Suitability of chestnut earlywood vessel chronologies for ecological studies

Wood anatomical features measured in dated tree rings have often proven to be of ecological value. However, little is known about the suitability and power of such measurements studied in a year-to-year basis as is done in dendrochronology. The present work is based on a comparative analysis of 60 dated time-series of earlywood features of chestnut (Castanea sativa) grown in the climatic context of the Southern part of the Swiss Alps. It has been shown that the earlywood vessel area is a suitable ecological indicator. This variable, although not very sensitive, contains environmental information that is different from that stored in all other ring-width and earlywood features we considered. The vessel size is mainly related to the temperature during two physiologically crucial periods for vessel growth: the end of the previous vegetation period (during reserve storage) and the onset of cambial activity (during cell division and vessel differentiation). Our work shows that the mean vessel size of the ring-porous chestnut contains ecophysiological information that can be used for research in dendrochronology.