The BOREAS TE-09 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. This data set describes the relationship between Photosynthetically Active Radiation (PAR) levels and foliage nitrogen in samples from six sites in the BOREAS NSA. This information is useful for modeling the vertical distribution of carbon fixation for these different forest types in the boreal forest. The data were collected to quantify the relationship between PAR and leaf nitrogen of black spruce, jack pine, and aspen.