Growth Rings, Growth Ring Formation and Age Determination in the Mangrove Rhizophora mucronata

Abstract

This study reports, for the first time, the presence of annual growth rings in the mangrove R. mucronata, which offers further potential for dendrochronological and silvicultural applications.

Annual cyclicity in high‐resolution stable carbon and oxygen isotope ratios in the wood of the mangrove tree Rhizophora mucronata

“…Despite early reports of the absence of growth rings in R. mucronata (Panshin 1932;van Vliet 1976), we have recently proven the presence of annual growth rings in this mangrove species in Kenya (Verheyden et al 2004). In short, the annual growth rings in R. mucronata consist of a low vessel-density earlywood layer (which visually appears as a dark ring) and a high vessel-density latewood layer (which appears as a light ring).…”

“…Due to the indistinct nature of the growth rings, the exact position of the bound- aries is uncertain (see error bars in Fig. 4a and discussion in Verheyden et al 2004). An exception on the annual cyclicity in the d 13 C profile occurs in the year 1997, which is characterized by a sharp drop in the d 13 C value in the earlywood (Fig.…”

“…2). The earlywood formation starts in April, while the latewood formation starts in November (Verheyden et al 2004; see also Fig. 2).…”

“…In the high-resolution profiles of the stem discs collected from the basin forest (Tw55880 and Tw55891), the lowest d 13 C value is observed at the annual ring boundary, which corresponds to wood formed during April-May and coincides with the onset of the long rainy season (Verheyden et al 2004; see Fig. 2).…”

“…Notes were taken as to which growth ring each sample belonged to, as well as its position in earlywood or latewood. However, due to the indistinct nature of the boundaries (Verheyden et al 2004), an error on the exact location is unavoidable. In a preliminary stage, every contiguous 20 mm wood sample collected from a growth ring was analysed.…”