Britain's Prince Charles is urging landowners to eradicate gray squirrels to save trees from being destroyed. “The greys are doing immense and increasing damage to hardwoods all over the country and threaten to compromise all our efforts to restore native woodlands,” he wrote in a letter to Britain's Country Land and Business Association (CLA). Grey squirrels damage broadleaved trees by nibbling the inner bark, making it hard for owners of forests and woodland to grow the hardwoods required for financial viability, the CLA wrote in a study. The prince added that wiping them out would also be the only way of saving Britain's native red squirrels, which are weaker than their grey counterparts. Unlike the grays, red squirrels can die from a virus carried by both species of squirrel, and the squirrel parapoxvirus is believed to have killed up to 80 percent of the red squirrel population in 2008.