Is it feasible to smoke meat with spruce needles?
It's feasible, but then you'd better really like the taste of turpentine and have the courage to take a chance on ingesting it. Turpentine comes from the oils of pine and -- you guessed it -- spruce. I wouldn't recommend taking a chance on smoking anything using coniferous materials. If you're in an area with spruce, then you probably have alder as well. There's your viable alternative.

Additional info: If you don't have alder handy or you just dislike alder smoke, then wild hazelnut or wild applewood will work just as well. (I use the applewood.) If you don't live where the trees are, most hardware stores that sell wood stove or pellet stove fuel will have wood chips made from hardwood trees. If you live anywhere near an orchard, take a drive to the country and ask a grower if you can buy or reserve some apple, cherry, or nut tree prunings. And finally, if you live in eastern North America, maple and butternut woods make excellent smoking materials.