Lauraceae: A promising family for the advance of neotropical dendrochronology

The botanical family Lauraceae is ecologically and physiognomically very important in neotropical forests. It is one of the most frequent and distributed family both in number of individuals and species. Despite of this, we have noticed that a very few Lauraceae species have been considered in dendrochronological investigations. In order to analyze the potential of Lauraceae species in dendrochronology and to facilitate future studies we: (1) reviewed the literature on wood anatomy, cambial activity, tree growth and dendrochronology and compiled a list of species' tree-ring features throughout the Neotropics; (2) Investigated wood anatomy, growth synchronism and climate-growth relationship using dendrochronological standard techniques in 14 species from subtropical forests of southern Brazil. Our review pointed out that the majority of Lauraceae forms distinct tree-rings in several biomes and climates in the Neotropics. Seasonal growth pattern related to water stress and to seasonal air temperature were identified in Amazonia and in subtropical high elevation sites, respectively. Time series of tree-ring width of Lauraceae species were successfully cross-dated and were already used in reconstruction of fire and vegetation dynamics. Our own dendrochronological investigations brought to light that all the 14 studied species form distinct tree-rings in seasonal or even rainforests. By analyzing time series of tree-ring width we found the same growth tendency within trees of Cinnamomum amoenum and Ocotea pulchella. Moreover, year-to-year variation in the growth time-series was linked to climate variations of temperature and precipitation, showing growth decreases when summer water stress occur. We evinced Lauraceae has distinct, synchronic and climate-sensitive tree-rings. Therefore, since Lauraceae has wide distribution and high frequency in the Neotropics and since many species become centenary, we strongly encourage the use of Lauraceae's tree-rings in autoecology, climatology and on the reconstruction of vegetation and disturbance dynamics.