Rainfall drives variation in rates of change in intrinsic water use efficiency of tropical forests.

All long-term relationships between c a and W were linear and highly significant (Table 1 ; P < 0.0001)), indicating relative invariance in the ratio of intercellular ( c i ) to c a (as W = c a (1 − c i / c a )/1.6; see Eq.

also in 132,142 other papers