South Florida is distinct from most of the US. It is noticeably more “tropical” than northern and central Florida. Florida does not actually extend into the tropics (which is about 23.4369 degrees (about 23˚ 26′) North latitude; the southernmost part of the Florida Keys is about one degree north of this. However, the close proximity of warm oceans to most of Florida results in a climate that is comparable to many humid tropical locations.
The scarcity of frost and relatively high rainfall has resulted in many tropical plants and animals being found, in the US, only in southern Florida. For example, there are 12 palms native to Florida, but six of these are only found south of Lake Okeechobee and three are only found in the Keys (they are more common throughout the Caribbean). A similar situation exists with regards to epiphytic plants (those that grow on trees for support). Although a very few epiphytic bromeliads and orchids exist in northern Florida, their diversity increases rapidly as one proceeds south. A maximum diversity is found in the hardwood hammocks in south Florida. These hammocks are relatively dry “islands” a few feet above the saturated conditions found in much of the Everglades and support many hardwood trees). Conditions within these hammocks can be warmer than outside, and thus more protective against cold winds. In south Florida there are many epiphytic orchids and 16 epiphytic bromeliad species. Note that an excellent source of information about wildlife and vegetation of Florida is the University of Florida extension site here. And for plants, almost nothing is better than the Florida Plant Atlas (for the botanically-inclined).
When looking at a tree festooned with epiphytes you should recognize that most of these are bromeliads, not orchids. At least in Florida, most of the epiphyte biomass is associated with bromeliads. Orchids tend to be more inconspicuous and smaller.