Correcting Eccentric Growth Rings Using Basal Area Increment: A Case Study for a Desert Shrub in Northwestern China

Abstract

Because of the eccentric radial growth for shrubs, climatic signals recorded by their ring-width series tend to be distorted. We hypothesized that measured Basal Area Increment (BAI) can overcome such a weakness. We used the desert shrub Zygophyllum xanthoxylum, with eccentric radial growth to test this hypothesis. RWI (mRWI) and BAI standard chronologies were established based on the ring-width data. Then, we converted BAI into RWI and created a transformed RWI (tRWI) standard chronology. Both BAI and tRWI showed higher correlation with climate records than mRWI, although their correlation coefficients were not significantly different from each other. Based on the comparison between tRWI and mRWI chronologies, mRWI overestimates the radial growth of Z. xanthoxylum caused by eccentric form. BAI can be applied to increase accuracy in dendrochronological studies for shrubs with eccentric growth.