The Influence of S2 Microfibril Angle on Longitudinal and Tangential Shrinkage in China-fir (Cunninghamia lanceolata) Plantation

The first objective of this study was to investigate the variation of microfibril angle (Mfa), tracheid morphology and shrinkage within China-fir (Cunninghamia lanceolata) plantation tree. The second objective was to discuss the relationship between Mfa and tracheid morphology, and the influence of Mfa on longitudinal and tangential shrinkage. The results showed that the mean value of Mfa decreased from the 2nd (30.8°) to 26th growth ring (7.7°); the radial variation of latewood tracheid length ranged from 2653μm (2nd growth ring) to 3851μm (14th growth ring) with rapid increase trend, however, the mean tracheid length increased slowly from 14th growth ring; the latewood tracheid width increased rapidly from 27.32μm (2nd growth ring) to 37.12μm (14th growth ring), and then became slow from 14th growth ring; There were strong relationships between Mfa and tracheid morphology; Meanwhile, the relationships between both longitudinal and tangential shrinkage and Mfa were curvilinear and linear respecti