Turno biológico de corta para Cedrela montana Moritz ex Turcz., y Cedrela odorata L. en la reserva biológica San Francisco (Zamora Chinchipe) y en un bosque natural del sector El Tambo (provincia de Loja)

To know the growth dynamics of trees is very important for forest management, especially in species with high commercial value. Biological Rotation Age (BRA) is indispensable to ensure the sustainability of a forest ecosystem and is the basis to regulate a Minimum Cutting Diameter (MCD) on technical and scientific grounds. However, this requires annual records and permanent plots of an entire tree growth period. In our environment it is difficult to find this information and permanent plots are very scarce. Therefore, this study used dendrochronological methods to get this information with great precision from tree-rings. The goal of this research was to know the BRA of Cedros trees, and it was carried out in two scenarios: the first was in the site El Tambo of Catamayo canton, province of Loja with the tree species Cedrela montana Moritz ex Turcz, and the second scenario was in the Biological Reserve San Francisco (RBSF) belonging to the site Sabanilla of Zamora canton of Zamora Chinchipe province with the species Cedrela odorata L. To do this, 2 to 4 increment cores were taken in a radial direction with the help of a Pressler borer. A total of 35 trees were sampled: 23 from the RBSF and 12 from El Tambo, which were prepared and sanded from the largest to the smallest grain size in order to guarantee the good visibility of tree-rings, to facilitate the identification, and to measure the tree-rings with the use of the LINTAB6 Pro system and the TsapWin software in the Dendrochronology laboratory of the Universidad Nacional de Loja. Data management and analysis was performed on the statistical platform R with the base functions and the specialized dendrochronology package "dplR". To determine the sample size was used the Expressed Population Signal (EPS) statistic which resulted in a high value of 0.907 for El Tambo with 12 trees, and for the RBSF an EPS = 0.749 with 23 trees. Through the tree-ring count an average age of 57 years was determined for Cedrela montana in the RBSF and 46 years for Cedrela odorata of the El Tambo site. In the analysis between the Mean Annual Increase (MAI) and the Current Annual Increase xxi CAI) for Cedrela montana of the RBSF it was demonstrated that the Cedro still do not reach their BRA, but with a linear projection of the MAI and polynomial of grade 2 of the CAI an approximate BRA of 95 years was calculated where the trees would reach a DAP of 50 cm. Meanwhile, in El Tambo the Cedros trees directly reached their BRA at age 59 with a DBH of 48.28 cm. With the results obtained based on the BRA, it was found that the values differ from the one proposed in the Ecuadorian forestry normative where all Cedros species are attributed a MCD of 60 cm, which is not sustainable for the use of these species in native forest, because according to the data obtained in this study the Cedros take more than 95 years to reach a diameter of 60 cm especially in Cedrela montana which has a slower growth than Cedrela odorata. Keywords: Cedrela, biological rotation age, MAI, CAI, dendrochronology, Minimum Cutting Diameter, montane forest.

• Hovedforfatter: Patiño Rosario, Silvana del Carmen (author)
• Format: bachelorThesis
• Sprog: spa
• Udgivet: 2019
• Fag: CEDRELA; CEDRELA ODORATA
• Online adgang: http://dspace.unl.edu.ec/jspui/handle/123456789/22564