|Dressed for the winter.|
Our weather is changeable, even in mid-winter. At times, after a week or so of warm, sunny days, the temperature will drop suddenly, overnight, and howling winds will drive the chill even lower. At these times, sap that has been rising in the warmed trees suddenly freezes, splitting the bark, killing saplings.
In our gardens and yards, we rush out (if we have been procrastinating, as usual) and wrap our young trees in burlap or plastic or whatever we have on hand to cut the wind. One year, I used leftover carpet cuttings. Whatever works.
In the wild, the trees are on their own. A thick lichen outfit is a lifesaver.