Authors: Sisimac Duchicela*, University of Texas - Austin, Katya Romoleroux, Pontifical Catholic University of Ecuador
Topics: Biogeography, Mountain Environments, Environmental Science
Keywords: radial tree growth, decomposition, leaf turnover, dendrometer
Session Type: Paper
Start / End Time: 1:20 PM / 3:00 PM
Room: Regent, Marriott, River Tower Elevators, 4th Floor
Presentation File: No File Uploaded
The species of the genus Polylepis are endemic to the Andes and occur at an altitudinal range of 3,000 to 5,000 meters above sea level. It was proposed that these forests covered large extensions of land and then were reduced by human activity. The physiological adaptations of the Polylepis species have produced a specialization in their forest dynamics. The main objective of this study is to demonstrate aspects of its dynamics, including tree radial growth, leaf turnover and decomposition. Three species of Polylepis in two forests of the Ecuadorian Andes, Inga and Chimborazo were studied. To quantify the radial growth, manual and digital dendrometers were used in 21 trees of each species. Branch longitude and leaf turnover was determined from those trees. Additionally, precipitation, volumetric percentage of water in the soil and temperature was measured during the year and a half of fieldwork. Field and laboratory decomposition were calculated using dead leaves as biomass. Results showed that Polylepis reticulata grows at a much slower rate than those species found in the Inga forest and that it is related to water availability. For this species, leaf turnover is less frequent and decomposition rates were slow, which means that the Chimborazo soil has a low nutritional quality. Polylepis incana and Polylepis pauta had frequent leaf turnover exposing high nutritional quality. Therefore, tree growth is still occurring in areas considered less suitable. However, water availability plays an important role in the development and growth of these trees.