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Fig. 2. Dependence of leaf size on foliar nitrogen content and on total tree height in Betula nana, B. pendula and B. pubescens. All data were fitted by a single multiple linear regression: logS = –0·190 + 0·358logH + 0·447NM (r2 = 0·60, P < 0·001 for both logH and NM, P > 0·1 for the intercept). Symbols as in Fig. 1.
