Actividad vegetativa, tasas de crecimiento y estimación de la edad de los individuos en los rodales de polylepis reticulata del Parque Nacional Cajas

Abstract

This research is related to the physiology and phenology of stands of Polylepis reticulata and its response to fluctuations in temperature. The growth of the trees is determined in the current study. At first we tried to determine the growth of the P. reticulataby analyzing the growth rings (dendrochronological method), in which no positive results were obtained due to the lack of seasonality in the climate at the study area. Therefore we chose to install dendrometers (artisanal and electronic) which allowed the continuous record of tree growth. 64 artisanal and 5 electronic dendrometers weremounted onP. reticulata trees, located on three hill sides (Taquiurco, Toreadora and San Luis) in the Cajas National Park. With the data recorded by the electronic dendrometers, we intended to determinate the phenological response of the trees through the application of a vegetative activity model using temperature as a main estimator we aimed to determine the influence of low temperatures on the vegetative activity of the tree. Analysis of the data resulted the definition of a minimum threshold of 6 ° C below which the vegetative activity decreases significantly showing that the temperature is the key factor that regulates the growth of P. reticulata. Furthermore we reconstructed thegrowth patterns of Polylepisreticulataand determined the annual increase of the cross section of trees in the different diameter classes presented in the study area. Once determined the growth rate, the age of the individuals in Cajas National Park was estimated.