TRANSPIRAÇÃO PELO MÉTODO DE DISSIPAÇÃO TÉRMICA EM EUCALIPTO

Abstract

The Granier sap flow method has proven to be an important tool for estimating transpiration in woody plants. This study aimed to estimate transpiration in two types of clones (VCC0865 and CO1407) of the Eucalyptus grandis × Eucalyptus urophylla hybrid, in order to understand water use efficiency and patterns in the silviculture ecosystem. The experiment was conducted on a eucalyptus farm in the city of Porto Seguro, located in the far south of Bahia, Brazil. The spacing between trees was 3.60 m × 2.50 m. Sap flow measurements were taken daily from February to December 2022, using 10 sensors installed on the tree trunks, following the Granier thermal dissipation method. The variable data were recorded using a CR10X datalogger system. After the data collection phase, a descriptive analysis and regression study were conducted to evaluate the relationships between variables. The results indicated that transpiration in the clones typically began around 7 a.m. On rainy days, lower transpiration rates were observed in both clones. There were no significant changes in sap flow between dry and rainy periods. It was also found that clone VCC0865 had an average daily transpiration rate 43% higher than clone CO1407, with rates of 59.77 L day−1 and 41.76 L day−1 , respectively. The Granier equation proposed by Rojas-Delgado (2010) proved to be effective for estimating transpiration in eucalyptus species. This study serves as an important contribution to understanding transpiration in eucalyptus silviculture in the far south of Bahia, as there is limited research on this topic despite the region’s significance in the industry.