Historic Marker number 104 is located at 804 Caroline Street between Margaret and William Streets. It can be said that the building foundation of Key West was built on Dade County Pine. Dade County pine is a highly prized old growth lumber that was the primary source of wood used to build most of the buildings in Key West’s Historic District. It is best known for its ability to withstand rotting conditions and stand up to termite damage. It was used for every aspect of a structures’ construction. Inspect any old house in the Historic District and you will find Dade County Pine was used to construct floors, walls, ceilings, framing, windows, doors, trim, stairs, and support beams. The “Dade County” name is somewhat of a misleading term for all of the pine used to build the city. Much of the lumber used in the construction of Key West was harvested outside of Dade County, Florida. Somehow, the name became synonymous with all Longleaf Southern Yellow Pine. Dade County Pine, a subspecies of Longleaf Southern Yellow Pine, comes from the “heart” of the tree and is a favored construction material wood because it is strong, dense, and highly resistant to decay and insect damage. The strength of this old growth lumber comes from a weather phenomenon found along land abutting large bodies of salt water. Salt laden spray and mist travels inland on a daily basis. The salt particles coat vegetation and tend to retard growth. Trees growing along shorelines up to 5 miles inland from salt water tend to grow at a slower rate. The long-term result of this slower growth in trees is the formation of tighter growth rings with less sapwood in between. Sapwood is the softer living parts of the tree were sap flows. Tighter growth rings give the wood its strength and less sapwood greatly reduces the food that insects thrive on. In the 1800s, Dade County Pine was harvested from the Florida Everglades, the western shores of Florida, and as far north as the Gulf shores of Georgia and Alabama. Wood mills were built on lumber harvesting sites and fleets of sailing ships laden with fresh-cut logs headed to Florida Territorial cities like Key West. Sadly, old growth Dade County Pine was over overharvested and is no longer available except from salvage operations. Modern construction material’s wood equivalent is grown in tree farms and is far inferior to the slow growth lumber from the past. Today the emphasis is on growing trees quickly for more frequent harvests leaving the end product with less growth rings and an excess of soft sapwood.