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Forest Research home > Research > Protecting trees > Reducing the impact of non-native or invasive vertebrates to forestry > Management of non-native or invasive vertebrates > Grey squirrel

Determining the effects of grey squirrel damage on timber

Aim of study

Bark-stripping damage on young oak tree

This study aims to evaluate the impact of bark-stripping damage on the main stem to young oak trees, to provide information on:

  • Size of tree at risk
  • Effect of damage on tree growth.

Results to date

Measurements of tree height, size, and dominance have been recorded since 1998 for a stand of naturally regenerated oak along with annual records of bark stripping damage on the main stem.

Analysis of the first 5 years data shows that trees most at risk of damage in this stand are dominant trees with a diameter at breast height of 7.5cm or more. Damage occurred most usually above 4m on the main stem and led to dieback, loss of apical dominance and a reduction in top height increment. Continuing damage is likely to lead to a reduction in yield for the stand.

Grey Squirrel bark stripping damage - a case study (PDF-4250K)
Presentation slides