What kind of tree is this?
From the photo this very small seedling appears to be a red maple sp. (Acer rubrum). The leaves are palmate shaped and 3-lobed with acute sinuses and serrate margins (although, but the petiole is not red). The upper leaf surface is light green, but your photo does not show the underside of the leaf, which should be much paler and somewhat glaucous. A red maple will have leaf arrangements on their branches that are opposite each other. From this photo, that characteristic is not distinguishable. You may have to let it grow-out for a few years to see what type of fruit it produces. Red maple trees are found from sea level to 6,000 feet and in a broad ecological range from dry upland slopes to floodplains to swamps. They are native to almost the entire State of Florida. ~DOT