Will it hurt to spray Manor close to loblolly pine trees that are 3 to 4...
Manor is a turfgrass maintenance herbicide and is not labeled for use around pine stands. You would be breaking the label directions using it in such a locale. (http://www.cdms.net/ldat/ld6KL006.pdf)
For treatment with Metsulfuron (the active ingredient in Manor) you should look to a formulation like Escort (http://www.cdms.net/ldat/ldCFM000.pdf).
If you are working with a landscape instead of a pine stand, be aware that Metsulfuron has been problematic around trees of many species, particularly oaks. See the attached paper (https://edis.ifas.ufl.edu/pdffiles/FR/FR40000.pdf).
Hope this is the information you were looking for. Always use pesticides according to their label directions!