Is The Amount Of Feeding Damage Related To Population Size Of Voles?

How many voles need to occur in a given plantation to create a serious damage problem? A risk rating for feeding damage to trees, based on an index-line or grid survey of voles, is derived from the significant positive relationship between percentage tree mortality and abundance of Microtus voles.

 

British Columbia Vole Population Data

Vole Population Data 2010 (PDF)