Dendrometers reflect physiological growth, leaf flushing cycles and water stress levels of cocoa trees

Abstract

We aimed to understand the development of cocoa trees in the semi-arid conditions of Brazil. Dendrometers continuously measure stem diameter variations of trees, displaying the trees’ direct reaction to endogenous and exogenous factors. We analysed Daily Shrinkage (DS) and Daily Net Growth (DNG) with specific regard to the plants’ behaviour regarding the flushing of new leaves.We monitored the stem diameter of 15 trees over a period of 6 months. Additionally, we scored the plants leaf flushing behaviour. We found that DNG was determined by flushing behaviour, whereas environmental stressors determined DS. The largest growth of the trunk occurs during the no-flushing stage, whereas hardly any stem growth takes place during the flushing of new leaves. Once the new flushes are mature, the growth of the stem starts again. Daily Shrinkage, on the other hand, is affected by climatic parameters, where the level of shrinkage increases with increasing evapotranspiration.