Climate–Growth Relationships in Laurus azorica—A Dominant Tree in the Azorean Laurel Forest

Forests on oceanic islands, such as the Azores archipelago, enable interesting dendroclimatic research, given their pronounced climatic gradients over short geographical distances, despite the less pronounced seasonality. The Lauraceae play an essential ecological role in Macaronesian natural forests. An example is Laurus azorica (Seub.) Franco, a relevant species given its high frequency and physiognomic dominance in Azorean laurel forests. This study aims to quantify climate–growth relationships in L. azorica using a dendroecological approach. We sampled four stands at São Miguel and two stands at Terceira islands, for a total of 206 trees. Following standard dendrochronological methods and rigorous sample selection procedures, we obtained relatively low rbar values and high temporal autocorrelation. Using a stepwise Random Forest analysis followed by Generalized Linear Models calculation, we found prominent effects of present and previous year temperature, but a low precipitation signal on growth rings, with some model variation between stands. Our results agreed with previous observations for broad-leaved species with diffuse porous wood, contributing to increase the baseline dendroecological knowledge about Azorean forests. Due to the high levels of within- and between-stand variation, and to refine the climatic signal analysis, complementary approaches should be explored in the future.

FUNDING: D.C.P. is currently supported by a PhD studentship grant (SFRH/BD/136336/2018) from the Foundation for Science and Technology (FCT) of the Ministry of Science, Technology, and Higher Education. This research was also supported by national funds through the FCT under (FCT) UIDB/50027/2020 (CIBIO). J.J. was supported by the Alexander von Humboldt postdoctoral fellowship and the Slovenian Research Agency (“Forest Biology, Ecology and Technology—P4-0107”).

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