Quantitative differences in the (a,c) total wound-induced BVOC blend emitted during seven minutes and (b,d) maximum emission rates after (dark grey) straight cuts to the leaf lamina and (light grey) transversal cuts across the midrib of mature leaves of aspen (Populus tremula). The values (average ± SE, n = 35 for lamina cuts and n = 15 for midrib cuts) refer to the (a,b) open wound surface exposed (in mm2) and (c,d) the wound length (in mm), calculated from the leaf lamina thickness, midrib diameter, and cut length. Note the different scales and units used in the y-axes.