Ask Mr. Smarty Plants

Since we are neither entomologists nor plant pathologists, we would like to refer you to this article from the Florida Department of Agriculturee, Forestry Division Common Causes of Oak Mortality. When we in Central Texas hear of the decline of a Live Oak, we immediately think that there might be the presence of Oak Wilt, which has been decimating Live Oaks here. However, this article says that, as of yet, no Oak Wilt has been detected in Florida. On the other hand, this article from the University of Florida Extension Service is titled: Oak Wilt-A Potential Future Threat to Oak in Florida.

We are not too sure your landscapers are the right ones to ask about your trees; in fact, tree problems are sometimes caused by incautious spraying of herbicides or pesticides by landscapers onto grass surrounding the trees. "Weed and feed" fertilizer, which kills broad-leaf weeds in the lawn can also damage the trees, which are themselves broad-leaf plants. We would suggest you either contact a certified professional arborist and ask for an opinion, or contact the University of Florida Extension Office for Duval County. If the trees in your neighborhood are all still looking good, then there is probably a localized reason for yours looking bad.