Valuable new help for woodland managers to understand birch die-back, a phenomenon that affects many new native woodland planting schemes in Scotland, is contained in a new Information Note from the Forestry Commission.
The note is entitled Birch Dieback in Scotland. It was written by Sarah Green from the Tree Health Division of Forest Research, with support from the Scottish Forestry Trust, and is based on three years of research at native woodland planting sites around Scotland.

  Birch dieback typically begins between five and 10 years after planting, and affected trees show a steady deterioration in crown health. The research confirmed pathogenic fungi as the main causal agents, in particular Anisogramma virgultorum and Marssonina betulae, and indicated that genetic variability within birch species could influence disease expression. Researchers looked at a range of factors that might contribute to trees' susceptibility to fungal pathogens, including soil type and quality, exposure, provenance and origin.
 
  The Note says further studies are needed on the inoculum source, life cycle and infection biology of the fungi before it is possible to make management recommendations for reducing the establishment and spread of the disease. Meanwhile, an investigation has begun into the role of birch provenance and phenotype in determining susceptibility to A. virgultorum and M. betulae to try to identify less disease-susceptible stock for use in future planting schemes in Scotland after researchers noted that on some sites, pockets of naturally regenerated trees were healthy despite the presence of the disease elsewhere on the site