Annual growth rings in the mangrove Laguncularia racemosa (Combretaceae)

Abstract

Stem discs from trees of known age were used to determine the periodic nature of the growth rings formed in Laguncularia racemosa and to describe the anatomical features of these rings. The growth rings were scarcely distinct on microscopic examination, but they were well distinguishable macroscopically, with alternating light brown and dark brown layers. Cross-dating analysis revealed the occurrence of annual growth rings in L. racemosa. The existence of annual growth rings in L. racemosa suggests that it may have great potential for dendrochronology and should encourage age-related studies on the dynamics of mangrove forests. These studies can be important for the evaluation of climate change impact on mangrove ecosystems, as well as for the analysis of effects related to climate variability on plant communities.

Occurrence of annual growth rings in Rhizophora mangle in a region with low climate seasonality

“…According to the Köppen classifi cation, the regional climate can be divided into Aw (tropical hot and wet with a dry season during the winter), which is typical of the lowlands, and Af (tropical hot and wet with no dry season), which is characteristic of the adjacent slopes. According to Estrada et al (2008), the average annual temperature is 23.5 °C, and the average annual precipitation is 1,067 mm, with a weak tendency to wetter summers and drier winters. The same authors describe a high interannual variability in the precipitation pattern, with summer and winter alternating as the wetter period in the last 30 years.…”

“…ESTRADA, MÁRIO L.G. SOARES and CÁTIA H. CALLADO mangrove species: Rhizophora mangle (Menezes et al 2003), R. mucronata (Verheyden et al 2004), R. apiculata (Yu et al 2004), Sonneratia apetala and Heritiera fomes (Chowdhury et al 2008), Laguncularia racemosa (Estrada et al 2008) and Luminitzera racemosa (Robert et al 2011). In most of these studies, the formation of annual rings is related to some degree of climate seasonality.…”

“…In most of these studies, the formation of annual rings is related to some degree of climate seasonality. However, in low seasonality conditions, the distinctness of the growth rings may be lower, making it more difficult to identify their limits (Estrada et al 2008), preventing them from being used in dendrochronological studies (Robert et al 2011). …”

A Review of Sea-Level Rise Effect on Mangrove Forest Species: Anatomical and Morphological Modifications

“…Laguncularia racemosa from Rio de Janeiro, Brazil, also present distinguishable growth rings macroscopically, with alternating early wood formed between spring and autumn and consists of layers with abundant paratracheal axial parenchyma, while late wood is formed in winter and consists of narrower dark layers which are basically fibrous zones with scarce paratracheal axial parenchyma. The occurrence of a dry season in winter could be the seasonal factor determining the formation of annual rings (Duque Estrada et al, 2008). These results are relevant because a factor that may be important for the future of mangrove ecosystems is any change in precipitation (Field, 1995).…”

Issues and Challenges of Mangrove conservation in the Anthropocene

“…In Rhizophora forests growing on saline and brackish soils in the state of Para in Brazil, Menezes et al (2003) showed that trees developed annual rings (checked with the 14 C technique) but the anatomical features were better defined in saline than in brackish sites. Anatomical analyses showed also the occurrence of annual rings in L. racemosa growing in the State of Rio de Janeiro, Brazil (Estrada et al, 2008).…”