Landowners, timber owners and bird shooters are all up in arms against the greys, quite literally, in the name of protecting the native red squirrel. Some conservationist charities such as The Wildlife Trusts have joined the onslaught, helping to perpetuate the myth that killing grey squirrels helps red squirrels with no evidence that the cull actually works.3

The fact that greys do some damage to trees is often given as an excuse for killing or trapping them, and this is no different to the reason Red Squirrels were killed and trapped in the early 20th century. However, the level of damage that greys do to trees is often exaggerated by conservationists and gamekeepers, as supporting evidence for their killing them. Most commonly it is during the late summer mating season that greys strip bark from trees, which can be to give them a lining for their nests, although sometimes the sweet sap beneath the bark does serve as a good emergency food supply.4

Key points at a glance

1. Both Grey Squirrels and Red Squirrels strip bark from trees.4

2. The bark provides good lining for their nests, and the sap beneath can serve as a good emergency food supply when times are hard.4

3. Stripping bark seldom kills trees, but the damage is often exaggerated as an excuse to kill them.4

4. Forestry practices can be changed and improved to vastly reduce the problems associated with tree barking.4

5. Damage to trees can be beneficial to woodland birds and improve woodland biodiversity.4

Effect of squirrels on trees in commercial woodlands

Similarly like in non-commercial woodlands squirrels can cause statistically incidental damage to trees. It's hard not to notice that the problem of tree damage that may be caused by squirrels has been overly demonised in the UK for the last 100 years. In many scientific and environmental publications one can easily come across information that one of the main reasons used to justify the killing of hundreds of thousands of red squirrels in the UK in 20th century was allegedly high number of trees damaged by them.5,6,7,8,9 (Of course all the red squirrels killings were conducted using taxpayers money which found its way to the pockets of a small group of people performing "the control of the red pests".10

After over 100 years of research (and experience in forest management) it's been proven beyond any doubt that killing squirrels – as the answer to incidental tree damage they can cause – is not only ineffective and uneconomical8,11,12,13,14 compared to the required resources but usually has the opposite effect than intended.8,14,16 

Even the English Forestry Commission admitted in their report that spending public money for killing squirrels – in order to limit tree damage that squirrels could potentially cause – not only has little effect but also usually does not pay off financially. This opinion is also confirmed – directly or indirectly – by many scientific studies.1, 12, 13, 15,16 In addition to that scientists over 20 years ago proved that in commercial forest plantations the greatest damage result usually form incorrectly planned tree thinning. In the forests where the thinning is performed at the appropriate time the risk of damage to trees by wild animals is decreased several times.17

Decades of studies, scientific and environmental experiments proved many times that correct forest management and planting suitable – more resistant to damage – tree species not only minimises the probability of tree damage by wild animals more effectively but is also much more economical. 8, 12,1 3, 14, 16, 17

Text has been kindly reproduced, with a few minor alterations, from:  

https://viva.org.uk/animals/other-animals/squirrels/