Total N and C analyses
Total foliar N and C content was determined in foliage collected in late August 2016, and early June and late August 2017 (n= 5-6). The tissue was dried for 72 h at 70°C, ground using a mini Wiley Mill (Thomas Scientific, Swedesboro, NJ) and passed through a 0.85 mm sieve (#20 mesh). The samples were dried at 70°C for additional 16 h before aliquots of 3 to 5 mg dry weight were sealed in tin capsules. The material was sent to the Stable Isotope Mass Spectrometry Laboratory at Kansas State University in 2016 and to the Stable Isotope Core Laboratory at Washington State University in 2017 for analysis following the methods of Nippert et al. (2013) and Révész et al.(2012), respectively. Briefly, the samples were run through an elemental analyzer using glutamic acid and acetanilide as standards, respectively, to determine N and C content.