Generally, when the bark comes off trees it is because the trees are getting sunburned. The bark on African sumac and jacaranda is thin and can sunburn easily when exposed to full sun especially during the summer months. Citrus trees that are pruned up exposing the bark to the full sun can easily sunburn and the bark will creak and peel off. Paining the bark of trees that have thin bark that is exposed to the full sun can help. There is a paint made for this purpose or you can use a light colored latex paint that has been thinned with water. Thick full-strength paint can block the pores of the bark. There may be other reasons that the bark is coming off. Recommended Extension Article: Sunscald of Trees