Fig. 7
(a) SEM images showing the channels in the tangential section of poplar opposite wood. The vessel channels are highlighted with yellow dotted lines and the pits on the side wall of the vessel are highlighted with a red circle. Inset is an isolated single vessel. (b) Diagram of vessels in poplar opposite wood (OW) and tension wood (TW) based on wood segregation and SEM measurements. (c) Contours of velocity (m s−1) for air and N2 transport in the vessels of TW and OW based on the Fluent analysis. (d) Air and N2 velocity profiles for TW and OW at different locations (inlet and outlet) based on the Fluent analysis