Quantifying Eucalyptus Transpiration Using the Dissipation Thermal Technique in Porto Seguro, Bahia

Abstract

Granier’s sap flow method proved to be an important tool for estimating transpiration in woody plants. The present work aimed to estimate the transpiration of two clones (VCC0865 and CO1407) of a hybrid of the eucalyptus species Eucalyptus grandis × Eucalyptus urophylla, in order to understand the efficiency and patterns of water use in the forest ecosystem. The experiment was carried out on a eucalyptus farm in the municipality of Porto Seguro, located in the extreme south of Bahia. The spacing between trees was 3.60 m × 2.50 m. Sap flow measurements were performed daily, between February and December 2022, using 10 sensors installed in tree trunks, according to Granier’s thermal dissipation method. Data were recorded in the datalogger model CR10X system. For the systematization and analysis of the data, the R programming language was used. The results obtained indicated that the beginning of the transpiration period of the clones occurred around 07:00. On rainy days, less transpiration was observed in both clones.  There were no significant changes in sap flow between dry and rainy seasons. It was also found for clone VCC0865 a transpiration rate of 43% higher in the daily average compared to clone CO1407. The present work is an important tool to contribute with information about transpiration in eucalyptus cultivation in the extreme south of Bahia, since there are few studies on the subject and given the importance of the activity in the region.