Economic and Environmental Damage Caused by Grey Squirrels

Economic and Environmental damage caused by grey squirrels

– It is estimated that grey squirrel bark stripping damage costs the UK timber industry some £14 million per annum. Trees planted using grant funding are being destroyed by grey squirrels at an additional cost to the UK taxpayer.

– Tree species which are growing vigorously with rich phloem vessels in the bark are most vulnerable between the ages of 10 and 40 years.

– Beech, sycamore, oak, poplar, sweet chestnut, birch and cricket bat willow are the most susceptible to damage. Within the UK it is difficult to recommend the planting of beech and sycamore without good grey squirrel control.

– Back in 2000, a survey by the Forestry Commission of vulnerable woodlands in Great Britain estimated that 100% of sycamore, 66% of beech, 30% of oak and sweet chestnut stands had been damaged by grey squirrels. We are still suffering damage and need to keep working on landscape-scale control strategies.

– A few tree species including cherry and ash are not damaged by grey squirrels. Unfortunately, ash is threatened by Chalara fraxinea (ash dieback) disease which removes a species not vulnerable to grey squirrel attack.

– In time, susceptible tree species such as beech, poplar, sweet chestnut and oak may be lost from the mature woodland canopy, with a corresponding loss of associated fungi, invertebrates and their predators.

– Grey squirrels eat song-bird chicks and eggs. Research carried out by the Game Conservancy and Wildlife Trust demonstrates that grey squirrels have an adverse impact on many native woodland birds, reducing fledging rates by an average of 15%.

– Grey squirrels can damage maize and fruit crops. They are a threat to orchards and market gardens. They destroy bulbs and corms, eat tree nuts, recently sown seeds and enter into roof voids, damaging thatched and shingled roofs, telephone wires and electricity cables.

– Grey squirrels have driven the native red squirrel to localized extinctions by out-competing the red squirrel for food and habitat and by carrying a lethal squirrel pox virus to which it is immune but which is deadly to the native red squirrel.

Excerpts taken from The Grey Menace by Andy Wiseman, Squirrel Magazine, Spring 2016, European Squirrel Initiative, Click here to read more.