Climatic signal in cellulose microfibril angle and tracheid radial diameter of Picea crassifolia at different altitudes of the Tibetan plateau, northwest China

Little attention was given to the climatic signals in wood properties, such as microfibril angle (MFA) and tracheid radial diameter (TRD). In this article, year-to-year variation in MFA and TRD was measured by SilviScan-3 on dated Piceacrassifolia trees growing at three altitudes in the northeastern Tibetan plateau. Climatic signals registered in MFA and TRD were analyzed using dendroclimatology methods. The annual variation of MFA and TRD was strongly linked to high-frequency climatic signals. Both MFA and TRD were negatively correlated with temperature and positively correlated with precipitation. The temperature had a similar influence on MFA and TRD at three different altitudes, while the influence of precipitation decreased with the increasing altitudes. MFA was negatively correlated with TRD, and this MFA–TRD internal relationship (R_t) varied with calendar year. Temperature and precipitation had a strong influence on R_t. Temperature was positively correlated with R_t, and precipitation was negatively correlated with R_t. The influence of temperature was stronger than that of precipitation. The influence of temperature increased with the increase in altitudes, while the influence of precipitation decreased with the increasing altitudes. Results of this study revealed that the trees could change their internal characteristics to adapt to the changing climate.