Climate response of cell characteristics in tree rings of Picea crassifolia

Dimensions of dated tree rings are an important tool of dendroclimatology. However, the relationships between climatic variables and cell diameter and cell wall thickness are not yet clearly elaborated. In the present article, year-to-year cell characteristics, ring width, and wood density of Picea crassifolia trees growing in north- western China have been measured with high resolution by means of the instrument SilviScan-3. The response function analysis showed that climate explained 51% of the variation of cell radial diameter chronology, 48% of wood density, 40% of cell wall thickness, and 37% of ring width. Cell wall thickness and wood density responded significantly and positively to temperature, and the response to precipitation was negative, while the opposite was true for cell radial diameter and ring width. Cell wall thickness and wood density were pronounced (statisti- cally significant) to temperature in September and precip- itation in May and August. Cell radial diameter responded significantly to temperature in June and July, and precipi- tation, in August. For ring width, the temperature in July was important. Accordingly, cell characteristics are sen- sitive to climate, and the findings could be useful in the field of dendroclimatology.