Hello, this is my first time trying to make maple syrup and need a little help. I have only a few drops of sap after having them tapped for about a week. The temp has been below freezing at night and above during the day.the taps are on the southwest side of the tree. I am in central massachusetts and beginning to wonder if I either missed the season or am getting my trees confused and not tapping silver maples like I think I am. Any suggestions?