|Carlos on Paseo de Montejo last week.. see the tree trunk!|
I've googled this question and I have not found an answer that satisfies me. One web site said that the tree trunks were painted white to keep the tree from suffering damages from the extreme temperatures.In further research I found the following: "According to the University of Missouri Extension, white latex paint can also be used to prevent the bark of a tree from splitting and cracking off. This can happen when the tree is exposed to freezing evening temperatures followed by a daytime thawing. The painted white trunk will help reflect sunlight during the daytime hours and keep the tree warmer at night." This, of course, would not be the reason the trees are painted in the Yucatan.
Another reason I found was to to save the tree from injury from animals and insects. According to the University of Vermont, adding a small amount of rabbit repellent to the paint will keep hungry rabbits from gnawing on the tree bark. This might be right in some climates, but in Merida the only rabbit I've ever seen is a mascot of a popular eatery.
In Puerto Rico the beach palms have their trunks painted white. Here it is because people drive between the trees at night and the white paint helps them not run into the trees... the rum may impact their driving skills you know!