Context

This horizon-scanning project uses phylogenetic approaches to address two research questions:

• Which non-native tree species proposed for future planting in the UK are likely to be the most susceptible to native pests and pathogens?
• Which non-native pests and pathogens pose the greatest future threat to Sitka spruce, a key non-native tree species already widely planted in the UK?

Research aims and objectives

Aims

Assess 1) the likely susceptibility of non-native tree species to native pests and pathogens in the UK, and 2) the likely susceptibility of Sitka spruce to non-native pests and pathogens that might reach the UK in the future.

Objectives

Susceptibility of non-native trees to native pests and pathogens 

• Compile a list of candidate non-native tree species for future planting in the UK, based on databases and expert knowledge.
• Analyse phylogenetic distance between non-native tree species and UK native plants from published large-scale molecular analyses.
• Review the literature to collect data on organisms associated with the closest relatives of non-native trees, which are potentially harmful to tree health.
• Rank the candidate non-native tree species according to likely risk, based on their phylogenetic distance from native tree hosts of potentially harmful organisms.

Susceptibility of Sitka spruce to non-native pests and pathogens

• Compile a list of potential pests and pathogens of Sitka spruce based on databases and expert knowledge.
  Analyse phylogenetic distances between Sitka spruce and known hosts using a published time-calibrated phylogenetic tree for gymnosperms.
• Generate a phylogenetically informed ranking of pest/pathogen species on the basis of the minimum phylogenetic distance between a known host of that species and Sitka spruce, with those with the most closely related host species considered to pose the greatest risk.