Growth stresses are highly controlled by the amount of G-layer in poplar tension wood

To determine how gelatinous fibres and gelatinous layers contribute to the magnitude of longitudinal growth stress in tension wood, anatomical measurements of gelatinous fibres were carried out on poplar tension wood (Populus 14551). It was found that (a) no gelatinous fibres were observed under a growth strain level of 0.06 to 0.08 %; (b) almost 100 % of the non-conductive tissues contained gelatinous fibres above a growth strain level of 0.15 to 0.19 %; and (c) the area of fibres, the area of fibres with gelatinous layers per unit of tissue area, and the thickness of the gelatinous layers predominantly influenced the magnitude of growth stress.