Tree species of concern in New Brunswick, Canada. I. Current status and threats

Abstract

A process was developed by the New Brunswick Forest Gene Conservation Working Group to identify conservation needs for native tree species in New Brunswick. A multi-stakeholder, consensus-based, expert opinion process was employed to formulate a set of criteria and a rating system, which were then applied to identify tree species in New Brunswick requiring conservation attention at the genetic level. Known or presumed alien invasive insect or fungus species threaten three of these species: butternut (Juglans cinerea), American beech (Fagus grandifolia), and white elm (Ulmus americana). The fourth species, bur oak (Quercus macrocarpa) - with only a few remaining populations in the province - is threatened primarily by land development. Knowledge of the level, type, and pattern of genetic variability differs widely, depending on the species. Only American beech is naturally broadly distributed in the province. The distribution of the other three species is limited by their specific habitat requirements, and contributes to their vulnerability to new threats.