Critical temperature and precipitation thresholds for the onset of xylogenesis of Juniperus przewalskii in a semi-arid area of the northeastern Tibetan Plateau - Ren, Ping (Chinese Academy of Sciences. Institute of Tibetan Plateau Research) ; Rossi, Sergio (Rossi Heras) (Université du Québec à Chicoutimi. Département des Sciences Fondamentales) ; Camarero, Jesús Julio (Instituto Pirenaico de Ecología) ; Ellison, Aaron M. (Harvard University) ; Liang, Eryuan (Chinese Academy of Sciences. Institute of Tibetan Plateau Research) ; Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)