in Scots pine stands is influenced by stand and site characteristics. We documented that the densest, tallest, and oldest stands were more susceptible to mistletoe infestation. Site type and specific microsite conditions associated with topography were also important factors driving mistletoe occurrence. In addition, climatic water balance was a significant factor in increasing the probability of mistletoe occurrence, which is important in the context of predicted temperature increases associated with climate change. Our results are important for better understanding patterns of mistletoe infestation and ecosystem functioning under climate change. In an era of climate change and technological development, the use of remote sensing methods to determine the risk of mistletoe infestation can be a very useful tool for managing forest ecosystems to maintain forest sustainability and prevent forest disturbance.