Figure 1.

Schematics of the expected trend in composition and structure of the secondary wall and associated maturation stress from compression wood to tension wood. CW, compression wood; OW, opposite wood; NW, normal wood; MTW, mild tension wood; STW, severe tension wood. For lignin content, branching arrows illustrate the difference between lignified G-layer in the continuation of the slope and unlignified G-layer where lignin content of wood decreases steeply when the G-layers become thicker and S layers thinner. (Online version in colour.)