Mineral nutrition is one of several physiological attributes that contribute to the improvement of survival, growth and physiology of tree seedlings after outplanting (Margolis and Brand, 1990). Several studies showed that net photosynthesis, dark respiration and survival were closely related to nitrogen levels in needles (Lamhamedi and Bernier, 1994; Tjoelker et al., 1999; Poorter et al., 2009). Needle nitrogen concentration (Nmass) varies with site climatic conditions, including temperature (Friend et al., 1989). However, little is known about the role of Nmass in thermal acclimation of An and Rd. For instance, Tjoelker et al. (2009) showed that both type I and II acclimation of Rd were unrelated to Nmass in Pinus banksiana.