Selecting the tree species that favour red squirrels but are unlikely to encourage grey squirrels into the core area is of paramount importance. Favourable species include Scots pine, larch, Norway spruce, lodgepole pine, Douglas fir, yew and hawthorn. Even a commercial plantation consisting primarily of the North American conifer Sitka spruce, can contribute to red squirrel conservation, providing that 20% of the tree cover consists of the above favoured species , where suitable site conditions prevail.

Woodland managers who require broadleaves for landscape or biodiversity reasons should use any of the following species - birch, rowan, ash, willow, aspen or alder. These species produce small seed and although they are not a favoured food source for the red squirrel, they do not encourage grey squirrel incursions.