Reaction to release treatments and distinctive attributes of butternut that promote resistance to the canker caused byOphiognomonia clavigignenti-juglandacearum

Abstract

This research examines the impact of light and tree attributes of butternuts, including bark phenotype, on their health. Some butternuts were released by thinning the crowns of neighbouring trees in two locations in Québec, while others were not. Various butternut characteristics related to their health that had been collected by a partner in the Montérégie region are also analysed. The release treatment did not have any significant impact on any health variables. However, their location, the diameter increments before releasing trees and twig collection on some butternuts had a significant impact on some of these variables. For the butternuts of the Montérégie region, their position in the canopy had a significant impact on main stem damage and on the putative resistance to the canker caused by Ophiognomonia clavigignenti-juglandacearum; trees from the upper storey were healthier. Dieback of dark and deep furrowed bark phenotype butternuts was significantly lower than that of the light, shallow furrowed bark ones. Butternuts with a greater annual increase in basal area had better vigour. This was greater in the upper canopy and among the deep furrowed bark butternuts.