A palm needs plenty of thick roots generated from the stem. As these roots frequently develop close to the surface the roots of a Trachycarpus fortunei can become damaged from temperatures around minus 8 degrees Celsius. So damage occurs here much more readily than at the crown. A common mistake is that a palm is quickly unpacked while the roots are still half frozen. This causes dehydration because the root system can't absorb water. Palms in pots are even more vulnerable and should be protected from -8C by pot protectors. To avoid root damage by frost, it is advisable to apply a mulch layer first and then to to cover it with the special root protector.