The Crooked Chimney has been involved in birch syrup research since 2009. More specifically, we have measured the sugar content of the sap from three different species of birch trees: paper, or white, birch (Betula papyrifera); black, or sweet, birch (Betula lenta); and yellow birch (Betula alleghaniensis). This study took place in Lee and Durham, New Hampshire. We use a sap refractometer, which measures the sugar content in degrees Brix, once every three days throughout the syruping season. Here are the results from 2009 and 2010. We’re happy to answer any questions about this research.