Why are some tree trunks painted white?

Insect control - (not crickets, of course)

Some believe that it prevents sunburn and damage to the thin layer just beneath the bark that transports water up to the leaves. Crop trees are pruned to get the branches off the ground to make them easier to harvest, but that exposes the trunk to direct sunlight, which would be filtered if the branches were left alone.

I've painted lots of English Walnuts, but I've not observed a difference between the survival rate of painted trees and ones without paint. What I have seen are oak trees stressed by sun exposure on their trunks, but, of course, no one bothers to run around painting oak tree trunks. My guess is that some person noticed that there is an effect on some trees, and analogized to others and decided that there's a benefit to protecting them from exposure. As I said though, can't prove it by me.

A lot of the time tree trunks are painted white to mark them so they will not be cut when logging or tree removal is being done on private property. It is the easiest way to let the people doing the cutting that you want a particular tree or trees left standing

They innicially were given a coat of lime which is white to keep ants from climbing up and eating away at the leaves. It became so popular that some people just painted them white without asking themselves why. Actually it's a poor solution to prevent ants from climbing, they'll climb up anyway.

Some trees are susceptible to sunburn-- and the white paint is protection from that.

they had no paper at the time, so they decided to draw on trees instead

To see in dark

I thought it was to hinder some molds growth. That was what I was taught.

It is to keep some sort of bugs off of them.

b-cus long ago it would hide them in the winter