Desire Paths

Whitewash is applied to trees, especially fruit trees, to prevent sun scald. Most often only the lower trunk is painted. In Poland painting the whole trunk is also said to help keep the body of the tree cool in late winter and early spring months and hence help prevent fruit trees from blooming too soon, i.e. when warm sunny days could promote rapid tree warming, rising sap and bloom and intermittent frosty nights could damage outer tree rings and destroy the young buds and blossoms.

Both summer sunburn and winter sun scald can cause the tree's bark to crack or die, resulting in additional stress which is compounded by insects and parasites that enter the barkless wood, an invasion that will ultimately shorten the tree's life. Tree paint or whitewash protects against this.

The white paint on the trunks helps reflect sunlight and prevents the tree’s bark from getting too much sun. In the winter, an overabundance of sunlight can cause thawing of critical tissues under the bark. They then can refreeze when temperatures drop, leading to trunk cracks and fissures. These wounds are perfect entry points for pests and diseases.

https://www.bobvila.com/articles/why-paint-trees-white/

Are they painted? It looks like they're wrapped in something to me, I'd also like to know why. My first thought was to protect against cold or weather.

In europe on a pond I’m managing we have select tree bottom parts painted with silica paint which happens to be white to protect as much as possible against beavers and shit. It is apparently not nice on their teeth's.

People say it's keep them safe from bugs. I think the link the other person shared sums it up pretty well.