Estudio dendroclimático de Cedrela nebulosa T.D.Penn. & Daza en el bosque húmedo del cantón Mera, provincia de Pastaza, Ecuador

Tropical dendrochronology is in a developmental stage, the advances made during the last 20 years in dendrochronological and dendroclimatological studies in tropical and subtropical areas in South America are limited to the lowlands and the Amazon basin. These studies allow us to precisely quantify the radial growth rate of different species in various sites and compare them with information from the soil, disturbances, and climate to verify their influence on annual growth. For this reason, this dendroclimatic study of Cedrela nebulosa T.D.Penn. & Daza in Ecuador, has the objective of knowing the influence of precipitation and temperature on the annual diameter growth of Cedrela nebulosa T.D.Penn. & Daza, through dendrochronological methods in the canton of Mera, province of Pastaza in the central Amazon of Ecuador. A total of 33 individuals were sampled (3 discs and 67 cores). The wood samples were prepared in the Laboratory of Dendrochronology of the National University of Loja, and sanded from grain 60 to 4000. Using the Lintab Pro 6 measuring system and TSAP-Win Pro software, each growth ring was identified, measured and synchronized. Climatic data was obtained from INAMHI's meteorological yearbooks, precipitation in the period from 1965 to 2019 and temperature in the period from 1965 to 2017. Data analysis and graphical visualization was performed using the specialized "dplR" package for dendrochronological analysis on the R statistical analysis platform. The results obtained in C. nebulosa showed that these trees have an average age of 46 years, a maximum age of approximately 160 years, and a minimum age of 31 years. Their growth in diameter reached a value of 8,76 mm/year. In general, the growth rate did not vary much in the first years, from 1860 to 1975, and in the end between 1987 and 2010 the growth started to decrease. A calculation of all the trees resulted in a chronology based on growth rings from 1860 to 2019. The radial growth of the C. nebulosa had no influence on the annual precipitation of the site (1965-2019), r= -0,2 (p.value = 0,05). On the other hand, the relationship between growth and temperature (1965-2017) was moderate (r= 0.43). Therefore, it can be concluded that due to the fact that there isn't marked seasonality of drought or rain in the site, rather there is constant and regular rainfall throughout the year, the species did not generate a response of sensitivity to rainfall. On the contrary, the temperature reacted positively and this is a key point to measure the influence of this variable with the growth of the species, that is, as the temperature increases, the width of the growth ring increases. Therefore, it is very important to expand more sites and species for these studies, and to see the possibility of reconstructing the temperature and thus provide the opportunity for new data in remote sites where there aren’t meteorological records. Keywords: dendrochronology, dendroclimatology, growth rings, rainforest, annual growth, Cedrela nebulosa, precipitation, temperature