Mixed effects of landscape complexity and stand factors on cytospora canker of poplar across two different field soil conditions

ObjectiveThis paper explores the influence mechanism of landscape complexity and stand factors on cytospora canker of poplar caused by Cytospora chrysosperma across two different field soil conditions, to provide theoretical basis for rational allocation of landscape patterns to control cytospora canker effectively, and to further develop sustainable poplar (Populus spp.) plantations.

MethodWe spent 2 years (2018−2019) collecting cytospora canker data across two different soil physical and chemical properties in Xinjiang Uygur Autonomous Region of wester China: one in Karamay City and another in Manasi County. Using general linear mixed effect models (GLMMs) with the random effect of year to analyze how the landscape complexity and stand factors influence cytospora canker at landscape scale.

ResultResults showed that the cytospora canker of Populus nigra and P. alba var. pyramidalis both had significantly positive relationships with tree density, as well as the Shannon diversity index of pests. Compared with P. alba var. pyramidalis, P. nigra had a significant relationship with the height of first live branch. The cytospora canker of the two tree species was both correlated negatively with the proportion of non-poplar hosts, as well as elevation. The cytospora canker had a significant correlation with physical and chemical properties of soil, in the same landscape structure, the disease incidence in Karamay City was higher than that in Manasi County. Under the same soil conditions, the incidence of cytospora canker in simple landscape was higher than that in complex landscape.

ConclusionOverall, our study shows that the occurrence of cytospora canker on poplar can be reduced via management of habitats and enhanced tree resistance at landscape scale, and provides valuable contributions to landscape research and for managing outbreaks of insects and pathogens. In afforestation planning, the potential impact of the surrounding landscape structure on insects and pathogens should be considered. The effects of landscape features on cytospora canker of poplar can be monitored on a large scale and over long periods of time using land cover data to improve economic and environmental benefits.