Words of caution 4.1

The questions raised about invasive species and ecosystem disservices are real and should not be dismissed and it is true that the introduction of a new species does significantly increase the chance of the introduction of an invasive species particularly with a changing climate and other localised conditions prevalent in a particular environment.

Other research differentiates between introduced and invasive species and argues that not all introduced species are invasive and that the two terms should not be confused. Introduced species are those species which have been introduced to northern Europe since the last ice age with invasive species, a sub- group, which spread and maintain populations without human intervention.

Sjoman (2012)

While the above views urge caution and introduce sensible discussion points the fundamental proposition that diversity in a tree population will increase resilience is not challenged.