Spatial pattern and disease severity of charcoal canker in Hyrcanian forests, north of Iran

Abstract

This research investigated the population density of infected trees with charcoal canker disease and the interaction across the severity of the disease on Quercus castaneifolia in Hyrcanian forests, north of Iran. We used two-dimensional spatial analysis tools with data gathered in point-centred quarter format in 2013. We investigated the co-occurrence of the severity of the disease symptoms using the paired quadrat covariance analysis. The results showed that nearly 54% of the oak trees were affected by the disease so that the dead trees and high disease severity were strongly clustered at broader scales (800 m), the trees with only limited exudates and signs of the activity of Biscogniauxia mediterranea (De Not.) Kuntze occurred in the clusters away from the dead trees. The crown mortality and beetle-infested trees co-occurred with mortality and were strongly correlated. Also, the findings of this research showed that the density of trees per hectare was one of the influential factors on the damage severity of the charcoal canker disease, so that reducing the density could increase the damage severity of the disease.